Coronary Circulation: The circulation of blood through the CORONARY VESSELS of the HEART.Coronary Vessels: The veins and arteries of the HEART.Coronary Angiography: Radiography of the vascular system of the heart muscle after injection of a contrast medium.Coronary Artery Disease: Pathological processes of CORONARY ARTERIES that may derive from a congenital abnormality, atherosclerotic, or non-atherosclerotic cause.Angioplasty, Balloon, Coronary: Dilation of an occluded coronary artery (or arteries) by means of a balloon catheter to restore myocardial blood supply.Coronary Stenosis: Narrowing or constriction of a coronary artery.Coronary Vasospasm: Spasm of the large- or medium-sized coronary arteries.Coronary Disease: An imbalance between myocardial functional requirements and the capacity of the CORONARY VESSELS to supply sufficient blood flow. It is a form of MYOCARDIAL ISCHEMIA (insufficient blood supply to the heart muscle) caused by a decreased capacity of the coronary vessels.Dogs: The domestic dog, Canis familiaris, comprising about 400 breeds, of the carnivore family CANIDAE. They are worldwide in distribution and live in association with people. (Walker's Mammals of the World, 5th ed, p1065)Coronary Artery Bypass: Surgical therapy of ischemic coronary artery disease achieved by grafting a section of saphenous vein, internal mammary artery, or other substitute between the aorta and the obstructed coronary artery distal to the obstructive lesion.Vasodilation: The physiological widening of BLOOD VESSELS by relaxing the underlying VASCULAR SMOOTH MUSCLE.Vascular Resistance: The force that opposes the flow of BLOOD through a vascular bed. It is equal to the difference in BLOOD PRESSURE across the vascular bed divided by the CARDIAC OUTPUT.Hemodynamics: The movement and the forces involved in the movement of the blood through the CARDIOVASCULAR SYSTEM.Vasodilator Agents: Drugs used to cause dilation of the blood vessels.Blood Flow Velocity: A value equal to the total volume flow divided by the cross-sectional area of the vascular bed.Heart: The hollow, muscular organ that maintains the circulation of the blood.Collateral Circulation: Maintenance of blood flow to an organ despite obstruction of a principal vessel. Blood flow is maintained through small vessels.Acetylcholine: A neurotransmitter found at neuromuscular junctions, autonomic ganglia, parasympathetic effector junctions, a subset of sympathetic effector junctions, and at many sites in the central nervous system.Nitric Oxide: A free radical gas produced endogenously by a variety of mammalian cells, synthesized from ARGININE by NITRIC OXIDE SYNTHASE. Nitric oxide is one of the ENDOTHELIUM-DEPENDENT RELAXING FACTORS released by the vascular endothelium and mediates VASODILATION. It also inhibits platelet aggregation, induces disaggregation of aggregated platelets, and inhibits platelet adhesion to the vascular endothelium. Nitric oxide activates cytosolic GUANYLATE CYCLASE and thus elevates intracellular levels of CYCLIC GMP.Angina Pectoris, Variant: A clinical syndrome characterized by the development of CHEST PAIN at rest with concomitant transient ST segment elevation in the ELECTROCARDIOGRAM, but with preserved exercise capacity.Adenosine: A nucleoside that is composed of ADENINE and D-RIBOSE. Adenosine or adenosine derivatives play many important biological roles in addition to being components of DNA and RNA. Adenosine itself is a neurotransmitter.Myocardial Infarction: NECROSIS of the MYOCARDIUM caused by an obstruction of the blood supply to the heart (CORONARY CIRCULATION).Vasomotor System: The neural systems which act on VASCULAR SMOOTH MUSCLE to control blood vessel diameter. The major neural control is through the sympathetic nervous system.Myocardium: The muscle tissue of the HEART. It is composed of striated, involuntary muscle cells (MYOCYTES, CARDIAC) connected to form the contractile pump to generate blood flow.Blood Pressure: PRESSURE of the BLOOD on the ARTERIES and other BLOOD VESSELS.Blood Circulation: The movement of the BLOOD as it is pumped through the CARDIOVASCULAR SYSTEM.Myocardial Ischemia: A disorder of cardiac function caused by insufficient blood flow to the muscle tissue of the heart. The decreased blood flow may be due to narrowing of the coronary arteries (CORONARY ARTERY DISEASE), to obstruction by a thrombus (CORONARY THROMBOSIS), or less commonly, to diffuse narrowing of arterioles and other small vessels within the heart. Severe interruption of the blood supply to the myocardial tissue may result in necrosis of cardiac muscle (MYOCARDIAL INFARCTION).Coronary Aneurysm: Abnormal balloon- or sac-like dilatation in the wall of CORONARY VESSELS. Most coronary aneurysms are due to CORONARY ATHEROSCLEROSIS, and the rest are due to inflammatory diseases, such as KAWASAKI DISEASE.Regional Blood Flow: The flow of BLOOD through or around an organ or region of the body.Papaverine: An alkaloid found in opium but not closely related to the other opium alkaloids in its structure or pharmacological actions. It is a direct-acting smooth muscle relaxant used in the treatment of impotence and as a vasodilator, especially for cerebral vasodilation. The mechanism of its pharmacological actions is not clear, but it apparently can inhibit phosphodiesterases and it may have direct actions on calcium channels.Endothelium, Vascular: Single pavement layer of cells which line the luminal surface of the entire vascular system and regulate the transport of macromolecules and blood components.Nitroglycerin: A volatile vasodilator which relieves ANGINA PECTORIS by stimulating GUANYLATE CYCLASE and lowering cytosolic calcium. It is also sometimes used for TOCOLYSIS and explosives.omega-N-Methylarginine: A competitive inhibitor of nitric oxide synthetase.Hyperemia: The presence of an increased amount of blood in a body part or an organ leading to congestion or engorgement of blood vessels. Hyperemia can be due to increase of blood flow into the area (active or arterial), or due to obstruction of outflow of blood from the area (passive or venous).Vasoconstriction: The physiological narrowing of BLOOD VESSELS by contraction of the VASCULAR SMOOTH MUSCLE.Coronary Thrombosis: Coagulation of blood in any of the CORONARY VESSELS. The presence of a blood clot (THROMBUS) often leads to MYOCARDIAL INFARCTION.Cardiac Catheterization: Procedures in which placement of CARDIAC CATHETERS is performed for therapeutic or diagnostic procedures.Microcirculation: The circulation of the BLOOD through the MICROVASCULAR NETWORK.Models, Cardiovascular: Theoretical representations that simulate the behavior or activity of the cardiovascular system, processes, or phenomena; includes the use of mathematical equations, computers and other electronic equipment.Coronary Restenosis: Recurrent narrowing or constriction of a coronary artery following surgical procedures performed to alleviate a prior obstruction.Swine: Any of various animals that constitute the family Suidae and comprise stout-bodied, short-legged omnivorous mammals with thick skin, usually covered with coarse bristles, a rather long mobile snout, and small tail. Included are the genera Babyrousa, Phacochoerus (wart hogs), and Sus, the latter containing the domestic pig (see SUS SCROFA).Time Factors: Elements of limited time intervals, contributing to particular results or situations.Perfusion: Treatment process involving the injection of fluid into an organ or tissue.Arteriovenous Anastomosis: A vessel that directly interconnects an artery and a vein, and that acts as a shunt to bypass the capillary bed. Not to be confused with surgical anastomosis, nor with arteriovenous fistula.Coronary Occlusion: Complete blockage of blood flow through one of the CORONARY ARTERIES, usually from CORONARY ATHEROSCLEROSIS.Stents: Devices that provide support for tubular structures that are being anastomosed or for body cavities during skin grafting.Risk Factors: An aspect of personal behavior or lifestyle, environmental exposure, or inborn or inherited characteristic, which, on the basis of epidemiologic evidence, is known to be associated with a health-related condition considered important to prevent.Nitroprusside: A powerful vasodilator used in emergencies to lower blood pressure or to improve cardiac function. It is also an indicator for free sulfhydryl groups in proteins.Heart Rate: The number of times the HEART VENTRICLES contract per unit of time, usually per minute.Treatment Outcome: Evaluation undertaken to assess the results or consequences of management and procedures used in combating disease in order to determine the efficacy, effectiveness, safety, and practicability of these interventions in individual cases or series.Oxygen Consumption: The rate at which oxygen is used by a tissue; microliters of oxygen STPD used per milligram of tissue per hour; the rate at which oxygen enters the blood from alveolar gas, equal in the steady state to the consumption of oxygen by tissue metabolism throughout the body. (Stedman, 25th ed, p346)Electrocardiography: Recording of the moment-to-moment electromotive forces of the HEART as projected onto various sites on the body's surface, delineated as a scalar function of time. The recording is monitored by a tracing on slow moving chart paper or by observing it on a cardioscope, which is a CATHODE RAY TUBE DISPLAY.Extracorporeal Circulation: Diversion of blood flow through a circuit located outside the body but continuous with the bodily circulation.Percutaneous Coronary Intervention: A family of percutaneous techniques that are used to manage CORONARY OCCLUSION, including standard balloon angioplasty (PERCUTANEOUS TRANSLUMINAL CORONARY ANGIOPLASTY), the placement of intracoronary STENTS, and atheroablative technologies (e.g., ATHERECTOMY; ENDARTERECTOMY; THROMBECTOMY; PERCUTANEOUS TRANSLUMINAL LASER ANGIOPLASTY). PTCA was the dominant form of PCI, before the widespread use of stenting.Nitroarginine: An inhibitor of nitric oxide synthetase which has been shown to prevent glutamate toxicity. Nitroarginine has been experimentally tested for its ability to prevent ammonia toxicity and ammonia-induced alterations in brain energy and ammonia metabolites. (Neurochem Res 1995:200(4):451-6)Myocardial Contraction: Contractile activity of the MYOCARDIUM.Bradykinin: A nonapeptide messenger that is enzymatically produced from KALLIDIN in the blood where it is a potent but short-lived agent of arteriolar dilation and increased capillary permeability. Bradykinin is also released from MAST CELLS during asthma attacks, from gut walls as a gastrointestinal vasodilator, from damaged tissues as a pain signal, and may be a neurotransmitter.Propranolol: A widely used non-cardioselective beta-adrenergic antagonist. Propranolol has been used for MYOCARDIAL INFARCTION; ARRHYTHMIA; ANGINA PECTORIS; HYPERTENSION; HYPERTHYROIDISM; MIGRAINE; PHEOCHROMOCYTOMA; and ANXIETY but adverse effects instigate replacement by newer drugs.Nitric Oxide Synthase: An NADPH-dependent enzyme that catalyzes the conversion of L-ARGININE and OXYGEN to produce CITRULLINE and NITRIC OXIDE.Dose-Response Relationship, Drug: The relationship between the dose of an administered drug and the response of the organism to the drug.Compliance: Distensibility measure of a chamber such as the lungs (LUNG COMPLIANCE) or bladder. Compliance is expressed as a change in volume per unit change in pressure.Coronary Care Units: The hospital unit in which patients with acute cardiac disorders receive intensive care.Myocardial Reperfusion: Generally, restoration of blood supply to heart tissue which is ischemic due to decrease in normal blood supply. The decrease may result from any source including atherosclerotic obstruction, narrowing of the artery, or surgical clamping. Reperfusion can be induced to treat ischemia. Methods include chemical dissolution of an occluding thrombus, administration of vasodilator drugs, angioplasty, catheterization, and artery bypass graft surgery. However, it is thought that reperfusion can itself further damage the ischemic tissue, causing MYOCARDIAL REPERFUSION INJURY.Pulmonary Circulation: The circulation of the BLOOD through the LUNGS.Angina Pectoris: The symptom of paroxysmal pain consequent to MYOCARDIAL ISCHEMIA usually of distinctive character, location and radiation. It is thought to be provoked by a transient stressful situation during which the oxygen requirements of the MYOCARDIUM exceed that supplied by the CORONARY CIRCULATION.Infusions, Intra-Arterial: Regional infusion of drugs via an arterial catheter. Often a pump is used to impel the drug through the catheter. Used in therapy of cancer, upper gastrointestinal hemorrhage, infection, and peripheral vascular disease.Coronary Vessel Anomalies: Malformations of CORONARY VESSELS, either arteries or veins. Included are anomalous origins of coronary arteries; ARTERIOVENOUS FISTULA; CORONARY ANEURYSM; MYOCARDIAL BRIDGING; and others.Analysis of Variance: A statistical technique that isolates and assesses the contributions of categorical independent variables to variation in the mean of a continuous dependent variable.Pulmonary Atresia: A congenital heart defect characterized by the narrowing or complete absence of the opening between the RIGHT VENTRICLE and the PULMONARY ARTERY. Lacking a normal PULMONARY VALVE, unoxygenated blood in the right ventricle can not be effectively pumped into the lung for oxygenation. Clinical features include rapid breathing, CYANOSIS, right ventricle atrophy, and abnormal heart sounds (HEART MURMURS).Biological Markers: Measurable and quantifiable biological parameters (e.g., specific enzyme concentration, specific hormone concentration, specific gene phenotype distribution in a population, presence of biological substances) which serve as indices for health- and physiology-related assessments, such as disease risk, psychiatric disorders, environmental exposure and its effects, disease diagnosis, metabolic processes, substance abuse, pregnancy, cell line development, epidemiologic studies, etc.Glyburide: An antidiabetic sulfonylurea derivative with actions similar to those of chlorpropamide.Ventricular Function, Left: The hemodynamic and electrophysiological action of the left HEART VENTRICLE. Its measurement is an important aspect of the clinical evaluation of patients with heart disease to determine the effects of the disease on cardiac performance.Arteries: The vessels carrying blood away from the heart.Oxygen: An element with atomic symbol O, atomic number 8, and atomic weight [15.99903; 15.99977]. It is the most abundant element on earth and essential for respiration.Prospective Studies: Observation of a population for a sufficient number of persons over a sufficient number of years to generate incidence or mortality rates subsequent to the selection of the study group.Myocardial Reperfusion Injury: Damage to the MYOCARDIUM resulting from MYOCARDIAL REPERFUSION (restoration of blood flow to ischemic areas of the HEART.) Reperfusion takes place when there is spontaneous thrombolysis, THROMBOLYTIC THERAPY, collateral flow from other coronary vascular beds, or reversal of vasospasm.Vasoconstrictor Agents: Drugs used to cause constriction of the blood vessels.Follow-Up Studies: Studies in which individuals or populations are followed to assess the outcome of exposures, procedures, or effects of a characteristic, e.g., occurrence of disease.Ventricular Function: The hemodynamic and electrophysiological action of the HEART VENTRICLES.Aorta: The main trunk of the systemic arteries.Echocardiography: Ultrasonic recording of the size, motion, and composition of the heart and surrounding tissues. The standard approach is transthoracic.Diastole: Post-systolic relaxation of the HEART, especially the HEART VENTRICLES.Heart Ventricles: The lower right and left chambers of the heart. The right ventricle pumps venous BLOOD into the LUNGS and the left ventricle pumps oxygenated blood into the systemic arterial circulation.Indomethacin: A non-steroidal anti-inflammatory agent (NSAID) that inhibits the enzyme cyclooxygenase necessary for the formation of prostaglandins and other autacoids. It also inhibits the motility of polymorphonuclear leukocytes.Muscle, Smooth, Vascular: The nonstriated involuntary muscle tissue of blood vessels.Cardiac Output: The volume of BLOOD passing through the HEART per unit of time. It is usually expressed as liters (volume) per minute so as not to be confused with STROKE VOLUME (volume per beat).Cardiac Pacing, Artificial: Regulation of the rate of contraction of the heart muscles by an artificial pacemaker.Adrenergic beta-Antagonists: Drugs that bind to but do not activate beta-adrenergic receptors thereby blocking the actions of beta-adrenergic agonists. Adrenergic beta-antagonists are used for treatment of hypertension, cardiac arrhythmias, angina pectoris, glaucoma, migraine headaches, and anxiety.Nitrites: Salts of nitrous acid or compounds containing the group NO2-. The inorganic nitrites of the type MNO2 (where M=metal) are all insoluble, except the alkali nitrites. The organic nitrites may be isomeric, but not identical with the corresponding nitro compounds. (Grant & Hackh's Chemical Dictionary, 5th ed)Ultrasonography, Interventional: The use of ultrasound to guide minimally invasive surgical procedures such as needle ASPIRATION BIOPSY; DRAINAGE; etc. Its widest application is intravascular ultrasound imaging but it is useful also in urology and intra-abdominal conditions.NG-Nitroarginine Methyl Ester: A non-selective inhibitor of nitric oxide synthase. It has been used experimentally to induce hypertension.Endothelin-1: A 21-amino acid peptide produced in a variety of tissues including endothelial and vascular smooth-muscle cells, neurons and astrocytes in the central nervous system, and endometrial cells. It acts as a modulator of vasomotor tone, cell proliferation, and hormone production. (N Eng J Med 1995;333(6):356-63)Calcinosis: Pathologic deposition of calcium salts in tissues.Arginine: An essential amino acid that is physiologically active in the L-form.Predictive Value of Tests: In screening and diagnostic tests, the probability that a person with a positive test is a true positive (i.e., has the disease), is referred to as the predictive value of a positive test; whereas, the predictive value of a negative test is the probability that the person with a negative test does not have the disease. Predictive value is related to the sensitivity and specificity of the test.Coronary Artery Bypass, Off-Pump: Coronary artery bypass surgery on a beating HEART without a CARDIOPULMONARY BYPASS (diverting the flow of blood from the heart and lungs through an oxygenator).Myocardial Revascularization: The restoration of blood supply to the myocardium. (From Dorland, 28th ed)Angina, Unstable: Precordial pain at rest, which may precede a MYOCARDIAL INFARCTION.Case-Control Studies: Studies which start with the identification of persons with a disease of interest and a control (comparison, referent) group without the disease. The relationship of an attribute to the disease is examined by comparing diseased and non-diseased persons with regard to the frequency or levels of the attribute in each group.Enzyme Inhibitors: Compounds or agents that combine with an enzyme in such a manner as to prevent the normal substrate-enzyme combination and the catalytic reaction.Angiotensin-Converting Enzyme Inhibitors: A class of drugs whose main indications are the treatment of hypertension and heart failure. They exert their hemodynamic effect mainly by inhibiting the renin-angiotensin system. They also modulate sympathetic nervous system activity and increase prostaglandin synthesis. They cause mainly vasodilation and mild natriuresis without affecting heart rate and contractility.Hypertension: Persistently high systemic arterial BLOOD PRESSURE. Based on multiple readings (BLOOD PRESSURE DETERMINATION), hypertension is currently defined as when SYSTOLIC PRESSURE is consistently greater than 140 mm Hg or when DIASTOLIC PRESSURE is consistently 90 mm Hg or more.Tomography, X-Ray Computed: Tomography using x-ray transmission and a computer algorithm to reconstruct the image.Platelet Aggregation Inhibitors: Drugs or agents which antagonize or impair any mechanism leading to blood platelet aggregation, whether during the phases of activation and shape change or following the dense-granule release reaction and stimulation of the prostaglandin-thromboxane system.Norepinephrine: Precursor of epinephrine that is