Systole. Medical search

Period of contraction of the HEART, especially of the HEART VENTRICLES.

Post-systolic relaxation of the HEART, especially the HEART VENTRICLES.

Contractile activity of the MYOCARDIUM.

The valve between the left atrium and left ventricle of the heart.

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.

The graphic recording of chest wall movement due to cardiac impulses.

Ultrasonic recording of the size, motion, and composition of the heart and surrounding tissues. The standard approach is transthoracic.

A value equal to the total volume flow divided by the cross-sectional area of the vascular bed.

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.

The hemodynamic and electrophysiological action of the HEART VENTRICLES.

The hollow, muscular organ that maintains the circulation of the blood.

The volume of the HEART, usually relating to the volume of BLOOD contained within it at various periods of the cardiac cycle. The amount of blood ejected from a ventricle at each beat is STROKE VOLUME.

Measurement of intracardiac blood flow using an M-mode and/or two-dimensional (2-D) echocardiogram while simultaneously recording the spectrum of the audible Doppler signal (e.g., velocity, direction, amplitude, intensity, timing) reflected from the moving column of red blood cells.

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.

The hemodynamic and electrophysiological action of the LEFT ATRIUM.

Abnormal protrusion or billowing of one or both of the leaflets of MITRAL VALVE into the LEFT ATRIUM during SYSTOLE. This allows the backflow of blood into left atrium leading to MITRAL VALVE INSUFFICIENCY; SYSTOLIC MURMURS; or CARDIAC ARRHYTHMIA.

Timing the acquisition of imaging data to specific points in the cardiac cycle to minimize image blurring and other motion artifacts.

Echocardiography amplified by the addition of depth to the conventional two-dimensional ECHOCARDIOGRAPHY visualizing only the length and width of the heart. Three-dimensional ultrasound imaging was first described in 1961 but its application to echocardiography did not take place until 1974. (Mayo Clin Proc 1993;68:221-40)

Act of listening for sounds within the heart.

Backflow of blood from the LEFT VENTRICLE into the LEFT ATRIUM due to imperfect closure of the MITRAL VALVE. This can lead to mitral valve regurgitation.

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)

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.

The circulation of blood through the CORONARY VESSELS of the HEART.

The movement and the forces involved in the movement of the blood through the CARDIOVASCULAR SYSTEM.

Echocardiography applying the Doppler effect, with the superposition of flow information as colors on a gray scale in a real-time image.

The sounds heard over the cardiac region produced by the functioning of the heart. There are four distinct sounds: the first occurs at the beginning of SYSTOLE and is heard as a "lubb" sound; the second is produced by the closing of the AORTIC VALVE and PULMONARY VALVE and is heard as a "dupp" sound; the third is produced by vibrations of the ventricular walls when suddenly distended by the rush of blood from the HEART ATRIA; and the fourth is produced by atrial contraction and ventricular filling.

The hemodynamic and electrophysiological action of the HEART ATRIA.

PRESSURE of the BLOOD on the ARTERIES and other BLOOD VESSELS.

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.

Echocardiography applying the Doppler effect, with velocity detection combined with range discrimination. Short bursts of ultrasound are transmitted at regular intervals and the echoes are demodulated as they return.

A twisting deformation of a solid body about an axis. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)

The hemodynamic and electrophysiological action of the right HEART VENTRICLE.

The number of times the HEART VENTRICLES contract per unit of time, usually per minute.

The rhythmical expansion and contraction of an ARTERY produced by waves of pressure caused by the ejection of BLOOD from the left ventricle of the HEART as it contracts.

The pressure within a CARDIAC VENTRICLE. Ventricular pressure waveforms can be measured in the beating heart by catheterization or estimated using imaging techniques (e.g., DOPPLER ECHOCARDIOGRAPHY). The information is useful in evaluating the function of the MYOCARDIUM; CARDIAC VALVES; and PERICARDIUM, particularly with simultaneous measurement of other (e.g., aortic or atrial) pressures.

This structure includes the thin muscular atrial septum between the two HEART ATRIA, and the thick muscular ventricular septum between the two HEART VENTRICLES.

A form of CARDIAC MUSCLE disease, characterized by left and/or right ventricular hypertrophy (HYPERTROPHY, LEFT VENTRICULAR; HYPERTROPHY, RIGHT VENTRICULAR), frequent asymmetrical involvement of the HEART SEPTUM, and normal or reduced left ventricular volume. Risk factors include HYPERTENSION; AORTIC STENOSIS; and gene MUTATION; (FAMILIAL HYPERTROPHIC CARDIOMYOPATHY).

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.

The valve consisting of three cusps situated between the right atrium and right ventricle of the heart.

The chambers of the heart, to which the BLOOD returns from the circulation.