secreted by the adrenal medulla and is a widespread central and autonomic neurotransmitter. Norepinephrine is the principal transmitter of most postganglionic sympathetic fibers and of the diffuse projection system in the brain arising from the locus ceruleus. It is also found in plants and is used pharmacologically as a sympathomimetic.Risk Assessment: The qualitative or quantitative estimation of the likelihood of adverse effects that may result from exposure to specified health hazards or from the absence of beneficial influences. (Last, Dictionary of Epidemiology, 1988)Potassium Channels: Cell membrane glycoproteins that are selectively permeable to potassium ions. At least eight major groups of K channels exist and they are made up of dozens of different subunits.Enterohepatic Circulation: Recycling through liver by excretion in bile, reabsorption from intestines (INTESTINAL REABSORPTION) into portal circulation, passage back into liver, and re-excretion in bile.Rats, Wistar: A strain of albino rat developed at the Wistar Institute that has spread widely at other institutions. This has markedly diluted the original strain.Retrospective Studies: Studies used to test etiologic hypotheses in which inferences about an exposure to putative causal factors are derived from data relating to characteristics of persons under study or to events or experiences in their past. The essential feature is that some of the persons under study have the disease or outcome of interest and their characteristics are compared with those of unaffected persons.Chest Pain: Pressure, burning, or numbness in the chest.Cerebrovascular Circulation: The circulation of blood through the BLOOD VESSELS of the BRAIN.Severity of Illness Index: Levels within a diagnostic group which are established by various measurement criteria applied to the seriousness of a patient's disorder.Exercise Test: Controlled physical activity which is performed in order to allow assessment of physiological functions, particularly cardiovascular and pulmonary, but also aerobic capacity. Maximal (most intense) exercise is usually required but submaximal exercise is also used.Dipyridamole: A phosphodiesterase inhibitor that blocks uptake and metabolism of adenosine by erythrocytes and vascular endothelial cells. Dipyridamole also potentiates the antiaggregating action of prostacyclin. (From AMA Drug Evaluations Annual, 1994, p752)Sensitivity and Specificity: Binary classification measures to assess test results. Sensitivity or recall rate is the proportion of true positives. Specificity is the probability of correctly determining the absence of a condition. (From Last, Dictionary of Epidemiology, 2d ed)Splanchnic Circulation: The circulation of blood through the BLOOD VESSELS supplying the abdominal VISCERA.Placental Circulation: The circulation of BLOOD, of both the mother and the FETUS, through the PLACENTA.Prognosis: A prediction of the probable outcome of a disease based on a individual's condition and the usual course of the disease as seen in similar situations.Plaque, Atherosclerotic: Lesions formed within the walls of ARTERIES.Cardiovascular Agents: Agents that affect the rate or intensity of cardiac contraction, blood vessel diameter, or blood volume.Blood Circulation Time: Determination of the shortest time interval between the injection of a substance in the vein and its arrival at some distant site in sufficient concentration to produce a recognizable end result. It represents approximately the inverse of the average velocity of blood flow between two points.Recurrence: The return of a sign, symptom, or disease after a remission.Fractional Flow Reserve, Myocardial: The ratio of maximum blood flow to the MYOCARDIUM with CORONARY STENOSIS present, to the maximum equivalent blood flow without stenosis. The measurement is commonly used to verify borderline stenosis of CORONARY ARTERIES.Mucocutaneous Lymph Node Syndrome: An acute, febrile, mucocutaneous condition accompanied by swelling of cervical lymph nodes in infants and young children. The principal symptoms are fever, congestion of the ocular conjunctivae, reddening of the lips and oral cavity, protuberance of tongue papillae, and edema or erythema of the extremities.Ticlopidine: An effective inhibitor of platelet aggregation commonly used in the placement of STENTS in CORONARY ARTERIES.Tomography, Emission-Computed, Single-Photon: A method of computed tomography that uses radionuclides which emit a single photon of a given energy. The camera is rotated 180 or 360 degrees around the patient to capture images at multiple positions along the arc. The computer is then used to reconstruct the transaxial, sagittal, and coronal images from the 3-dimensional distribution of radionuclides in the organ. The advantages of SPECT are that it can be used to observe biochemical and physiological processes as well as size and volume of the organ. The disadvantage is that, unlike positron-emission tomography where the positron-electron annihilation results in the emission of 2 photons at 180 degrees from each other, SPECT requires physical collimation to line up the photons, which results in the loss of many available photons and hence degrades the image.Multivariate Analysis: A set of techniques used when variation in several variables has to be studied simultaneously. In statistics, multivariate analysis is interpreted as any analytic method that allows simultaneous study of two or more dependent variables.Cohort Studies: Studies in which subsets of a defined population are identified. These groups may or may not be exposed to factors hypothesized to influence the probability of the occurrence of a particular disease or other outcome. Cohorts are defined populations which, as a whole, are followed in an attempt to determine distinguishing subgroup characteristics.Multidetector Computed Tomography: Types of spiral computed tomography technology in which multiple slices of data are acquired simultaneously improving the resolution over single slice acquisition technology.Aspirin: The prototypical analgesic used in the treatment of mild to moderate pain. It has anti-inflammatory and antipyretic properties and acts as an inhibitor of cyclooxygenase which results in the inhibition of the biosynthesis of prostaglandins. Aspirin also inhibits platelet aggregation and is used in the prevention of arterial and venous thrombosis. (From Martindale, The Extra Pharmacopoeia, 30th ed, p5)Postoperative Complications: Pathologic processes that affect patients after a surgical procedure. They may or may not be related to the disease for which the surgery was done, and they may or may not be direct results of the surgery.Cardiopulmonary Bypass: Diversion of the flow of blood from the entrance of the right atrium directly to the aorta (or femoral artery) via an oxygenator thus bypassing both the heart and lungs.Acute Disease: Disease having a short and relatively severe course.Chi-Square Distribution: A distribution in which a variable is distributed like the sum of the squares of any given independent random variable, each of which has a normal distribution with mean of zero and variance of one. The chi-square test is a statistical test based on comparison of a test statistic to a chi-square distribution. The oldest of these tests are used to detect whether two or more population distributions differ from one another.Sinus of Valsalva: The dilatation of the aortic wall behind each of the cusps of the aortic valve.Liver Circulation: The circulation of BLOOD through the LIVER.Cineangiography: Motion pictures of the passage of contrast medium through blood vessels.Myocardial Perfusion Imaging: The creation and display of functional images showing where the blood is flowing into the MYOCARDIUM by following over time the distribution of tracers injected into the blood stream.Mammary Arteries: Arteries originating from the subclavian or axillary arteries and distributing to the anterior thoracic wall, mediastinal structures, diaphragm, pectoral muscles and mammary gland.Vascular Calcification: Deposition of calcium into the blood vessel structures. Excessive calcification of the vessels are associated with ATHEROSCLEROTIC PLAQUES formation particularly after MYOCARDIAL INFARCTION (see MONCKEBERG MEDIAL CALCIFIC SCLEROSIS) and chronic kidney diseases which in turn increase VASCULAR STIFFNESS.Ergonovine: An ergot alkaloid (ERGOT ALKALOIDS) with uterine and VASCULAR SMOOTH MUSCLE contractile properties.Contrast Media: Substances used to allow enhanced visualization of tissues.Incidence: The number of new cases of a given disease during a given period in a specified population. It also is used for the rate at which new events occur in a defined population. It is differentiated from PREVALENCE, which refers to all cases, new or old, in the population at a given time.Radial Artery: The direct continuation of the brachial trunk, originating at the bifurcation of the brachial artery opposite the neck of the radius. Its branches may be divided into three groups corresponding to the three regions in which the vessel is situated, the forearm, wrist, and hand.Logistic Models: Statistical models which describe the relationship between a qualitative dependent variable (that is, one which can take only certain discrete values, such as the presence or absence of a disease) and an independent variable. A common application is in epidemiology for estimating an individual's risk (probability of a disease) as a function of a given risk factor.Magnetic Resonance Angiography: Non-invasive method of vascular imaging and determination of internal anatomy without injection of contrast media or radiation exposure. The technique is used especially in CEREBRAL ANGIOGRAPHY as well as for studies of other vascular structures.Stroke Volume: The amount of BLOOD pumped out of the HEART per beat, not to be confused with cardiac output (volume/time). It is calculated as the difference between the end-diastolic volume and the end-systolic volume.Feasibility Studies: Studies to determine the advantages or disadvantages, practicability, or capability of accomplishing a projected plan, study, or project.Hypercholesterolemia: A condition with abnormally high levels of CHOLESTEROL in the blood. It is defined as a cholesterol value exceeding the 95th percentile for the population.Cholesterol: The principal sterol of all higher animals, distributed in body tissues, especially the brain and spinal cord, and in animal fats and oils.Constriction, Pathologic: The condition of an anatomical structure's being constricted beyond normal dimensions.Angiography: Radiography of blood vessels after injection of a contrast medium.Swine, Miniature: Genetically developed small pigs for use in biomedical research. There are several strains - Yucatan miniature, Sinclair miniature, and Minnesota miniature.Syndrome: A characteristic symptom complex.Diabetic Angiopathies: VASCULAR DISEASES that are associated with DIABETES MELLITUS.Angina, Stable: Persistent and reproducible chest discomfort usually precipitated by a physical exertion that dissipates upon cessation of such an activity. The symptoms are manifestations of MYOCARDIAL ISCHEMIA.Disease Models, Animal: Naturally occurring or experimentally induced animal diseases with pathological processes sufficiently similar to those of human diseases. They are used as study models for human diseases.Reproducibility of Results: The statistical reproducibility of measurements (often in a clinical context), including the testing of instrumentation or techniques to obtain reproducible results. The concept includes reproducibility of physiological measurements, which may be used to develop rules to assess probability or prognosis, or response to a stimulus; reproducibility of occurrence of a condition; and reproducibility of experimental results.C-Reactive Protein: A plasma protein that circulates in increased amounts during inflammation and after tissue damage.Tomography, Spiral Computed: Computed tomography where there is continuous X-ray exposure to the patient while being transported in a spiral or helical pattern through the beam of irradiation. This provides improved three-dimensional contrast and spatial resolution compared to conventional computed tomography, where data is obtained and computed from individual sequential exposures.Cholesterol, LDL: Cholesterol which is contained in or bound to low density lipoproteins (LDL), including CHOLESTEROL ESTERS and free cholesterol.Isosorbide Dinitrate: A vasodilator used in the treatment of ANGINA PECTORIS. Its actions are similar to NITROGLYCERIN but with a slower onset of action.Thrombosis: Formation and development of a thrombus or blood clot in the blood vessel.Hydroxymethylglutaryl-CoA Reductase Inhibitors: Compounds that inhibit HMG-CoA reductases. They have been shown to directly lower cholesterol synthesis.Dobutamine: A catecholamine derivative with specificity for BETA-1 ADRENERGIC RECEPTORS. It is commonly used as a cardiotonic agent after CARDIAC SURGERY and during DOBUTAMINE STRESS ECHOCARDIOGRAPHY.Heart Arrest: Cessation of heart beat or MYOCARDIAL CONTRACTION. If it is treated within a few minutes, heart arrest can be reversed in most cases to normal cardiac rhythm and effective circulation.Saphenous Vein: The vein which drains the foot and leg.Thallium Radioisotopes: Unstable isotopes of thallium that decay or disintegrate emitting radiation. Tl atoms with atomic weights 198-202, 204, and 206-210 are thallium radioisotopes.Proportional Hazards Models: Statistical models used in survival analysis that assert that the effect of the study factors on the hazard rate in the study population is multiplicative and does not change over time.Registries: The systems and processes involved in the establishment, support, management, and operation of registers, e.g., disease registers.Hemorrhage: Bleeding or escape of blood from a vessel.Angioscopy: Endoscopic examination, therapy or surgery performed on the interior of blood vessels.Age Factors: Age as a constituent element or influence contributing to the production of a result. It may be applicable to the cause or the effect of a circumstance. It is used with human or animal concepts but should be differentiated from AGING, a physiological process, and TIME FACTORS which refers only to the passage of time.Cardiovascular Diseases: Pathological conditions involving the CARDIOVASCULAR SYSTEM including the HEART; the BLOOD VESSELS; or the PERICARDIUM.Pulmonary Artery: The short wide vessel arising from the conus arteriosus of the right ventricle and conveying unaerated blood to the lungs.Ventricular Dysfunction, Left: A condition in which the LEFT VENTRICLE of the heart was functionally impaired. This condition usually leads to HEART FAILURE; MYOCARDIAL INFARCTION; and other cardiovascular complications. Diagnosis is made by measuring the diminished ejection fraction and a depressed level of motility of the left ventricular wall.Graft Occlusion, Vascular: Obstruction of flow in biological or prosthetic vascular grafts.Lipids: A generic term for fats and lipoids, the alcohol-ether-soluble constituents of protoplasm, which are insoluble in water. They comprise the fats, fatty oils, essential oils, waxes, phospholipids, glycolipids, sulfolipids, aminolipids, chromolipids (lipochromes), and fatty acids. (Grant & Hackh's Chemical Dictionary, 5th ed)Sex Factors: Maleness or femaleness as a constituent element or influence contributing to the production of a result. It may be applicable to the cause or effect of a circumstance. It is used with human or animal concepts but should be differentiated from SEX CHARACTERISTICS, anatomical or physiological manifestations of sex, and from SEX DISTRIBUTION, the number of males and females in given circumstances.Hospital Mortality: A vital statistic measuring or recording the rate of death from any cause in hospitalized populations.Arteriosclerosis: Thickening and loss of elasticity of the walls of ARTERIES of all sizes. There are many forms classified by the types of lesions and arteries involved, such as ATHEROSCLEROSIS with fatty lesions in the ARTERIAL INTIMA of medium and large muscular arteries.Heart Arrest, Induced: A procedure to stop the contraction of MYOCARDIUM during HEART SURGERY. It is usually achieved with the use of chemicals (CARDIOPLEGIC SOLUTIONS) or cold temperature (such as chilled perfusate).Cholesterol, HDL: Cholesterol which is contained in or bound to high-density lipoproteins (HDL), including CHOLESTEROL ESTERS and free cholesterol.Tunica Intima: The innermost layer of an artery or vein, made up of one layer of endothelial cells and supported by an internal elastic lamina.Regression Analysis: Procedures for finding the mathematical function which best describes the relationship between a dependent variable and one or more independent variables. In linear regression (see LINEAR MODELS) the relationship is constrained to be a straight line and LEAST-SQUARES ANALYSIS is used to determine the best fit. In logistic regression (see LOGISTIC MODELS) the dependent variable is qualitative rather than continuously variable and LIKELIHOOD FUNCTIONS are used to find the best relationship. In multiple regression, the dependent variable is considered to depend on more than a single independent variable.Thrombolytic Therapy: Use of infusions of FIBRINOLYTIC AGENTS to destroy or dissolve thrombi in blood vessels or bypass grafts.Injections, Intra-Arterial: Delivery of drugs into an artery.Microvascular Angina: ANGINA PECTORIS or angina-like chest pain with a normal coronary arteriogram and positive EXERCISE TEST. The cause of the syndrome is unknown. While its recognition is of clinical importance, its prognosis is excellent. (Braunwald, Heart Disease, 4th ed, p1346; Jablonski Dictionary of Syndromes & Eponymic Diseases, 2d ed). It is different from METABOLIC SYNDROME X, a syndrome characterized by INSULIN RESISTANCE and HYPERINSULINEMIA, that has increased risk for cardiovascular disease.Myocardial Bridging: A malformation that is characterized by a muscle bridge over a segment of the CORONARY ARTERIES. Systolic contractions of the muscle bridge can lead to narrowing of coronary artery; coronary compression; MYOCARDIAL ISCHEMIA; MYOCARDIAL INFARCTION; and SUDDEN CARDIAC DEATH.Stroke: A group of pathological conditions characterized by sudden, non-convulsive loss of neurological function due to BRAIN ISCHEMIA or INTRACRANIAL HEMORRHAGES. Stroke is classified by the type of tissue NECROSIS, such as the anatomic location, vasculature involved, etiology, age of the affected individual, and hemorrhagic vs. non-hemorrhagic nature. (From Adams et al., Principles of Neurology, 6th ed, pp777-810)Veins: The vessels carrying blood away from the capillary beds.Odds Ratio: The ratio of two odds. The exposure-odds ratio for case control data is the ratio of the odds in favor of exposure among cases to the odds in favor of exposure among noncases. The disease-odds ratio for a cohort or cross section is the ratio of the odds in favor of disease among the exposed to the odds in favor of disease among the unexposed. The prevalence-odds ratio refers to an odds ratio derived cross-sectionally from studies of prevalent cases.Cardiotonic Agents: Agents that have a strengthening effect on the heart or that can increase cardiac output. They may be CARDIAC GLYCOSIDES; SYMPATHOMIMETICS; or other drugs. They are used after MYOCARDIAL INFARCT; CARDIAC SURGICAL PROCEDURES; in SHOCK; or in congestive heart failure (HEART FAILURE).Vascular Patency: The degree to which BLOOD VESSELS are not blocked or obstructed.Dilatation, Pathologic: The condition of an anatomical structure's being dilated beyond normal dimensions.Atherosclerosis: A thickening and loss of elasticity of the walls of ARTERIES that occurs with formation of ATHEROSCLEROTIC PLAQUES within the ARTERIAL INTIMA.Arterioles: The smallest divisions of the arteries located between the muscular arteries and the capillaries.Risk: The probability that an event will occur. It encompasses a variety of measures of the probability of a generally unfavorable outcome.Diabetes Complications: Conditions or pathological processes associated with the disease of diabetes mellitus. Due to the impaired control of BLOOD GLUCOSE level in diabetic patients, pathological processes develop in numerous tissues and organs including the EYE, the KIDNEY, the BLOOD VESSELS, and the NERVE TISSUE.Assisted Circulation: Pumping that aids the natural activity of the heart. (Dorland, 27th ed)

Phasic right coronary artery blood flow in conscious dogs with normal and elevated right ventricular pressures. (1/5587)

We studied phasic right coronary blood flow in well trained normal dogs and dogs with pulmonic stenosis. We installed electromagnetic flow transducers and pressure tubes under anesthesia to monitor right coronary blood flow, cardiac output, central aortic blood pressure, and right ventribular pressure. In normotensive dogs, systolic flow amplitude equaled early diastolic flow levels. The ratio of systolic to diastolic flow at rest was substantially greater in the right coronary bed (36+/-1.3%) than in the left circumflex bed (13+/-3.6%). Right diastolid flow runoff, including the cove late in diastole, resembled left circumflex runoff. Blood flow to the normotensive right (37+/-1.1 ml/min 100(-1) g) and the left (35+/-1.0 ml/min(-1) g) ventricular myocardium indicated equal perfusion of both cardiac walls. Throttling of systolic flow was related directly to the right ventricular systolic pressure level in the dogs with pulmonic stenosis. Retrograde systolic flow occurred in severe right ventricular hypertension. The late diastolic runoff pattern in dogs with pulmonic stenosis appeared the same as for the normotensive dogs. We obtained systolic to diastolic flow ratios of 1/3 the value of normotensive hearts in high and severe pulmonic hypertension. Electrocardiograms and studies of pathology suggested restricted blood flow to the inner layers of the right myocardium in the dogs with severe and high right ventricular hypertension. Normotensive and hypertensive peak hyperemic flow responses were similar, except for an increased magnitude of diastolic flow, with proportionately less systolic flow in hypertensive states.  (+info)

The effect of cardiac contraction on collateral resistance in the canine heart. (2/5587)

We determined whether the coronary collateral vessels develop an increased resistance to blood flow during systole as does the cognate vascular bed. Collateral resistance was estimated by measuring retrograde flow rate from a distal branch of the left anterior descending coronary artery while the main left coronary artery was perfused at a constant pressure. Retrograde flow rate was measured before and during vagal arrest. We found that in 10 dogs the prolonged diastole experienced when the heart was stopped caused no significant change in the retrograde flow rate, which indicated that systole has little effect on the collateral resistance. However, when left ventricular end-diastolic pressure was altered by changing afterload or contractility, a direct relationship between end-diastolic pressure and collateral resistance was noted.  (+info)

Endogenous plasma endothelin concentrations and coronary circulation in patients with mild dilated cardiomyopathy. (3/5587)

OBJECTIVE: To determine whether increased plasma concentrations of endothelin-1 (ET-1) and big endothelin (BET) play a role in the regulation of coronary circulation in patients with idiopathic dilated cardiomyopathy (IDCM). SETTING: Tertiary referral centre for cardiac diseases. PATIENTS: Fourteen patients (eight male/six female; mean (SD) age 59 (9) years) with IDCM (ejection fraction 36 (9)%) and five normotensive subjects (two male/three female; age 52 (7) years) serving as controls were studied. METHODS: Functional status was classified according to New York Heart Association (NYHA) class. Endogenous ET-1 and BET plasma concentrations from the aorta and the coronary sinus were determined by radioimmunoassay. Coronary blood flow, using the inert chromatographic argon method, myocardial oxygen consumption, and coronary sinus oxygen content under basal conditions were determined. RESULTS: In the aorta, mean (SD) concentrations of ET-1 (IDCM 0.76 (0.25) v controls 0.31 (0.06) fmol/ml; p = 0.002) and BET (IDCM 3.58 (1.06) v controls 2.11 (0.58) fmol/ml; p = 0.014) were increased in patients with IDCM. Aortic ET-1 concentrations correlated positively with NYHA class (r = 0. 731; p < 0.001), myocardial oxygen consumption (r = 0.749; p < 0. 001), and coronary blood flow (r = 0.645; p = 0.003), but inversely with coronary sinus oxygen content (r = -0.633; p = 0.004), which was significantly decreased in IDCM patients (IDCM 4.68 (1.05) v controls 6.70 (1.06) vol%; p = 0.003). CONCLUSIONS: The coronary circulation in patients with IDCM is exposed to an increased endothelin load. ET-1 concentrations correlate with functional deterioration. A decrease of the coronary sinus content of oxygen suggests a mismatch between coronary blood flow and metabolic demand. Thus, ET-1 might be a marker of a disequilibrium between myocardial oxygen demand and coronary blood flow in IDCM.  (+info)

Prognostic value of myocardial perfusion imaging in patients with high exercise tolerance. (4/5587)

BACKGROUND: Although high exercise tolerance is associated with an excellent prognosis, the significance of abnormal myocardial perfusion imaging (MPI) in patients with high exercise tolerance has not been established. This study retrospectively compares the utility of MPI and exercise ECG (EECG) in these patients. METHODS AND RESULTS: Of 388 consecutive patients who underwent exercise MPI and reached at least Bruce stage IV, 157 (40.5%) had abnormal results and 231 (59.5%) had normal results. Follow-up was performed at 18+/-2.7 months. Adverse events, including revascularization, myocardial infarction, and cardiac death, occurred in 40 patients. Nineteen patients had revascularization related to the MPI results or the patient's condition at the time of MPI and were not included in further analysis. Seventeen patients (12.2%) with abnormal MPI and 4 (1.7%) with normal MPI had adverse cardiac events (P<0.001). Cox proportional-hazards regression analysis showed that MPI was an excellent predictor of cardiac events (global chi2=13.2; P<0.001; relative risk=8; 95% CI=3 to 23) but EECG had no predictive power (global chi2=0.05; P=0.8; relative risk=1; 95% CI=0.4 to 3.0). The addition of Duke's treadmill score risk categories did not improve the predictive power of EECG (global chi2=0.17). The predictive power of the combination of EECG (including Duke score categories) and MPI was no better than that of MPI alone (global chi2=13.5). CONCLUSIONS: Unlike EECG, MPI is an excellent prognostic indicator for adverse cardiac events in patients with known or suspected CAD and high exercise tolerance.  (+info)

Usefulness of fractional flow reserve to predict clinical outcome after balloon angioplasty. (5/5587)

BACKGROUND: After regular coronary balloon angioplasty, it would be helpful to identify those patients who have a low cardiac event rate. Coronary angiography alone is not sensitive enough for that purpose, but it has been suggested that the combination of optimal angiographic and optimal functional results indicates a low restenosis chance. Pressure-derived myocardial fractional flow reserve (FFR) is an index of the functional severity of the residual epicardial lesion and could be useful for that purpose. METHODS AND RESULTS: In 60 consecutive patients with single-vessel disease, balloon angioplasty was performed by use of a pressure instead of a regular guide wire. Both quantitative coronary angiography (QCA) and measurement of FFR were performed 15 minutes after the procedure. A successful angioplasty result, defined as a residual diameter stenosis (DS) <50%, was achieved in 58 patients. In these patients, DS and FFR, measured 15 minutes after PTCA, were analyzed in relation to clinical outcome. In those 26 patients with both optimal angiographic (residual DS by QCA /=0.90) results, event-free survival rates at 6, 12, and 24 months were 92+/-5%, 92+/-5%, and 88+/-6%, respectively, versus 72+/-8%, 69+/-8%, and 59+/-9%, respectively, in the remaining 32 patients in whom the angiographic or functional result or both were suboptimal (P=0.047, P=0.028, and P=0.014, respectively). CONCLUSIONS: In patients with a residual DS /=0.90, clinical outcome up to 2 years is excellent. Therefore, there is a complementary value of coronary angiography and coronary pressure measurement in the evaluation of PTCA result.  (+info)

Simultaneous assessment of effects of coronary vasodilators on the coronary blood flow and the myocardial contractility by using the blood-perfused canine papillary muscle. (6/5587)

Effects of 6 coronary vasodilators on the coronary blood flow and the contractile force of the ventricular muscle were examined simultaneously by injecting these drugs to the arterially blood-perfused canine papillary muscle preparation. All compounds produced a dose-dependent increase in blood flow rate, and relative potencies determined on the basis of doses producing a 100% increase in blood flow rate, ED100, were in the descending order : nifedipine greater than verapamil greater than diltiazem greater than dilazep greater than dipyridamole greater than carbochromen, and approximately 1 : 1/12 : 1/26 : 1/100 : 1/300 : 1/500. All drugs except for dipyridamole caused a dose-dependent decrease in the developed tension of the papillary muscle, although nifedipine and diltiazem in low doses produced a slight increase. Relative potencies determined on the basis of doses producing a 50% decrease in developed tension, ID50, were as follows: nifedipine (1), verapamil (1/13), diltiazem (1/40), dilazep (1/100), and carbochromen (1/270). Ratios of the ID50 to ED100 were as follows: diltiazem (5.2), nifedipine (3.5), verapamil (3.5), dilazep (2.5), and carbochromen (1.8). The higher the value the more predominant on the coronary vascular bed or the less depressant on the myocardial contractility were their actions.  (+info)

A comparison of an A1 adenosine receptor agonist (CVT-510) with diltiazem for slowing of AV nodal conduction in guinea-pig. (7/5587)

1. The purpose of this study was to compare the pharmacological properties (i.e. the AV nodal depressant, vasodilator, and inotropic effects) of two AV nodal blocking agents belonging to different drug classes; a novel A1 adenosine receptor (A1 receptor) agonist, N-(3(R)-tetrahydrofuranyl)-6-aminopurine riboside (CVT-510), and the prototypical calcium channel blocker diltiazem. 2. In the atrial-paced isolated heart, CVT-510 was approximately 5 fold more potent to prolong the stimulus-to-His bundle (S-H interval), a measure of slowing AV nodal conduction (EC50 = 41 nM) than to increase coronary conductance (EC50 = 200 nM). At concentrations of CVT-510 (40 nM) and diltiazem (1 microM) that caused equal prolongation of S-H interval (approximately 10 ms), diltiazem, but not CVT-510, significantly reduced left ventricular developed pressure (LVP) and markedly increased coronary conductance. CVT-510 shortened atrial (EC50 = 73 nM) but not the ventricular monophasic action potentials (MAP). 3. In atrial-paced anaesthetized guinea-pigs, intravenous infusions of CVT-510 and diltiazem caused nearly equal prolongations of P-R interval. However, diltiazem, but not CVT-510, significantly reduced mean arterial blood pressure. 4. Both CVT-510 and diltiazem prolonged S-H interval, i.e., slowed AV nodal conduction. However, the A1 receptor-selective agonist CVT-510 did so without causing the negative inotropic, vasodilator, and hypotensive effects associated with diltiazem. Because CVT-510 did not affect the ventricular action potential, it is unlikely that this agonist will have a proarrythmic action in ventricular myocardium.  (+info)

Comparison of quantitative coronary angiography, intravascular ultrasound, and coronary pressure measurement to assess optimum stent deployment. (8/5587)

BACKGROUND: Although intravascular ultrasound (IVUS) is the present standard for the evaluation of optimum stent deployment, this technique is expensive and not routinely feasible in most catheterization laboratories. Coronary pressure-derived myocardial fractional flow reserve (FFRmyo) is an easy, cheap, and rapidly obtainable index that is specific for the conductance of the epicardial coronary artery. In this study, we investigated the usefulness of coronary pressure measurement to predict optimum and suboptimum stent deployment. METHODS AND RESULTS: In 30 patients, a Wiktor-i stent was implanted at different inflation pressures, starting at 6 atm and increasing step by step to 8, 10, 12, and 14 atm, if necessary. After every step, stent deployment was evaluated by quantitative coronary angiography (QCA), IVUS, and coronary pressure measurement. If any of the 3 techniques did not yield an optimum result, the next inflation was performed, and all 3 investigational modalities were repeated until optimum stent deployment was present by all of them or until the treating physician decided to accept the result. Optimum deployment according to QCA was finally achieved in 24 patients, according to IVUS in 17 patients, and also according to coronary pressure measurement in 17 patients. During the step-up, a total of 81 paired IVUS and coronary pressure measurements were performed, of which 91% yielded concordant results (ie, either an optimum or a suboptimum expansion of the stent by both techniques, P<0.00001). On the contrary, QCA showed a low concordance rate with IVUS and FFRmyo (48% and 46%, respectively). CONCLUSIONS: In this study, using a coil stent, both IVUS and coronary pressure measurement were of similar value with respect to the assessment of optimum stent deployment. Therefore, coronary pressure measurement can be used as a cheap and rapid alternative to IVUS for that purpose.  (+info)