A fetal blood vessel connecting the pulmonary artery with the descending aorta.

Procedures in which placement of CARDIAC CATHETERS is performed for therapeutic or diagnostic procedures.

Rhythmic, intermittent propagation of a fluid through a BLOOD VESSEL or piping system, in contrast to constant, smooth propagation, which produces laminar flow.

Heart sounds caused by vibrations resulting from the flow of blood through the heart. Heart murmurs can be examined by HEART AUSCULTATION, and analyzed by their intensity (6 grades), duration, timing (systolic, diastolic, or continuous), location, transmission, and quality (musical, vibratory, blowing, etc).

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.

Resistance and recovery from distortion of shape.

The heart of the fetus of any viviparous animal. It refers to the heart in the postembryonic period and is differentiated from the embryonic heart (HEART/embryology) only on the basis of time.

Motion pictures of the passage of contrast medium through blood vessels.

A conical fibro-serous sac surrounding the HEART and the roots of the great vessels (AORTA; VENAE CAVAE; PULMONARY ARTERY). Pericardium consists of two sacs: the outer fibrous pericardium and the inner serous pericardium. The latter consists of an outer parietal layer facing the fibrous pericardium, and an inner visceral layer (epicardium) resting next to the heart, and a pericardial cavity between these two layers.

The valve between the left ventricle and the ascending aorta which prevents backflow into the left ventricle.

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.

Examinations used to diagnose and treat heart conditions.

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).

A purely physical condition which exists within any material because of strain or deformation by external forces or by non-uniform thermal expansion; expressed quantitatively in units of force per unit area.

A vasodilator that is administered by inhalation. It is also used recreationally due to its supposed ability to induce euphoria and act as an aphrodisiac.

A technique of inputting two-dimensional images into a computer and then enhancing or analyzing the imagery into a form that is more useful to the human observer.

The flow of BLOOD through or around an organ or region of the body.

Impaired conduction of cardiac impulse that can occur anywhere along the conduction pathway, such as between the SINOATRIAL NODE and the right atrium (SA block) or between atria and ventricles (AV block). Heart blocks can be classified by the duration, frequency, or completeness of conduction block. Reversibility depends on the degree of structural or functional defects.

Conical muscular projections from the walls of the cardiac ventricles, attached to the cusps of the atrioventricular valves by the chordae tendineae.

Changes in the observed frequency of waves (as sound, light, or radio waves) due to the relative motion of source and observer. The effect was named for the 19th century Austrian physicist Johann Christian Doppler.

Elements of limited time intervals, contributing to particular results or situations.

The failure by the observer to measure or identify a phenomenon accurately, which results in an error. Sources for this may be due to the observer's missing an abnormality, or to faulty technique resulting in incorrect test measurement, or to misinterpretation of the data. Two varieties are inter-observer variation (the amount observers vary from one another when reporting on the same material) and intra-observer variation (the amount one observer varies between observations when reporting more than once on the same material).

A type of imaging technique used primarily in the field of cardiology. By coordinating the fast gradient-echo MRI sequence with retrospective ECG-gating, numerous short time frames evenly spaced in the cardiac cycle are produced. These images are laced together in a cinematic display so that wall motion of the ventricles, valve motion, and blood flow patterns in the heart and great vessels can be visualized.

The circulation of the BLOOD through the LUNGS.

Pathological conditions involving the HEART including its structural and functional abnormalities.

Backflow of blood from the RIGHT VENTRICLE into the RIGHT ATRIUM due to imperfect closure of the TRICUSPID VALVE.

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.

The veins and arteries of the HEART.

The innermost layer of the heart, comprised of endothelial cells.

The range or frequency distribution of a measurement in a population (of organisms, organs or things) that has not been selected for the presence of disease or abnormality.

A pathological constriction that can occur above (supravalvular stenosis), below (subvalvular stenosis), or at the AORTIC VALVE. It is characterized by restricted outflow from the LEFT VENTRICLE into the AORTA.

Non-invasive imaging methods based on the mechanical response of an object to a vibrational or impulsive force. It is used for determining the viscoelastic properties of tissue, and thereby differentiating soft from hard inclusions in tissue such as microcalcifications, and some cancer lesions. Most techniques use ultrasound to create the images - eliciting the response with an ultrasonic radiation force and/or recording displacements of the tissue by Doppler ultrasonography.

Ultrasonic recording of the size, motion, and composition of the heart and surrounding tissues using a transducer placed in the esophagus.

Non-invasive method of demonstrating internal anatomy based on the principle that atomic nuclei in a strong magnetic field absorb pulses of radiofrequency energy and emit them as radiowaves which can be reconstructed into computerized images. The concept includes proton spin tomographic techniques.

Regulation of the rate of contraction of the heart muscles by an artificial pacemaker.