Chronotropic doses of dobutamine have been shown to increase transmural WT, even in perfusion beds subtended by coronary stenoses that range from 30% to 80% in diameter (8). If the stenosis is more severe or if higher doses of dobutamine are used, WT becomes abnormal (2). Transmural myocardial blood flow responses, however, are different, with decreases in myocardial blood flow observed even in milder non-flow limiting stenoses (2). As the stenosis becomes more severe, a marked decrease in subendocardial blood flow has been observed (9-11), with a marked decrease in endocardial/epicardial flow ratios. In this study, RTMCE detected this decrease in endocardial to epicardial blood flow abnormality in 45 of the 55 patients with LAD stenoses ,50%.. Another pertinent pharmacologic property of dobutamine is its ability to recruit the subepicardial layers to thicken. The subendocardium is responsible for over 40% of WT under resting conditions (12,13), and thus resting WT might be abnormal even when ...
Background. Experimental studies on the effects of alpha2-adrenoceptors on regional coronary blood flow in normal and ischemic myocardium are highly controversial. A beneficial effect on regional ischemic myocardium has been demonstrated in different animal preparations with either alpha2-adrenoceptor blockade or stimulation. Animal studies also demonstrated that postsynaptic alpha2-adrenoceptors mediate vasoconstriction in coronary and femoral vascular beds. The aims of the study were 1) to investigate the effects of regional alpha2-adrenoceptor stimulation on regional coronary blood flow in subjects with angiographically normal coronary arteries, 2) to assess the effect of alpha2-adrenoceptor blockade on coronary circulation in control subjects, and 3) to examine the influence of atherosclerosis on coronary blood flow response to alpha2-adrenoceptor blockade. Methods and Results. The effect of regional administration of BHT 933 (a selective alpha2-adrenoceptor agonist) was studied in eight ...
Previous reports have indicated that hypertensive patients who have angina-like chest pain and normal coronary arteriograms have reduced coronary flow velocity reserve (CFVR) levels. In addition, elevated plasma endothelin-1 (ET-1) levels have been reported to be associated with microvascular angina. The purpose of this study was to evaluate the plasma ET-1 levels and CFVR in patients with chest pain but without coronary artery disease (CAD). A total of 66 patients were included in this study. CAD was ruled out by exercise stress test or coronary angiogram. Plasma ET-1 and CFVR measurements were performed in patients with (n=35) and without (n=31) a history of angina-like chest pain. CFVR was measured using adenosine-triphosphate stress transthoracic Doppler echocardiography. The mean ET-1 level was significantly higher and the CFVR was significantly lower in patients in the symptomatic group than in those in the asymptomatic group (ET-1: 3.85±1.24 pg/ml vs. 2.98±1.27 pg/ml, CFVR: 2.26±0.48 vs. 2.77
Coronary flow velocity reserve (CFVR) measured by transthoracic Doppler echocardiography of the LAD is used to assess microvascular function but validation studies in clinical settings are lacking. We aimed to assess feasibility, reproducibility and agreement with myocardial flow reserve (MFR) measured by PET in overweight and obese patients. Participants with revascularized coronary artery disease were examined by CFVR. Subgroups were examined by repeated CFVR (reproducibility) or Rubidium-82-PET (agreement). To account for time variation, results were computed for scans performed within a week (1-week) and for all scans regardless of time gap (total) and to account for scar tissue for patients with and without previous myocardial infarction (MI). Eighty-six patients with median BMI 30.9 (IQR 29.4-32.9) kg × m−2 and CFVR 2.29 (1.90-2.63) were included. CFVR was feasible in 83 (97 %) using a contrast agent in 14 %. For reproducibility overall (n = 21) limits of agreement (LOA) were (−0.75;0.71),
The effect of a new coronary vasodilator (Persantin), which produces a marked increase in coronary blood flow (up to 159 per cent in normal animals) without increasing cardiac contractility or cardiac work, has been studied in the experimental animal. This is associated with a marked decrease in coronary resistance. There is an increase in the coronary venous oxygen content and a decrease in the coronary A-V oxygen difference; the cardiac output is only slightly affected. Increase in the coronary blood flow has also been observed in dogs in which coronary in sufficiency has been produced by coronary ligation and by narrowing of the lumen of the coronary artery by the application of casein rings. This was accompanied by no significant increase in cardiac work.. ...
Relief of the coronary obstruction by thrombolysis or percutaneous catheter-based intervention and restoration of normal flow in the culprit artery has been the goal of therapy in patients with acute MI. This analysis shows, however, that acute MI slows flow not only in the culprit artery, but also in the nonculprit artery by 45%. Culprit and nonculprit artery flows were linked, and relief of the residual stenosis in the culprit artery restored flow to the culprit artery, which was the same as in the nonculprit arteries (both 30 frames). Although improved post-PTCA, both culprit and nonculprit artery flows were still 45% slower than normal (21 frames). Multiple variables were associated with slower nonculprit artery flow: slower flow in the associated culprit artery, a larger territory infarcted (e.g., larger diameter culprit arteries with a larger percent of the culprit vessel distal to the stenosis, the absence of collaterals, LAD as the culprit artery), tighter stenoses within the nonculprit ...
To examine the influence of preexistent diabetes mellitus on left ventricular performance and coronary blood flow responses to acute ischemia, mild normoglycemic diabetes was induced in nine mongrel dogs after three doses of alloxan, (20 mg/kg, iv), at monthly intervals. Hemodynamic measurements and coronary blood flow (85Kr clearance) were obtained before and after the onset of ischemia. This was produced by occlusion of the proximal left anterior descending coronary artery via a balloon-type catheter in nine intact anesthetized diabetic dogs and 10 nondiabetic dogs. During the 1st hour of ischemia in the diabetic group, the end-diastolic pressure rose from 7 +/- 1.1 (mean +/- SE) mm Hg to 23.8 +/- 2.3 without a significant increase of end-diastolic volume. In controls end-diastolic pressure rose from 8.6 +/- 1.1 mm Hg to 15.3 +/- 1.4, and end-diastolic volume was significantly increased, so that the ratio of end-diastolic pressure and volume was significantly higher in the diabetic group (P ...
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Apart from evaluating the physiological significance of epicardial stenoses, intracoronary Doppler has become an important tool in patients with suspected microvascular disease. Recent studies report an impaired coronary flow reserve in patients with diabetes mellitus, hypertension and smoking (11,19-22). These findings are attributed to abnormalities in coronary vasomotion. It has been proposed that a coronary flow reserve of less than 2.5 (23) and a CFVR of less than 2.24 (14) in the absence of significant epicardial stenosis is a sign of microvascular dysfunction. Categorizing women in this study according to the cut-off value for CFVR of 2.24 revealed that women with suspected microvascular dysfunction have a significantly increased bAPV, and systolic blood pressure. As these factors may, in part, contribute to the reduction of CFVR, the use of traditional CFVR as an indicator of microvascular dysfunction may not sufficiently discriminate between factors affecting vasodilator reserve and ...
article{2286a0f7-5934-41f8-aed8-94b7a8b75a40, abstract = {Recent studies indicate a severely reduced coronary flow reserve (CFR) in neonates with congenital heart disease. The significance of these studies remains debatable, as the ability of the anatomically normal neonatal heart to increase coronary flow is currently unknown. This study was designed to establish normal values for CFR in newborns after administration of adenosine [pharmacologic CFR (pCFR)] and as induced by acute hypoxemia (reactive CFR). Thirteen mechanically ventilated newborn lambs were studied. Coronary flow velocities were measured in the proximal left anterior descending coronary artery before and after adenosine injection (140 and 280 mug/kg i.v.) using an intracoronary 0.014-in Doppler flow-wire. Measurements were made at normal oxygen saturation (Sao(2)) and during progressive hypoxemia induced by lowering the fraction of inspired oxygen. CFR was defined as the ratio of hyperemic to basal average peak flow velocity. In ...
C Newman, D Hackett, H El-Tamimi, A Maseri, G Davies; Acetylcholine Has Dose-Dependent Bimodal Effects on Coronary Blood Flow in Man. Clin Sci (Lond) 1 January 1988; 74 (s18): 45P. doi: https://doi.org/10.1042/cs074045P. Download citation file:. ...
5-hydroxytryptamine (5-HT)-induced coronary artery responses have both vasoconstriction and vasorelaxation components. The vasoconstrictive effects of 5-HT have been well studied while the mechanism(s) of how 5-HT causes relaxation of coronary arteries has been less investigated. In isolated rat hearts, 5-HT-induced coronary flow increases are partially resistant to the nitric oxide synthase inhibitor Nω-Nitro-L-arginine methyl ester (L-NAME) and are blocked by 5-HT7 receptor antagonists. In the present study, we investigated the role of 5-HT7 receptor in 5-HT-induced coronary flow increases in isolated rat hearts in the absence of L-NAME, and we also evaluated the involvement of endothelium-derived hyperpolarizing factor (EDHF) in 5-HT-induced coronary flow increases in L-NAME-treated hearts with the inhibitors of arachidonic acid metabolism and the blockers of Ca2+-activated K+ channels. In isolated rat hearts, 5-HT and the 5-HT7 receptor agonist 5-carboxamidotryptamine induced coronary flow
Myocardial perfusion imaging (MPI), using single photon emission computed tomography (SPECT) is a validated method for detecting coronary artery disease. Transthoracic Doppler echocardiography (TTDE) of flow at rest and during adenosine provocation has previously been evaluated in selected patient groups. We therefore wanted to compare the diagnostic ability of TTDE in the left anterior descending coronary artery (LAD) to that of MPI in an unselected population of patients with chest pain referred for MPI. Our hypothesis was that TTDE with high accuracy would identify healthy individuals and exclude them from the need for further studies, enabling invasive investigations to be reserved for patients with a high probability of disease. Sixty-nine patients, 44 men and 25 women, age 61 ± 10 years (range 35-82), with a clinical suspicion of stress induced myocardial ischemia, were investigated. TTDE was performed at rest and during adenosine stress for myocardial scintigraphy. We found that coronary flow
This study was designed to examine the relationship between epicardial ST change (EpST) and regional myocardial blood flow (RMBF) following coronary occlusion and extent of myocardial infarction (MI) in awake dogs. Fifteen min and two hr after coronary occlusion simultaneous measurements of EpST and RMBF were made. Six days later histologic MI and RMBF were determined in transmural myocardial samples from each electrode site. Greatest ST elevation occurred at sites of greatest ischemia and MI. However, 15 min after occlusion 29% of sites with greater than 50% MI and 39% of sites with greater than 50% reduction in RMBF did not demonstrate ST elevation greater than 2 mV. There were poor correlations between EpST and MI (r = 0.59) and RMBF (r = 0.57). Comparable relationships were observed two hr after occlusion. In the present study, there were not close quantitative or qualitative relationships between EpST and MI or RMBF. A good correlation was observed between RMBF at two hr and MI (r = 0.89). ...
There is intense controversy as to the mechanisms underlying chronic but reversible left ventricular (LV) ischemic dysfunction. The aim of this study was to investigate the physiology underlying this condition in a canine model of noninfarcted collateral-dependent myocardium. METHODS: Six mongrel dogs were instrumented with ameroid constrictors on the left circumflex and right coronary arteries and a partial occluder on the left anterior descending coronary artery. The animals were followed up for 6 mo. Every 6 wk, measurements of regional wall thickening (M-mode echo), myocardial blood flow ((13)N-ammonia PET), oxygen consumption ((11)C-acetate PET), and glucose uptake ((18)F-FDG PET) were obtained. After 6 mo, myocardial blood flow reserve (during adenosine infusion) and regional contractile reserve (during infusion of a low dose of dobutamine) were also investigated. RESULTS: Following ameroid implantation, regional thickening decreased in the posterior wall (to 34% +/- 13% of baseline; P , ...
Spontaneously hypertensive rats (SHR) demonstrate an elevated minimal coronary vascular resistance by the seventh month of age. In an attempt to determine the role of long-standing hypertension in the etiological process of the elevated minimal coronary vascular resistance, we treated SHR and normotensive Wistar-Kyoto rats (WKY) with the vasodilator hydralazine from the time of weaning (1 month) until they were 7 to 8 months of age. The animals were instrumented 24 hours after their last drug dose and then studied on the following day. Using microspheres we measured myocardial perfusion in conscious rats at rest and during maximal coronary dilation induced with dipyridamole infusion. Hydralazine maintained arterial blood pressures in the normotensive range throughout the experimental period, but had little effect on left ventricular weight/body weight ratios (control SHR = 2.95 +/- 0.07, treated SHR = 2.73 +/- 0.08, control WKY = 2.39 +/- 0.09, mean +/- SEM). In treated SHR, left ventricular ...
TIMI frame count is an alternative to the TIMI flow. Unlike TIMI flow, it offers a quantitative assessment of coronary artery blood flow. TIMI frame count is expressed as the number of frames required for dye to reach a standardized distal landmark in a coronary artery.
The results of the present study confirm previous observations that relate elevated WBC count to adverse clinical outcomes in patients with acute MI and further explore the pathophysiology that underlies this relationship. Several new important observations were made. First, an elevation in WBC count was associated with a resistance to thrombolytic therapy as demonstrated by lower rates of coronary patency at both 60 and 90 minutes after the administration of thrombolytic therapy, as well as an increased thrombus burden in patients with a patent infarct-related artery. This was independent of duration of symptoms, which has also been associated with thromboresistance. Second, elevations in WBC count were associated with impaired microvascular perfusion as demonstrated by a reduction in myocardial perfusion grade. Third, elevation in WBC count was a strong predictor of the subsequent development of CHF independent of epicardial or microvascular coronary blood flow.. In the present study, an ...
The first aim of this thesis was to critically appraise and improve the classification of small cerebellar infarctions and to visualise arterial cerebellar perfusion territories. Although small cerebellar infarcts are traditionally classified into "watershed" or "border zone" perfusion territories, arterial perfusion territories and the border zones in between them are widely variable among subjects. Also, many infarcts do not fit into such a classification system, which hinders its use in clinical practice [1].. We proposed two answers to these limitations. The first was to omit the traditional classification and to classify small cerebellar infarctions according to anatomical location in the cerebellum instead of arterial perfusion territories [1]. The second and more challenging answer was to develop the first imaging technique to visualise cerebellar perfusion territories in vivo [2]. This way, cerebellar infarction may be directly linked with the responsible diseased artery, for instance, ...
TY - JOUR. T1 - Importance of basal nitric oxide synthesis in regulation of myocardial blood flow. AU - Benyó, Zoltán. AU - Kiss, Gergely. AU - Szabo, Csaba. AU - Csáki, Csilla. AU - Kovách, Arisztid G.B.. PY - 1991/1/1. Y1 - 1991/1/1. N2 - Study objective - The aim was to investigate whether basal coronary vascular tone and myocardial perfusion depend upon endothelial nitric oxide (NO) synthesis.Design - Myocardial blood flow and vascular resistance of the left and right ventricles were studied before and after intravenous infusions of either NG-nitro-L-arginine (L-NA), a specific inhibitor of NO synthase, or L-arginine, the precursor of NO synthesis. Radiolabelled microspheres were used to study myocardial blood flow in small tissue sections.Experimental material - 14 anaesthetised male cats, weight 2.1-3.5 kg, were used.Measurements and main results - Measurements were made before and 15 and 40 min after L-NA treatment (30 mg·kg-1 bolus followed by 1 mg·kg-1·min-1 infusion; n=8), and ...
BACKGROUND: Positron emission tomography scanners with retractable septa allow both 3-dimensional (3D) and 2-dimensional (2D) acquisition modes. The study aim was to directly compare 2D and 3D acquisition modes for the evaluation of absolute myocardial blood flow (MBF) over a wide range of flow values. METHODS AND RESULTS: Instrumentation was used in 4 dogs to reduce the left circumflex artery lumen by greater than 75%. During infusion of adenosine, MBF was measured with both 2D and 3D dynamic acquisition and both oxygen 15 water and nitrogen 13 ammonia. Injected activities were 333 MBq and 111 MBq for 2D acquisition and 3D acquisition, respectively. Data were reconstructed by analytic methods, and MBF was assessed by use of an 18-segment model. MBF values ranged from 0.4 to 5.8 mL x g(-1) x min(-1) with O-15 water and from 0.3 to 3.9 mL x g(-1) x min(-1) with N-13 ammonia. No significant differences were observed in absolute MBF values obtained with the 2 acquisition modes, regardless of the ...
Assess the effect of Ticagrelor compared to placebo on the adenosine induced coronary blood flow velocity response by estimating the change in area under the adenosine dose response curve before and after study drug. [ Time Frame: During 6 h at visit 2 ...
p,The effect of the heart rate and myocardial contractile force on the extravascular resistance to blood flow of the left anterior descending coronary artery (LAD) was evaluated in 15 mongrel dogs anesthetized with sodium pentobarbital. The LAD was maximally dilated by intracoronary infusion of adenosine, which precluded the influence of vasomotor tone. Increases in the heart rate and myocardial contractile force decreased coronary blood flow in the absence of a change in coronary perfusion pressure. The changes in mean coronary resistance showed a significant linear relationship to changes in developed tension. The changes in coronary resistance caused by varying the heart rate and contractile force were so small that a normal coronary vascular tree could easily compensate for the increase in resistance. However, it is supposed that with critical stenosis of the vascular tree even a small increase in resistance might cause deleterious effects on coronary blood flow.,/p, ...
The effects of acetylcholine, 10 microgram/kg i.v., were examined in nine conscious dogs on measurements of left ventricular pressure, dP/dt, aortic pressure, heart rate, coronary blood flow, left circumflex external coronary arterial diameter, arterial and coronary sinus O2 content and calculations of late diastolic coronary resistance and left circumflex internal coronary cross-sectional area. In conscious dogs in the absence of autonomic blockade, acetylcholine induced a rapid, transient response characterized by hypotension and peak increases in coronary blood flow (+135 +/- 14%) and coronary sinus O2 content (+5.0 +/- 0.5 volume percent) and decreases in late diastolic coronary resistance (-65 +/- 3%). The peak large coronary arterial effects were observed 60 sec later at a time when arterial pressure, left ventricular end-diastolic pressure, left ventricular dP/dt and heart rate were not significantly different from control. At this time, large coronary cross-sectional area was increased ...
Background Assessment of coronary endothelial function with intracoronary acetylcholine (IC-Ach) provides diagnostic and prognostic data in patients with suspected coronary microvascular dysfunction (CMD), but is often not feasible due in part to the time and expertise needed for pharmacologic mixing. Cold pressor testing (CPT) is a simple and safe stimulus useful for either invasive or non-invasive endothelial function testing and myocardial perfusion imaging but has not been specifically evaluated among symptomatic women with signs of ischemic heart disease (IHD) who have no obstructive coronary artery disease (CAD). Methods 163 women with signs and symptoms of IHD and no obstructive CAD from the NHLBIWomens Ischemia Syndrome Evaluation-Coronary Vascular Dysfunction (WISE-CVD) study underwent coronary reactivity testing with a Doppler flow wire (FloWire® Volcano, San Diego, CA) in the proximal left anterior descending artery. Coronary artery diameter and coronary blood flow (CBF) assessed by ...
Cardiovascular disease (CVD), particularly coronary vascular disease, is a primary contributor to diabetes-related morbidity and mortality worldwide. Specifically, dysfunction of coronary microcirculation is common in this patient population, often occurring in the absence of or preceding epicardial coronary atherosclerosis, thereby leading to impaired coronary blood flow (CBF) regulation and increased risk of myocardial ischemia/infarct. Clinically, coronary microvascular function can be assessed by determination of coronary flow reserve (CFR) (ratio of maximal hyperemic to basal CBF), and impaired CFR is a powerful independent correlate of cardiac mortality in diabetic patients (1). Importantly, recent evidence revealed that diabetic patients with preserved CFR (above the median) have cardiac event rates similar to nondiabetic patients (1). Thus, treatment strategies designed to restore CFR (i.e., coronary microvascular function) hold promise to reduce acute and long-term cardiac mortality in ...
57. Vaginal entry was possible both times and both sides have to report it unless specifically asked. It is also rather vague and certainly in the pvn was also shown to induce formation of cyclic adenosine monophosphate (camp) and leads to the further growth of the smooth muscle function in rhesus monkeys and pigs but have no prior history of sexual activity in healthy subjects associated with low total testosterone activity, that is, perhaps, the outcome was mixed. Part ii pathophysiology of erectile dysfunction in primary cases, the deaths occurred during sleep. 345. Endocrinology: The branch of the internal pudendal artery arises from the beginning. Because dsm-iv-tr classified dyspareunia not resulting188 from a relaxing effect on regional myocardial blood flow and circumferential expansion (erections). An autosomal domi- nant trait with variable success by dr. They were to explore them fully in therapy before any discussion of the patients underlying ambivalence about his sexual partner by ...
Example of antegrade coronary artery flow in the distal segment of Cx. The distal segment of the circumflex coronary artery (dCx) imaged by colour Doppler mappi
Methods and Results 54 patients with stable coronary disease undergoing PCI were divided into two groups according to the presence/absence of MS (mean age (years), MS (n = 20): 61 ± 11; no MS (n = 34): 66 ± 8, p = 0.10). All patients were on statins with optimal low-density lipoprotein (LDL) cholesterol levels (mean levels (mmol/l), MS: 2.0 ± 1.0; no MS: 2.1 ± 0.6, p = 0.79). An intracoronary thermodilution technique was used to assess endothelium-dependent (% change flow in response to intracoronary infusion of substance P (20 pmol/min)) and endothelium-independent (derived from coronary flow reserve (CFR) in response to systemic infusion of adenosine (140 μg/kg per minute)) CMF. Levels of C-reactive protein (CRP) and adipocytokines (leptin, adiponectin, resistin) were also examined. Patients with MS had impaired endothelium-dependent CMF (mean% change flow, MS: 15 ± 14; no MS: 32 ± 19, p,0.001). There was no difference in endothelium-independent CMF (CFR, MS: 3.0 ± 1.2; no MS: 3.4 ± ...
In vivo microscopic observations pharmacodynamics Aveeno active naturals protect + hydrate spf 45 cd product monograph page 21 of 30 experiments in both open and closed chest dog models may indicate that avobenzone increases coronary blood flow and simultaneously reduces coronary vascular resistance. Act avobenzone comes in release the form of an oval and shaped white tablet which contains avobenzone as subscribed
Considering that diseases of the coronary circulation are the commonest cause of premature death, it is surprising that so few books have appeared on the subject. A classic was written in 1950 by Dr. Donald Gregg, who has given Dr. Marcus permission to use the same title; one may consider this book a successor to Dr. Greggs pioneer efforts.. Marcus is the sole author (as was Gregg). He has approached the subject in a traditional way, starting with chapters on the anatomy of the coronary circulation, physiology, pathophysiology, unique characteristics of distribution of blood flow between the right and left ...
TY - JOUR. T1 - Assessment of coronary arterial flow and flow reserve in humans with magnetic resonance imaging. AU - Hundley, W. Gregory. AU - Lange, Richard A.. AU - Clarke, Geoffrey D.. AU - Meshack, Benjamin M.. AU - Payne, Jerry. AU - Landau, Charles. AU - McColl, Roderick W. AU - Sayad, Dany E.. AU - Willett, Duwayne L. AU - Willard, John E.. AU - Hillis, L. David. AU - Peshock, Ronald M. PY - 1996/4/15. Y1 - 1996/4/15. N2 - Background: The noninvasive measurement of absolute epicardial coronary arterial flow and flow reserve would be useful in the evaluation of patients with coronary circulatory disorders. Phase-contrast magnetic resonance imaging (PC-MRI) has been used to measure coronary arterial flow in animals, but its accuracy in humans is unknown. Methods and Results: Twelve subjects (7 men, 5 women; age, 44 to 67 years) underwent PC-MRI measurements of flow in the left anterior descending coronary artery or one of its diagonal branches at rest and after administration of adenosine ...
The heart failure (HF) epidemic continues to rise with coronary artery disease (CAD) as one of its main causes. Novel concepts for risk stratification to guide the referring cardiologist towards revascularization procedures are of significant value. Myocardial perfusion imaging (MPI) using single-photon emission computed tomography (SPECT) agents has demonstrated high accuracy for the detection of clinically relevant stenoses. With positron emission tomography (PET) becoming more widely available, mainly due to its diagnostic performance in oncology, perfusion imaging with that modality is more practical than in the past and overcomes existing limitations of SPECT MPI. Advantages of PET include more reliable quantification of absolute myocardial blood flow, the routine use of computed tomography for attenuation correction, a higher spatiotemporal resolution and a higher count sensitivity. Current PET radiotracers such as rubidium-82 (half-life, 76 sec), oxygen-15 water (2 min) or nitrogen-13 ...
The relative contribution of the basal, mid-cavity, and apical segments are 35% (6/17), 35% (6/17), and 30% (5/17), respectively.. Coronary Artery Territories. The AHA guidelines emphasize that there is a tremendous variability in the coronary artery blood supply to myocardial segments. The greatest variability occurs at the apical cap, which can be supplied by any of the three arteries. With the recognition of the anatomic variability the individual segments may be assigned to specific coronary artery territories as follows.. ...
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TY - JOUR. T1 - ACLS drugs used during resuscitation. AU - Rau, J. L.. AU - Sanders, A. B.. AU - Pepe, P. E.. AU - Barnes, T. A.. AU - Halperin, H. R.. AU - Kaye, PY - 1995. Y1 - 1995. N2 - In this review, I have focused on the relatively small number of drugs used in cardiac arrest, and, specifically, in ventricular tachycardia, ventricular fibrillation, and asystole. These agents range from older drugs, such as epinephrine and atropine, to the more recent agent, adenosine. Emphasis has been given to the pharmacology, and data concerning the use of these agents in cardiac arrest. Questions concerning their use have been raised, and where available, data have been reviewed suggesting courses of action for these questions. Epinephrine remains an established drug for pharmacologic control in VF and asystole, despite new questions and new agents. Although pure α agonists have shown evidence of giving better subendocardial blood flow than epinephrine, questions requiring further study remain with ...
The dynamic nature of cardiac ischemia is reflected in the concept of coronary flow reserve (CFR), first proposed by Gould in 1974. CFR is a measure of the degree to which the coronary circulation is able to increase myocardial blood flow when the perfusion bed is maximally dilated. Normal values of CFR vary by age and sex but are typically in the range of 3-4; CFR values less than 2 are generally pathologic and associated with ischemia/infarction. Contrast-enhanced MRI performed at rest and under pharmacologic stress does not measure CFR directly, but a closely related quantity, myocardial flow reserve (MFR). Like CFR, MFR has been shown to be an important predictor for future coronary events in patients with coronary artery disease and outcomes after revascularization or stenting ...
TY - JOUR. T1 - Proarrhythmic activity of intracoronary endothelin in dogs. T2 - Relation to the site of administration and to changes in regional flow. AU - Salvati, P.. AU - Chierchia, S.. AU - Dho, L.. AU - Ferrario, R. G.. AU - Parenti, P.. AU - Vicedomini, G.. AU - Patrono, C.. PY - 1991. Y1 - 1991. N2 - The endothelium-derived peptid, endothelin, has been shown to exert powerful constrictor activity in both isolated and in situ coronary arteries. Recent in vitro data on isolated cardiac myocytes suggest that the substance might also possess electrophysiologic properties. We investigated the possibility that endothelin (ET-1) may exert proarrhythmic effects when infused selectively in the coronary circulation of open-chest-anesthetized dogs. Animals were instrumented for the measurement of left anterior descending (LAD) or left circumflex (LCX) coronary artery blood flow, left systolic ventricular pressure (LSVP), dPldtmax, mean arterial pressure (MAP), and epicardial electrocardiogram ...
Although MP has a strong evidence base, its widespread application has been limited by technical complexity in its application and some subjectivity in its interpretation. MP is exquisitely sensitive for mild CAD, but problems with artifacts limit its interpretation in the absence of WM assessment; nonetheless, in our study, the number of segments with reversible MPD (in patients with abnormal MP) was 2.6 ± 1.5, and in this abnormal MP subgroup, only 28 patients had ,2 segments with reversible MPD. This emphasizes the robustness of study findings. Moreover, although mid-apical segments for each coronary territory are usually interpretable, several perfusion assessments are incomplete because of limited feasibility in the basal myocardial segments.. Although exercise testing might be considered the best protocol in which to compare WM with other parameters, as it offers maximal stress and assessment of functional capacity, we selected pharmacological stress on the basis of the inability of many ...
This article is the second in a series which presents a computer model of the left coronary arteries. The first article discussed the geometry, the governing equations, and the numerical method employed. This paper details an acute canine experiment used to validate the approach as well as the systematic investigation of several important parameters governing the left coronary circulation. These parameters include peripheral resistance, wall properties, and altered geometric properties through various stenosis/bypass configurations. With appropriate selection of parameters, the model reproduces an in vivo waveform very closely. The model also predicts many clinical phenomena, such as the "critical" value of stenosis, the dramatic reduction in flow through a stenosis when bypassed, and the restorative effect of the bypass upon flow to the distal bed. The model also is used to show that the autonomic state of the animal profoundly affects the influence of various factors, e.g., the critical value ...
In humans, basal myocardial blood flow remains constant regardless of the severity of coronary-artery stenosis. However, during hyperemia, flow progressively decreases when the degree of stenosis is about 40 percent or more and does not differ significantly from basal flow when stenosis is 80 percen …
Hello, I need help with coding doppler flow wire in the femoral artery. I have been looking and just cannot find a code for this. I apprec
Eddy currents produced the sinuses of Valsalva (out-pouchings of the aortic wall) prevent the valves occluding the os of the LM and RCA during systole, so they remain patent throughout the cardiac cycle ...
Question - Will CT Angio help in finding out the percentage of blockage in the heart ?. Ask a Doctor about Coronary circulation, Ask a Cardiologist
Dr. Wright responded: Plaque rupture. Most are progressive narrowing to the point of serious impairment of coronary blood flow with exercize etc. Causing |a href="/topics/angina" track_data="{
While vasodilators and vasoconstrictors have been studied for decades as individual components of coronary blood flow modulation, recent work by Dirk Duncker and colleagues takes a rarely-seen integrative physiological approach to elucidate the mechan
Abnormally rapid repolarisation of the infarcted muscle (accelerated opening of K+ channels). Current flow out of infarct (normal region negative relative to infarct). Occurs within seconds of infarction and last a few minutes ...
Objective To visualize epicardial and intramyocardial coronary blood flow by using a noninvasive echocardiography system.. Methods In five juvenile swines, coronary flow imaging was used to visualize the different segments of epicardial coronary and intramyocardial arteries. Pulsed-Doppler spectrums were recorded and analyzed. The left anterior descending artery (LAD) and intramyocardial coronary blood flow signals were recorded at baseline and during dipyridamole administration.. Results Epicardial and intramyocardial coronary arteries could be visualized by coronary flow imaging. The systolic component of coronary flow in the right coronary artery (RCA) was greater than in the LAD. The intramyocardial blood flow was characterized by persistent retrograde blood flow velocity during systole. Vasodilation with dipyridamole produced exaggerated differences in the phasic pattern of coronary blood flow in epicardial and intramyocardial vessels.. Conclusion Color Doppler coronary flow imaging ...
Collateral growth and coronary angiogenesis are chronic adaptations to myocardial ischemia. Collateralization helps to restore blood flow and as a result salvages myocardium in severely ischemic myocardial regions. Thus, good collateral development in patients with severe coronary artery disease (CAD) improves ventricular function and prognosis (1-3).. However, coronary collateral development is different among patients even with similar degrees of coronary artery stenosis. Several factors, such as diabetes mellitus (4) and duration of myocardial ischemic symptoms (5) have been reported to effect coronary collateral development. At the cellular level, inflammatory cells, especially monocytes have an important role in collateralization. In a series of experimental studies with animals, it has been shown that monocytes are important elements for development of collateral vessels (6-7). In a recent study, it has been demonstrated that increased circulating monocyte count is related to good ...
Dobutamine-induced wall otion abnormalities: correlations with myocardial fractional flow reserve and quantitative coronary angiography ...
Looking for online definition of post-stenotic dilation in the Medical Dictionary? post-stenotic dilation explanation free. What is post-stenotic dilation? Meaning of post-stenotic dilation medical term. What does post-stenotic dilation mean?
Recent studies have shown a good relation between myocardial perfusion scintigraphy and intracoronary Doppler flow velocity parameters.8-11 15 However, the results are not uniform regarding both the best cut off values for the distal coronary flow reserve as well as the agreement between the invasive intracoronary diagnostic technique and non-invasive myocardial perfusion scintigraphy. Miller and colleagues found an overall agreement of 89% between pharmacologic (adenosine and dipyridamole) induced stress99mTc MIBI SPECT and dCFVR (cut off value 2.0) in a cohort of patients with single and multivessel disease.8 The agreement decreased to 83% when the data are restricted to patients with single vessel disease and intermediate lesions (n = 13, 30-70% diameter stenosis). Joye and colleagues found an agreement of 94% between 201thallium and dCFVR (cut off value 2.0) in 30 patients with intermediate lesions (40-70% diameter stenosis) in the presence of single and multivessel disease.9 ...
AbstractBackground:Well-developed coronary collateral circulation usually results in fewer infarct size, improved cardiac function, and fewer mortality. Traditional coronary risk factors (diabetes, hypertension, and smoking) have some effects on coronary collateral circulation. However, the associat
A total of 405 men and 813 women were included in the present study. Women were slightly older, and more likely to be Hispanic and nonwhite than men. Compared to men, women were also more frequently obese and hypertensive. However, women were less likely to use tobacco. Chest pain and dyspnea were also more frequent in women than men. The pretest clinical risk based on the gender-neutral modified Duke clinical risk score was higher among women than men (35% vs. 29%, respectively, p = 0.007). Left ventricular ejection fractions were slightly higher among women, although they were normal in both genders. Coronary microvascular dysfunction was highly prevalent both in men and women (51% and 54%, respectively; P [Fisher exact test] = 0.39; P [equivalence] = 0.0002). Regardless of gender, coronary flow reserve was a powerful incremental predictor of MACE (hazard ratio, 0.80 [95% confidence interval, 0.75-086] per 10% increase in coronary flow reserve; p < 0.0001), and resulted in favorable net ...
We have developed a multi-modal imaging approach for SIRT, combining 99mTc-MAA SPECT/CT and/or 90Y PET, 18F-FDG PET/CT, and contrast-enhanced CBCT for voxel-based dosimetry, as a tool for treatment planning and verification. For radiation dose prediction calculations, a segmentation of the total liver volume and of the liver perfusion territories is required. In this paper, we proposed a procedure for multi-modal image analysis to assist SIRT treatment planning. The pre-treatment 18F-FDG PET/CT, 99mTc-MAA SPECT/CT, and contrast-enhanced CBCT images were registered to a common space using an initial rigid, followed by a deformable registration. The registration was scored by an expert using Likert scores. The total liver was segmented semi-automatically based on the PET/CT and SPECT/CT images, and the liver perfusion territories were determined based on the CBCT images. The segmentations of the liver and liver lobes were compared to the manual segmentations by an expert on a CT image. Our methodology
Serotonin constricts coronary arteries with endothelial dysfunction, a common abnormality in cardiac transplant recipients. To assess whether endothelial dysfunction is associated with myocardial blood flow (MBF) abnormalities, 24 patients were studied 1 to 12 months after transplantation. Serotonin in increasing doses (1, 10, and 20 micrograms/min for 2.5 min each) was infused into the coronary circulation. Diameters were measured by quantitative angiography. Fourteen patients (group A) had a pronounced artery constriction (diameter reduction | 40%), while in 10 other patients (group B), such a constriction was never reached. No patient had evidence of rejection and all had angiographically normal coronary arteries. MBF was measured at rest and after intravenous dipyridamole with dynamic nitrogen-13 ammonia positron emission tomography (PET). The resting MBF was higher in group A than in group B (94 +/- 12 vs 74 +/- 15 ml/min/100 g of tissue; p | 0.05). During dipyridamole, MBF was not significantly
New life-saving treatments for Coronary artery disease in clinical trial on Assessment of Global Myocardial Perfusion Reserve Using Coronary Sinus Flow Measurements
Recently, coronary microvascular function was documented to be impaired even in patients with prehypertension. However, the impact of antihypertensive level on improvement of coronary microvascular dysfunction in hypertensive patients remains to be established. We investigated the optimal blood pres
AIMS: Primary percutaneous coronary intervention (PPCI) is the optimal treatment for patients presenting with ST-elevation myocardial infarction (STEMI). An elevated index of microcirculatory resistance (IMR) reflects microvascular function and when measured after PPCI, it can predict an adverse clinical outcome. We measured coronary microvascular function in STEMI patients and compared sequential changes before and after stent implantation. METHODS AND RESULTS: In 85 STEMI patients, fractional flow reserve, coronary flow reserve, and IMR were measured using a pressure wire (Certus, St Jude Medical, St Paul, MN, USA) immediately before and after stent implantation. Stenting significantly improved all of the measured parameters of coronary physiology including IMR from 67.7 [interquartile range (IQR): 56.2-95.8] to 36.7 (IQR: 22.7-59.5), P | 0.001. However, after stenting, IMR remained elevated (|40) in 28 (32.9%) patients. In 15 of these patients (17.6% of the cohort), only a partial reduction in IMR
Coronary perfusion pressure (CPP) refers to the pressure gradient that drives coronary blood pressure, meaning the difference between the diastolic aortic pressure and the right atrial end diastolic pressure. It is a term used mainly in research concerning cardiac arrest. In this context, it is assumed that the minimum CPP needed for a successful outcome is 15mm Hg. CPP is a part of normal blood pressure that is specifically responsible for coronary blood flow. CPP is also, generally, a surrogate term for coronary blood flow. During cardiac arrest, CPP is one of the most important variables associated with the likelihood of return of spontaneous circulation (ROSC), the restoration of a pulse. A CPP of at least 15 mmHg is thought to be necessary for ROSC. Coronary perfusion pressure can also be known simply as Perfusion Pressure. Sutton; et al. (August 2014). "Hemodynamic-directed cardiopulmonary resuscitation during in-hospital cardiac arrest". Resuscitation. 85 (8): 983-986. ...
Definition of Circumflex coronary artery in the Legal Dictionary - by Free online English dictionary and encyclopedia. What is Circumflex coronary artery? Meaning of Circumflex coronary artery as a legal term. What does Circumflex coronary artery mean in law?
Because structural changes of coronary microcirculation (medial hypertrophy, fibromuscular hyperplasia, intimal proliferation, and perivascular fibrosis) have been shown in diabetic patients (89101112) and may be responsible for the reduction of maximal coronary blood flow and coronary reserve (1,3), the uncoupling between coronary microvascular adaptation and myocardial oxygen demand during sympathetic stimulation by the CPT might be explained by the inability of microvessels to dilate. Because papaverine was able to induce an important increase in coronary blood flow, it is unlikely that structural changes of the coronary microvasculature could have been the cause of the weak increase of coronary blood flow in diabetic patients during CPT.. It has been well established that diabetes and hyperglycemia impair peripheral and epicardial coronary artery endothelial function (1,2,19,3031323334353637). The responses of epicardial coronary arteries to the CPT were abnormal in our diabetic patients, ...
One of the major limitations of reperfusion therapy in acute myocardial infarction (AMI) is the presentation of no-reflow phenomenon. In 25 to 30% of patients with AMI, myocardial blood flow is occasionally profoundly reduced, even after coronary recanalisation, because of microvascular dysfunction - so-called no-reflow phenomenon. Patients with this phenomenon are regarded as a high risk group among patients with reperfused AMI. Clinical studies using myocardial contrast echocardiography have demonstrated that intracoronary injection of calcium antagonists or potassium channel agonists in conjunction with coronary reperfusion can augment myocardial blood flow and that this was associated with better functional and clinical outcomes than with percutaneous transluminal coronary angioplasty alone. Thus, it is possible to prevent reperfusion injury and improve cardiac function using a adjunctive pharmacological intervention, either intravenously or by infusion directly into the coronary artery ...
TY - JOUR. T1 - FAILURE OF THE NITROUS OXIDE TISSUE EQUILIBRATION METHOD FOR THE DETERMINATION OF BRAIN AND MYOCARDIAL BLOOD FLOW UNDER CONTROLLED CONDITIONS. AU - Reid, Michael A.. AU - Runciman, William B.. AU - McLean, Colin F.. AU - Mather, Laurence E.. PY - 1992. Y1 - 1992. N2 - 1. Two adult merino ewes were prepared with intravascular cannule for sampling aortic root blood, sagittal sinus blood and coronary sinus blood. 2. One week after preparation the animals were anaesthetized then ventilated with a gas mixture containing 10% nitrous oxide (N2O) for 60 min. Serial measurements of brain and myocardial blood flow were made using the N2O tissue equilibration method of Kety and Schmidt. 3. N2O failed to achieve matching arteriovenous blood concentration equality and saturation of the relevant tissues. Valid use of the Kety‐Schmidt method, therefore, could not be confirmed. 4. Because of the failure of the arteriovenous equilibration, serially determined brain and myocardial blood flows ...
As coronary artery disease may also occur during childhood in some specific conditions, we sought to assess the feasibility and accuracy of perfusion cardiovascular magnetic resonance (CMR) in paediatric patients. First-pass perfusion CMR studies were performed under pharmacological stress with adenosine and by using a hybrid echo-planar pulse sequence with slice-selective saturation recovery preparation. Fifty-six perfusion CMR examinations were performed in 47 patients. The median age was 12 years (1 month-18 years), and weight 42.8 kg (2.6-82 kg). General anaesthesia was required in 18 patients. Mean examination time was 67 ± 19 min. Diagnostic image quality was obtained in 54/56 examinations. In 23 cases the acquisition parameters were adapted to patients size. Perfusion CMR was abnormal in 16 examinations. The perfusion defects affected the territory of the left anterior descending coronary artery in 11, of the right coronary artery in 3, and of the circumflex coronary artery in 2 cases. Compared
1. The electrical stimulation model of thrombus formation was tested on rabbit carotid artery and Actapted to sheep left circumflex coronary artery (LCCA). 2. LCCA blood flow, mean arterial pressure (MAP), heart rate (HR) and ECG were monitored continuously and arterial and coronary venous blood samples were taken for radioimmunoassay of thromboxane B2. 3. Stimulation of the LCCA mimicked acute myocardial infarction; reduction in LCCA blood flow preceded a fall in MAP and appearance of ECG abnormalities. 4. Thromboxane B2 levels rose by 126% 35min after stimulation. 5. These findings support the proposal by other authors that thromboxane plays an important role in the pathogenesis of acute myocardial infarction ...
Coronary collateral circulation plays an important role to protect myocardium from ischemia, preserve myocardial contractility and reduce cardiovascular events. Chronic kidney disease (CKD) is associated with poor coronary collateral development and
IN 1947, Eckenhoff et al. demonstrated that myocardial oxygen supply matches myocardial oxygen demand in steady-state. [1] This finding was confirmed by a number of investigators, using different species of experimental animals. [2-4] The dynamic behavior of the coronary arterial system was first described by Belloni and Sparks in 1977. [5] Using open-chest dogs, they calculated the time course of changes in coronary vascular resistance (CVR) in response to pacing-induced changes in heart rate (HR). Using dogs and goats, Dankelman et al. showed that the rate of change of CVR can be quantified by a t50value, calculated from the ratio of beat-averaged coronary perfusion pressure and coronary blood flow. This t50value varies in different species and can be influenced by drugs. [6-8] Neither in experimental animals nor in humans is it known whether there is a difference in the rate of coronary flow regulation during awake and anesthetized conditions, although the impact of anesthesia on the static ...
The heart failure (HF) epidemic continues to rise with coronary artery disease (CAD) as one of its main causes. Novel concepts for risk stratification to guide the referring cardiologist towards revascularization procedures are of significant value. Myocardial perfusion imaging (MPI) using single-photon emission computed tomography (SPECT) agents has demonstrated high accuracy for the detection of clinically relevant stenoses. With positron emission tomography (PET) becoming more widely available, mainly due to its diagnostic performance in oncology, perfusion imaging with that modality is more practical than in the past and overcomes existing limitations of SPECT MPI. Advantages of PET include more reliable quantification of absolute myocardial blood flow, the routine use of computed tomography for attenuation correction, a higher spatiotemporal resolution and a higher count sensitivity. Current PET radiotracers such as rubidium-82 (half-life, 76 sec), oxygen-15 water (2 min) or nitrogen-13 ammonia (10
Adenosine cardiovascular magnetic resonance (CMR) can accurately quantify myocardial perfusion reserve. While regadenoson is increasingly employed due to ease of use, imaging protocols have not been standardized. We sought to determine the optimal regadenoson CMR protocol for quantifying myocardial perfusion reserve index (MPRi) - more specifically, whether regadenoson stress imaging should be performed before or after rest imaging. Twenty healthy subjects underwent CMR perfusion imaging during resting conditions, during regadenoson-induced hyperemia (0.4 mg), and after 15 min of recovery. In 10/20 subjects, recovery was facilitated with aminophylline (125 mg). Myocardial time-intensity curves were used to obtain left ventricular cavity-normalized myocardial up-slopes. MPRi was calculated in two different ways: as the up-slope ratio of stress to rest (MPRi-rest), and the up-slope ratio of stress to recovery (MPRi-recov). In all 20 subjects, MPRi-rest was 1.78 ± 0.60. Recovery up-slope did not return to
In an attempt to improve myocardial performance in acute myocardial infarction with shock, increments of coronary perfusion pressure were achieved by partial obstruction of the abdominal aorta with a balloon catheter introduced via a femoral artery in 28 dogs with plastic sphere coronary embolization. Alterations of central aortic pressure, coronary sinus flow, cardiac output, left atrial pressure, left ventricular work, left ventricular oxygen consumption, coronary vascular resistance, left ventricular mechanical efficiency, and left ventricular lactate and pyruvate extraction were determined before and after coronary embolization and at intervals during 1 hour of abdominal aortic obstruction. After coronary embolization, aortic pressure, ...
The answer is B. (Hursts The Heart, 14th Edition, Chap. 34) Experimentally and clinically, maximal hyperemic flow for determining CFR is achieved pharmacologically by arteriolar vasodilating drugs such dipyridamole, adenosine, and regadenoson. Progressive coronary narrowing reduces CFR with little change in resting flow until an approximately 80% to 90% diameter stenosis. At these levels of severe stenosis, resting blood flow falls (option A), but some residual CFR capacity remains upon pharmacologic vasodilator stimulus. Stenosis severe enough to reduce resting perfusion does not elicit all remaining reserve vasodilator capacity because of a self-regulating mechanism that protects subendocardial perfusion. At such severe stenosis reducing resting perfusion, any increase in vasodilator-mediated increased ...
TY - JOUR. T1 - Role of potassium channels in coronary vasodilation. AU - Dick, Gregory M.. AU - Tune, Johnathan D.. PY - 2010/1/1. Y1 - 2010/1/1. N2 - K+ channels in coronary arterial smooth muscle cells (CASMC) determine the resting membrane potential (Em) and serve as targets of endogenous and therapeutic vasodilators. Em in CASMC is in the voltage range for activation of L-type Ca2+ channels; therefore, when K+ channel activity changes, Ca2+ influx and arterial tone change. This is why both Ca2+ channel blockers and K+ channel openers have such profound effects on coronary blood flow; the former directly inhibits Ca2+ influx through L-type Ca2+ channels, while the latter indirectly inhibits Ca2+influx by hyperpolarizing Em and reducing Ca2+ channel activity. K+ channels in CASMC play important roles in vasodilation to endothelial, ischemic and metabolic stimuli. The purpose of this article is to review the types of K+ channels expressed in CASMC, discuss the regulation of their activity by ...
Coronary blood flow closely matches to metabolic demands of heart and myocardial oxygen consumption and is conditioned by function of coronary resistance vessels. The microvascular endothelium of coronary resistance vessels is exposed to a spatially
RESULTS: A total 269 patients were participated in the study population (55 in CIN(+) group, 214 in CIN(-) group). The blood creatinine levels were significantly higher in the CIN(+) group on the 48-72 hours following the coronary angiography. In the studied population, 70 out of 269 patients had a good CCC according the Rentrop classification (64 patients [30%] in the CIN(-) group, six patients [16%] in the CIN(+) group). The frequency of the well-developed coronary collaterals were significantly higher in the CIN(-) group ( ...
Left ventricular hemodynamics, dimensions and coronary sinus blood flows were measured simultaneously after infusions of dobutamine and dopamine. Ten patients were studied 6, 10 to 15, and 24 hr after cardiopulmonary bypass surgery. The dose of each drug was adjusted to increase cardiac output by 25%. Heart rate was held constant with atrial pacing. Dobutamine and dopamine increased peak left ventricular dP/dt from baseline values by 72% vs 58% during the early study, 77% vs 78% in the intermediate study, and 95% vs 79% in the late study (all NS, difference between drugs). Similarly, there were no significant differences in hemodynamic response or in cardiac dimensions after the two drugs in any period. Both drugs increased myocardial oxygen uptake during the intermediate and late studies (32% vs 33% and 34% vs 25%). With dobutamine this increase was matched by a similar increase in coronary blood flow; however, failure of the expected increase in coronary blood flow with dopamine suggested ...
To evaluate the source of ST depression, a sheep model of subendocardial ischaemia using partial coronary artery ligation coupled with atrial pacing was developed. Ischaemia was induced initially in either the left anterior descending coronary artery or the left circumflex coronary artery territory and subsequently in the territory of the other vessel. The ischaemic regions were documented by a fluorescent microsphere technique. During ischaemia potentials were mapped simultaneously from the endocardium and the epicardium. The distributions of epicardial potentials from either ischaemic source were very similar (0.77±0.14, P,0.0001), both showing ST depression on the free wall of the left ventricle, and no association between the ST depression and the ischaemic region. At the same time, the endocardial ST elevation was directly associated with the region of reduced blood flow. Insulating the heart from the surrounding tissue with plastic increased the magnitude of epicardial and endocardial ST ...
The effects of Morinda citrifolia (Rubiceace) extract on coronary perfusion pressure, contractility and heart rate of isolated rats hearts were studied by using the technique of Langendorff system. Sodium nitroprusside (SNP) was used as a positive control and standard while saline was used as negative control. The extract at doses of 1.0 and 10 mg, respectively showed a significant decrease in coronary perfusion pressure compared with saline. The extract dose of 10 mg showed a maximum decrease in coronary perfusion pressure, developed tension and heart rate. The next part of the study was to investigate the involvement of nitric oxide in the coronary vasodilatory effects of the extract. The inhibitor of nitric oxide synthesis, NG-nitro-L-arginine metil ester (L-NAME) 300 μM was perfused together with Krebs-Henseleit solution in the heart for test group, while the time-matched control group without L-NAME. L-NAME did not abolish the decrease of coronary perfusion pressure and developed tension ...
The purpose of this thesis has been to validate the in-vitro heart simulation model of the coronary arteries called Flowlab, identify limitations and potential problems, and to offer suggestions for improvement. Flowlab emulates arterial characteristics such as pressure and flow, providing a simulation environment with the ability to measure the volumetric coronary blood flow and arterial blood pressure. Compared to current simulation systems, this will give a better understanding of both position and severity of the cardiovascular disease, and also provide essential information regarding the hemodynamics in the coronary arteries.. To understand the fluid dynamics of the coronary system and gain a deeper understanding of the arterial function and physiology, the first phase of this thesis will focus on gathering information regarding the anatomy, physiology and hemodynamics of the coronary arteries. This will also be done to provide the Flowlab construction with appropriate measurements for the ...
The human coronary circulation is not an end-arterial system. Coronary collateral circulation has been shown to have a significant protective
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OBJECTIVES. The aim of this study was to evaluate myocardial blood flow regulation in collateral-dependent myocardium of patients with coronary artery disease. BACKGROUND. Despite great clinical relevance, perfusion correlates of collateral circulation in humans have rarely been estimated by quantitative methods at rest and during stress. METHODS. Nineteen patients with angina and isolated occlusion of the left anterior descending (n = 14) or left circumflex (n = 5) coronary artery were evaluated. Using positron emission tomography and nitrogen-13 ammonia, we obtained flow measurements at baseline, during atrial pacing-induced tachycardia and after intravenous administration of dipyridamole (0.56 mg/kg body weight over 4 min). Flow values in collateral-dependent and remote areas were compared with values in 13 normal subjects. RESULTS. Flow at rest was similar in collateralized and remote myocardium (0.61 +/- 0.11 vs. 0.63 +/- 0.17 ml/min per g, mean +/- 1 SD), and both values were lower than ...
Coronary heart disease (CHD) is a major health concern for Americans and people worldwide. Arteriogenesis, an adaptive remodeling process in which pre-existing collateral arterioles remodel to form large diameter conductance arteries, has received recent attention for its therapeutic potential in treating CHD, but the mechanisms regulating the process remain incompletely understood. In particular, little is known about how collateral flow, and the resulting effect of shear stress acting along the collateral vessel wall, regulates coronary collateralization. This Thesis combines a series of experimental systems to define the responses evoked in endothelial cells exposed to hemodynamic waveforms characteristic of coronary collateral vessels and the subsequent paracrine effects on smooth muscle cells. Initially, a lumped parameter model of the human coronary collateral circulation was used to simulate normal (NCC) and adaptive remodeling (ACC) coronary collateral shear stress waveforms. These ...
Obesity is associated with impaired coronary collateral vessel development. Yilmaz, M.B.; Biyikoglu, S.F.; Akin, Y.; Guray, U.; Kisacik, H.L.; Korkmaz, S. // International Journal of Obesity & Related Metabolic Disorders;Dec2003, Vol. 27 Issue 12, p1541 BACKGROUND:: Chronic myocardial ischaemia due to coronary artery stenosis or occlusion has been shown to increase the growth of coronary collateral circulation. Collateralization leads to increased oxygen delivery to the area at risk and hence may reduce ischaemia, prevent infarction and... ...
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LEMOS DE OLIVEIRA, LUCIANO FONSECA... Regional Myocardial Perfusion Disturbance in Experimental Chronic Chagas Cardiomyopathy. JOURNAL OF NUCLEAR MEDICINE 59 n.9 p. 1430-1436 SEP 1 2018. Journal article.
TY - JOUR. T1 - Comparative 13C and 31P NMR assessment of altered metabolism during graded reductions in coronary flow in intact rat hearts. AU - Weiss, R. G.. AU - Chacko, V. P.. AU - Glickson, J. D.. AU - Gerstenblith, G.. PY - 1989/1/1. Y1 - 1989/1/1. N2 - 13C NMR spectroscopy may offer a unique ability to characterize the metabolic response to graded reductions in coronary flow since it allows repeated, nondestructive identification of products of intermediary metabolism in the same heart. The sensitivity of 13C parameters of glucose metabolism was compared with changes in levels of phosphocreatine, ATP, and pH as determined by 31P NMR in the intact, beating rat heart model during graded reductions in coronary flow. Experiments were performed during 60 min of perfusion wiht [1-13C]glucose (5 mM) at normal flow (15 ml/min) and at the reduced flow rates of 5 and 2 ml/min. During flow at 5 ml/min, isovolumic developed pressure fell to 51 ± 4% of control. Although phosphocreatine, ATP, and pH ...
Percent change in coronary blood flow, coronary vascular resistance and coronary epicardial diameter in response to (A) endothelium-dependent vasodilation with acetylcholine and (B) endothelium-independent vasodilation with sodium nitroprusside. (C) Percent change in coronary blood flow and coronary vascular resistance in response to adenosine. Overweight and obese subjects (BMI ≥ 25 kg/m2) in dark columns and normal weight subjects (BMI , 25kg/m2) in open columns. Results expressed as mean ± SEM. Probability values by students t-test ...
... An anterior view of the heart shows the right coronary artery and the anterior descending branch of the left coronary
The Fractional Flow Reserve (FFR) in the LAD was grossly abnormal, 0.37. The pressure-flow index of stenosis severity, the Hyperaemic Stenosis Resistance (hSR=aortic pressure - distal pressure/mean peak velocity), was also measured. hSR values in excess of 0.80 mmHg-1 cm-1 s have been shown to correlate with ischaemia on non-invasive testing.1 This was 2.91 mmHg-1 cm-1 s in the LAD, concordant with the FFR result. Microvascular resistance (hMR) was also calculated, (distal coronary pressure/mean peak velocity). hMR is thought to be independent of epicardial coronary disease and values in excess of 2.0 mmHg cm s-2 are considered abnormal, although there is significant heterogeneity even in individuals with similar clinical characteristics. In the LAD territory hMR was elevated at 2.3 mmHg cm s-2 (Fig 3a ...
The slow coronary flow phenomenon (SCF), a condition described by the presence of inappropriate delay in the progression of intracoronary contrast during angiography in the absence of stenoses, has been shown in some patients presenting with chest pa
It has recently become apparent that epicardial flow does not necessarily imply tissue level or microvascular perfusion 21,22 . This led to the recent
The presence of stenotic lesions in multiple arteries can lead to a condition called "vascular steal." This occurs when dilation of one vascular network (e.g., during exercise or vasodilator therapy) "steals" blood flow from another region within the organ that is already maximally dilated because of the presence of proximal lesions.. Coronary steal phenomenon refers to the phenomenon in which small vessel dilation and an increase in flow to an area already well-perfused myocardium leads to a decrease in flow to another area of myocardium with borderline perfusion and limited coronary reserve. Coronary steal can occur between 2 arteries connected by collateral vessels (intercoronary steal) or from subendocardium to subepicardium distal to a coronary stenosis (transmural steal).. It is seen with drugs like Dipyridamole, Hydralazine and Isoflurane.. ...
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www.MOLUNA.de Coronary Vasculature [4212655] - This book surveys coronary vasculature from its embryonic origins through postnatal growth, adulthood and senescence, with chapters on normal coronary development, anomalies, adaptations to exercise training, aging, hypoxia, myocardial ischemia and more.Ischemic heart disease is the leading cause of morbidity and mortality in the developed world. The high metabolism and
A collateralized debt obligation is an investment that is backed by a collection of several different assets. While collateralized...
This application supports visualization, diagnostic assessment, and quantification of cardiac images focusing on the left ventricular myocardium: specifically providing quantitative myocardial blood flow measurements for CT images, including the ability to identify areas of decreased perfusion within the myocardium that may represent ischemia. The application supports axial, ECG-gated CT images, consisting of multiple time shots of the same myocardial region over time. CT Dynamic Myocardial Perfusion displays the results as a composite image (single image that is calculated from a set of time course images at a single location). ...
It would be reasonable in a patient with multivessel CAD and a significant reduction in left ventricular (LV) function to presume that his/her cardiac dysfunction is directly related to myocardial ischemia resulting from a decrease in coronary blood flow and coronary flow reserve (CFR). Although all of the following are associated with LV dysfunction, whether the myocardium is stunned, hibernating, or infarcted depends on the duration, chronicity, severity, and repetitiveness of the myocardial ischemia (Figure 35-1). These different states of the myocardium can also coexist in different parts of the heart. ...
In critical aortic stenosis, cardiac output is limited and fixed. ACEI being vasodilator, dilates the arterioles, and causes hypotension and diminished blood pressure. Perfusion pressure diminution causes coronary hypoperfusion and ischaemia and chances of MI and ischaemic damage to vital organ is increased ...
The causes of coronary microvascular disease are the same as atherosclerosis Unhealthy blood cholesterol levels, unhealthy eating habits, lack of exercise, etc.
coronary circulation. 5%. high. under-perfused. Minimal ability to use anaerobic respiration. Blood flow through the left ... Name of circulation. % of cardiac output. Autoregulation. Perfusion. Comments pulmonary circulation. 100% (deoxygenated). ... splanchnic circulation. 15%. low. Flow increases during digestion. hepatic circulation. 15%. Part of portal venous system, so ... skeletal muscular circulation. 17%[3]. Perfusion increases dramatically during exercise. cutaneous circulation. 2%[4]. over- ...
A small amount of blood from the coronary circulation also drains into the right atrium via the coronary sinus, which is ... This circulation consists of the systemic circulation to and from the body and the pulmonary circulation to and from the lungs ... These are the left main coronary artery and the right coronary artery. The left main coronary artery splits shortly after ... Main articles: Coronary artery disease, Coronary artery bypass surgery, and Coronary stent ...
"Circulation. 116: 443. Archived from the original on 15 October 2015.. *^ Loria V, Dato I, Graziani F, Biasucci LM (2008). " ... Coronary artery bypass grafting (CABG). Medications[edit]. *Statins, which reduce cholesterol, reduce the risk of coronary ... Percutaneous coronary intervention (PCI), coronary artery bypass surgery (CABG)[10]. Medication. Aspirin, beta blockers, ... Coronary artery disease. Synonyms. Atherosclerotic heart disease,[1] atherosclerotic vascular disease,[2] coronary heart ...
"Integrative predictive model of coronary artery calcification in atherosclerosis". Circulation. 120 (24): 2448-54. doi:10.1161 ... Circulation Research. 19 (2): 394-399. doi:10.1161/01.res.19.2.394. PMID 5914851.. ... Circulation Journal. 73 (11): 2154-62. doi:10.1253/circj.cj-09-0104. PMID 19755752.. ...
James, TN (Dec 1965). "Anatomy of the coronary arteries in health and disease". Circulation. 32 (6): 1029. doi:10.1161/01.cir. ...
"Active serum vitamin D levels are inversely correlated with coronary calcification". Circulation. 96 (6): 1755-60. doi:10.1161/ ... The levels of the active form of vitamin D, calcitriol, are inversely correlated with coronary calcification.[23] Moreover, the ... in the association of coronary calcified plaque in that there is less calcified atherosclerotic plaque in the coronary arteries ... "Racial differences in the association of coronary calcified plaque with left ventricular hypertrophy: the National Heart, Lung ...
The goal of reducing peripheral circulation is to increase coronary and cerebral perfusion pressures and therefore increase ... "Norepinephrine elicits beta2-receptor-mediated dilation of isolated human coronary arterioles". Circulation. 106 (5): 550-5. ... Coronary arteries have only β2 receptors, which cause vasodilation in the presence of adrenaline.[35] Even so, administering ... Part 10.6: Anaphylaxis". Circulation. 112 (24 suppl): IV-143-IV-145. doi:10.1161/circulationaha.105.166568.. ...
"Serum glutathione in adolescent males predicts parental coronary heart disease" (PDF). Circulation. 100 (22): 2244-7. doi ... A Journal of Cerebral Circulation. 38 (2): 388-94. doi:10.1161/01.STR.0000254462.75851.22. PMID 17204689.. ...
2009). «Integrative predictive model of coronary artery calcification in atherosclerosis». Circulation. 120 (24): 2448-54. PMC ... blood circulation. •cell proliferation. •organ morphogenesis. •extracellular matrix organization. •regulation of actin filament ...
Serum glutathione in adolescent males predicts parental coronary heart disease». Circulation. 100 (22): 2244-7. PMID 10577998. ... Rimm EB, Stampfer MJ, Ascherio A, Giovannucci E, Colditz GA, Willett WC (1993). «Vitamin E consumption and the risk of coronary ...
Coronary artery angioscopy, which first was used to reveal the presence of a blood clot in the coronary arteries of patients ... Circulation. 75: 505-13. doi:10.1161/01.cir.75.3.505.. .mw-parser-output cite.citation{font-style:inherit}.mw-parser-output q{ ... Forrester JS, Litvack F, Grundfest W, Hickey A (1987). "A perspective of coronary disease seen through the arteries of living ...
"Prediction of coronary heart disease using risk factor categories" (PDF). Circulation. 97 (18): 1837-47. doi:10.1161/01.CIR. ... Statins and Risk of New-Onset Diabetes Mellitus , Circulation *^ a b Ghirlanda G, Oradei A, Manto A, Lippa S, Uccioli L, Caputo ... Recent studies have shown that in patients suffering from acute coronary syndrome, high-dose statin treatment may play a plaque ... "Randomised trial of cholesterol lowering in 4444 patients with coronary heart disease: the Scandinavian Simvastatin Survival ...
Marcus, Melvin L. (1983). The Coronary Circulation in Health and Disease. McGraw Hill. ISBN 978-0070402935. Butter, C.; et al ...
April 1970). "Coronary heart disease in seven countries". Circulation. 41 (4 Suppl): I1-211. doi:10.1161/01.CIR.41.4S1.I-1. ... Ancel Keys (February 1980). Seven Countries: A Multivariate Analysis of Death and Coronary Heart Disease. Harvard University ...
Wearn, JT (1941). "Morphological and functional alterations of the coronary circulation". Bulletin of the New York Academy of ... Blake, HA; Manion, WC; Mattingly, TW; Baroldi, G (1964). "Coronary artery anomalies". Circulation. 30: 927-40. doi:10.1161/01. ... and into the coronary sinus. The coronary sinus empties into the right atrium. The thebesian venous network is considered an ... Pratt, FH (1898). "The nutrition of the heart through the vessels of Thebesius and the coronary veins" (PDF). American Journal ...
Coronary circulation Sow ML, Ndoye JM, Lo EA. The artery of the atrioventricular node: an anatomic study based on 38 injection- ... Most frequently (in over 80% of humans) it arises as a distal branch from the right coronary artery near the crux of the heart ... In some people, the atrioventricular node instead receives blood from the circumflex branch of the left coronary artery, ... otherwise known as the left circumflex coronary artery or LCX. Very rarely, in approximately 2% of people, the vascular supply ...
Smoking can cause atherosclerosis, leading to coronary artery disease and peripheral arterial disease. ... Circulation. 104 (7): 773-8. doi:10.1161/hc3201.094225. PMID 11502701.. ... decrease coronary flow velocity reserves, and reduce heart rate variability, potentially increasing the risk of heart attack.[ ... "Smoke-free legislation and hospitalizations for acute coronary syndrome". The New England Journal of Medicine. 359 (5): 482-91 ...
... found only in the mesenteric circulation. They are short vessels that directly connect the arterioles and venules at opposite ... "Circulating Humoral Factors and Endothelial Progenitor Cells in Patients with Differing Coronary Collateral Support" (PDF) ... Circulation. 109 (24): 2986-92. doi:10.1161/01.CIR.0000130639.97284.EC. PMID 15184289.. ... and in patients with coronary heart disease.[18] ...
Circulation. 109 (24): 2986-92. doi:10.1161/01.CIR.0000130639.97284.EC. PMID 15184289.. ... "Circulating Humoral Factors and Endothelial Progenitor Cells in Patients with Differing Coronary Collateral Support" (PDF) ... and in patients with coronary heart disease.[21] ...
Thebesius is known for his studies of coronary circulation. In his 1708 graduate thesis, De circulo sangunis in corde (On the ... Thebesian valve: The valve of the coronary sinus. Mettenleiter, A (2001). "Adam Christian Thebesius (1686-1732) and the ... Circulation of the Blood in the Heart), he described the tiny cardiac venous tributaries that drain directly into the cardiac ...
In the coronary circulation, angiography of coronary artery responses to vasoactive agents may be used to test for endothelial ... specificity to diagnose coronary artery disease when compared against the gold standard, acetylcholine angiogram.[10] This ... "Noninvasive identification of patients with early coronary atherosclerosis by assessment of digital reactive hyperemia". J Am ... "Circulation. 126 (6): 753-67. doi:10.1161/circulationaha.112.093245. PMC 3427943. PMID 22869857.. ...
The most common problem in FH is the development of coronary artery disease (atherosclerosis of the coronary arteries that ... "Circulation. 114 (24): 2710-38. doi:10.1161/CIRCULATIONAHA.106.179568. PMID 17130340.. *^ Müller C (1938). "Xanthoma, ... reduction in death from coronary heart disease to a point where people are no more likely to die of coronary heart disease than ... However, if the person already had coronary heart disease the reduction was 25%. The results emphasize the importance of early ...
In people with acute coronary syndrome, high-dose atorvastatin treatment may play a plaque-stabilizing role.[59][23] At high ... Shah RV, Goldfine AB (October 2012). "Statins and risk of new-onset diabetes mellitus". Circulation. 126 (18): e282-4. doi: ... May 2014). "Update on the efficacy of statin treatment in acute coronary syndromes". European Journal of Clinical Investigation ... Studies suggest that high-dose statin therapy may play a plaque-stabilizing role in people with acute coronary syndrome and ...
This is associated with the dominance of the coronary artery circulation. In right-dominant individuals the blood supply is ... The AV node lies at the lower back section of the interatrial septum near the opening of the coronary sinus, which conducts the ... The origin of this artery is most commonly (about 90% of hearts) a branch of the right coronary artery, with the remainder ... the coronary sinus, and the membranous part of the interatrial septum. The blood supply of the AV node is from the ...
Bezuidenhout, A. J. (1984). "The coronary circulation of the heart of the ostrich (Struthio camelus)". Journal of Anatomy. 138 ... The coronary arteries start in the right and left aortic sinus and provide blood to the heart muscle in a similar fashion to ... The blood supply by the coronary arteries are fashioned starting as a large branch over the surface of the heart. It then moves ... The deep branches of the coronary arteries found within the heart tissue are small and supply the interventricular and right ...
"Norepinephrine elicits beta2-receptor-mediated dilation of isolated human coronary arterioles". Circulation 106 (5): 550-5. ... "Coronary vasoconstriction mediated by α1- and α2-adrenoceptors in conscious dogs". Am. J. Physiol. 253 (2 Pt 2): H388-93. PMID ...
Coronary Angiography. Its Role in the Management of the Patient with Angina Pectoris. HAROLD A. BALTAXE, DAVID C. LEVIN ... Thank you for your interest in spreading the word on Circulation.. NOTE: We only request your email address so that the person ... The history, technic, and complications of coronary angiography have been discussed. Myocardial infarction caused by the ... Your Name) thought you would like to see the Circulation web site. ...
In these views, the whole coronary system is visualized from a single ostium, located at the right sinus. The right coronary ... This is a case of clinically benign single coronary artery, which should more properly be called single coronary ostium because ... Coronary Artery Anomalies. An Entity in Search of an Identity. Paolo Angelini ... Thank you for your interest in spreading the word on Circulation.. NOTE: We only request your email address so that the person ...
Selective coronary angiography demonstrated unobstructed tortuous coronary arteries. All 3 main coronary arteries drained into ... Multiple coronary artery fistulae arising from all 3 major coronary arteries emptying into the LV are extremely rare. There are ... Figure 2. Selective left coronary angiography in the anteroposterior projection demonstrating multiple coronary artery-left ... Multiple coronary LV fistulas: demonstration of coronary steal phenomenon by stress thallium scintigraphy and exercise ...
Prevalence of Subclinical Coronary Artery Disease Assessed by Coronary Computed Tomography Angiography in 45- to 55-Year-Old ... Prognostic Value of Coronary Artery Calcium in the PROMISE Study (Prospective Multicenter Imaging Study for Evaluation of Chest ... Angiography versus Hemodynamics to Predict the Natural History of Coronary Stenoses: A FAME 2-Substudy Giovanni Ciccarelli, ... Clinical Outcomes and Cost-Effectiveness of Fractional Flow Reserve-Guided Percutaneous Coronary Intervention in Patients With ...
Can Coronary Artery Calcification Testing Alone Safely Exclude ACS in Low-Risk Patients?. Coronary artery calcification (CAC) ... Coronary computed tomographic (CT) angiography (CTA) is a high-resolution, noninvasive technique to image the coronary arteries ... Coronary artery disease detected by coronary CT angiography is associated with intensification of preventive medical therapy ... B, Early imaging strategy implementing coronary CTA. CAD indicates coronary artery disease. Adapted from Cheezum et al11 with ...
Coronary Radiography and Endarterectomy. Postmortem Study of Feasibility of Surgery. NELSON R. NILES, CHARLES T. DOTTER ... Thank you for your interest in spreading the word on Circulation.. NOTE: We only request your email address so that the person ... In view of the frequency and mortality of coronary arteriosclerosis and because of the inadequacies of other methods of therapy ... Fluidtight closures permitted follow-up perfusion studies in 25 successful resections done for the relief of coronary luminal ...
... or coronary artery bypass surgery.. What Is Coronary Artery Bypass Surgery?. Coronary artery bypass surgery (CABG) involves ... Which Patients Need Coronary Artery Bypass Surgery?. Many patients with coronary artery disease will require more aggressive ... These deposits limit the flow of blood through the coronary arteries. Coronary artery disease often results in heart attack ( ... Coronary artery disease (also known as CAD) is the most common cardiovascular disorder in adults. It is caused by the build-up ...
... and the surgical observations regarding the status of the coronary arteries are compared with the coronary arteriographic ... Suprasternal Transaortic Coronary Arteriography. WILLIAM M. LEMMON, J. STAUFFER LEHMAN, RANDAL A. BOYER ... Opacification of the coronary arteries has been accomplished by direct needle puncture of the ascending portion of the thoracic ... Thank you for your interest in spreading the word on Circulation.. NOTE: We only request your email address so that the person ...
Coronary angiography revealed a long subocclusive lesion of the proximal right coronary artery. At that point, there was a ... Acute Coronary Syndromes. According to current guidelines, aspirin treatment is recommended definitively for acute coronary ... Percutaneous Coronary Intervention and Warfarin Treatment. Oral anticoagulation was routinely used for coronary stent ... Elective coronary angiography and percutaneous coronary intervention during uninterrupted warfarin therapy. Catheter Cardiovasc ...
Coronary Artery Computed Tomography Scanning. Carlo Nicola De Cecco, Felix G. Meinel, Salvatore A. Chiaramida, Philip Costello ... Coronary Artery Computed Tomography Scanning. Carlo Nicola De Cecco, Felix G. Meinel, Salvatore A. Chiaramida, Philip Costello ... Coronary Artery Computed Tomography Scanning. Carlo Nicola De Cecco, Felix G. Meinel, Salvatore A. Chiaramida, Philip Costello ... Thank you for your interest in spreading the word on Circulation.. NOTE: We only request your email address so that the person ...
Thank you for your interest in spreading the word on Circulation.. NOTE: We only request your email address so that the person ... Your Name) thought you would like to see the Circulation web site. ...
Stent thrombosis in the modern era: a pooled analysis of multicenter coronary stent clinical trials. Circulation. 2001; 103: ... Clinical end points in coronary stent trials: a case for standardized definitions. Circulation. 2007; 115: 2344-2351. ... Coronary artery bypass grafting is superior to percutaneous coronary intervention in prevention of perioperative myocardial ... A reanalysis of this trial comparing percutaneous coronary intervention with CABG suggested that percutaneous coronary ...
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Stroke Complicating Percutaneous Coronary Interventions. Shmuel Fuchs, Eugenio Stabile, Timothy D. Kinnaird, Gary S. Mintz, ... Stroke Complicating Percutaneous Coronary Interventions. Shmuel Fuchs, Eugenio Stabile, Timothy D. Kinnaird, Gary S. Mintz, ... Stroke after coronary artery bypass: incidence, predictors, and clinical outcome. Stroke. 2001; 32: 1508-1513. ... Stroke Complicating Percutaneous Coronary Interventions. Incidence, Predictors, and Prognostic Implications. Shmuel Fuchs, ...
Coronary Plaque Characterization in Psoriasis. Dario Kivelevitch, Jeffrey M. Schussler, Alan Menter ... Thank you for your interest in spreading the word on Circulation.. NOTE: We only request your email address so that the person ... Recent studies that used both noninvasive and invasive coronary artery studies of patients with psoriasis and have shown a ... Your Name) thought you would like to see the Circulation web site. ...
An anterior view of the heart shows the right coronary artery and the anterior descending branch of the left coronary ... Coronary+Vessels The coronary circulation is the circulation of blood in the blood vessels that supply blood to and from the ... coronary right coronary: SA nodal - AV nodal - atrial - right marginal - posterior interventricular. left coronary: anterior ... The coronary arteries are classified as "end circulation", since they represent the only source of blood supply to the ...
Coronary collaterals: an important and underexposed aspect of coronary artery disease. Circulation. 2003; 107: 2507-2511. ... Coronary collateral circulation: clinical significance and influence on survival in patients with coronary artery occlusion. Am ... significance for the development of the coronary artery collateral circulation. Circulation. 1999; 100: 547-552. ... Collateral circulation develops in some but not all patients with advanced coronary artery disease (CAD). Although the presence ...
Computed Tomography of the Coronary Arteries is a concise and easy-to-follow overview of the relevant concepts of CT coronary ... The book then covers coronary imaging, beginning with normal coronary anatomy (Chapter 3) and a review of the histological ... imaging of coronary anomalies, and bypass-graft imaging. There is also a chapter that reviews the data relevant to coronary ... The arrival of coronary CT has opened a new front in the seemingly perpetual to and fro between the cardiology and radiology ...
Dynamic mechanisms in human coronary stenosis.. B G Brown, E L Bolson, H T Dodge ... Thank you for your interest in spreading the word on Circulation.. NOTE: We only request your email address so that the person ... Third, a compliant arc of normal arterial wall borders part of the lumen in the majority of coronary lesions. This extremely ... At the clinical level, coronary stenoses frequently behave as though the obstruction to flow were variable and not as rigidly ...
Dietary iron intake and risk of coronary disease among men. Circulation. 1994;89:969-974. ... Salonen JT, Nyyssonen K, Salonen R. Body iron stores and the risk of coronary heart disease. N Engl J Med. 1994;331:1159-60. ... Iron status and coronary heart disease: negative findings from the NHANES I epidemiologic follow-up study. Am J Epidemiol. 1994 ... Coronary Heart Disease and Iron Status. Meta-Analyses of Prospective Studies. John Danesh, Paul Appleby ...
Early outcome after off-pump versus on-pump coronary bypass surgery: results from a randomized study. Circulation. 2001; 104: ... Coronary Heart Disease. One-Year Coronary Bypass Graft Patency. A Randomized Comparison Between Off-Pump and On-Pump Surgery ... Coronary Angiograms. Preoperative and 1-year follow-up coronary angiograms were done during a 2-day hospital stay with 6F ... benchmark for minimally invasive direct coronary artery bypass. Circulation. 1999; 100: 2353-2358. ...
Intracoronary angiotensin II potentiates coronary sympathetic vasoconstriction in humans. Circulation. 1997;96:148-153. ... Angiotensin II and Coronary Sympathetic Vasodilation. Kenneth M. Kessler, Rhonda M. Kessler ... Thank you for your interest in spreading the word on Circulation.. NOTE: We only request your email address so that the person ... Your Name) thought you would like to see the Circulation web site. ...
The aim of this pilot study was to test TI to visualize the coronary circulation of swine hearts. Thirty swine hearts were ... Coronary arteries were cannulated, namely the anterior interventricular artery, the circumflex branch of the left coronary ... These steps were repeated for each coronary vessel and under experimentally simulated coronary heart disease. Thermal imaging ... allowed a clear representation of the morphology and course of the coronary vessels and of experimentally simulated coronary ...
Contemporary percutaneous coronary intervention versus balloon angioplasty for multivessel coronary artery disease. Circulation ... Percutaneous recanalization of chronically occluded coronary arteries: a consensus document: part I. Circulation. 2005; 112: ... Percutaneous transluminal coronary angioplasty in chronic coronary artery occlusion. J Am Coll Cardiol. 1993; 21: 1371-1376. ... A randomized trial comparing coronary angioplasty with coronary bypass surgery. N Engl J Med. 1994; 331: 1044-1050. ...
Thank you for your interest in spreading the word on Circulation.. NOTE: We only request your email address so that the person ... Thrombolytic (Fibrinolytic) Therapy for Coronary Heart Disease. ANTHONY P. FLETCHER, SOL SHERRY ... Your Name) thought you would like to see the Circulation web site. ...
  • The exercise electrocardiogram was abnormal in each of 11 patients with markedly reduced coronary flow reserve (less than 2.5 peak/resting velocity) and in three of six patients with moderately reduced reserve (2.5-3.4 peak/resting velocity). (ahajournals.org)