Ultrasonography applying the Doppler effect, with frequency-shifted ultrasound reflections produced by moving targets (usually red blood cells) in the bloodstream along the ultrasound axis in direct proportion to the velocity of movement of the targets, to determine both direction and velocity of blood flow. (Stedman, 25th ed)

The study of the deformation and flow of matter, usually liquids or fluids, and of the plastic flow of solids. The concept covers consistency, dilatancy, liquefaction, resistance to flow, shearing, thixotrophy, and VISCOSITY.

The main trunk of the systemic arteries.

A technique for assisting the circulation by decreasing the afterload of the left ventricle and augmenting the diastolic pressure. It may be achieved by intra-aortic balloon, or by implanting a special pumping device in the chest, or externally by applying a negative pressure to the lower extremities during cardiac systole.

Narrowing of the passage through the MITRAL VALVE due to FIBROSIS, and CALCINOSIS in the leaflets and chordal areas. This elevates the left atrial pressure which, in turn, raises pulmonary venous and capillary pressure leading to bouts of DYSPNEA and TACHYCARDIA during physical exertion. RHEUMATIC FEVER is its primary cause.

The short wide vessel arising from the conus arteriosus of the right ventricle and conveying unaerated blood to the lungs.

The process of generating three-dimensional images by electronic, photographic, or other methods. For example, three-dimensional images can be generated by assembling multiple tomographic images with the aid of a computer, while photographic 3-D images (HOLOGRAPHY) can be made by exposing film to the interference pattern created when two laser light sources shine on an object.

A type of heart valve surgery that involves the repair, replacement, or reconstruction of the annulus of the MITRAL VALVE. It includes shortening the circumference of the annulus to improve valve closing capacity and reinforcing the annulus as a step in more complex valve repairs.

A type of stress exerted uniformly in all directions. Its measure is the force exerted per unit area. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)

Any of the ruminant mammals with curved horns in the genus Ovis, family Bovidae. They possess lachrymal grooves and interdigital glands, which are absent in GOATS.

Methods developed to aid in the interpretation of ultrasound, radiographic images, etc., for diagnosis of disease.

A device that substitutes for a heart valve. It may be composed of biological material (BIOPROSTHESIS) and/or synthetic material.

A form of CARDIAC MUSCLE disease that is characterized by ventricular dilation, VENTRICULAR DYSFUNCTION, and HEART FAILURE. Risk factors include SMOKING; ALCOHOL DRINKING; HYPERTENSION; INFECTION; PREGNANCY; and mutations in the LMNA gene encoding LAMIN TYPE A, a NUCLEAR LAMINA protein.

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.

Three-dimensional representation to show anatomic structures. Models may be used in place of intact animals or organisms for teaching, practice, and study.

The veins that return the oxygenated blood from the lungs to the left atrium of the heart.

A combination of congenital heart defects consisting of four key features including VENTRICULAR SEPTAL DEFECTS; PULMONARY STENOSIS; RIGHT VENTRICULAR HYPERTROPHY; and a dextro-positioned AORTA. In this condition, blood from both ventricles (oxygen-rich and oxygen-poor) is pumped into the body often causing CYANOSIS.

Volume of circulating BLOOD. It is the sum of the PLASMA VOLUME and ERYTHROCYTE VOLUME.

A device designed to stimulate, by electric impulses, contraction of the heart muscles. It may be temporary (external) or permanent (internal or internal-external).

The visualization of tissues during pregnancy through recording of the echoes of ultrasonic waves directed into the body. The procedure may be applied with reference to the mother or the fetus and with reference to organs or the detection of maternal or fetal disease.

The properties, processes, and behavior of biological systems under the action of mechanical forces.

Enlargement of the LEFT VENTRICLE of the heart. This increase in ventricular mass is attributed to sustained abnormal pressure or volume loads and is a contributor to cardiovascular morbidity and mortality.

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).

Any disturbances of the normal rhythmic beating of the heart or MYOCARDIAL CONTRACTION. Cardiac arrhythmias can be classified by the abnormalities in HEART RATE, disorders of electrical impulse generation, or impulse conduction.

Improvement of the quality of a picture by various techniques, including computer processing, digital filtering, echocardiographic techniques, light and ultrastructural MICROSCOPY, fluorescence spectrometry and microscopy, scintigraphy, and in vitro image processing at the molecular level.

Computer-assisted processing of electric, ultrasonic, or electronic signals to interpret function and activity.

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.

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.

Pathological condition characterized by the backflow of blood from the ASCENDING AORTA back into the LEFT VENTRICLE, leading to regurgitation. It is caused by diseases of the AORTIC VALVE or its surrounding tissue (aortic root).

Treatment process involving the injection of fluid into an organ or tissue.

A computer based method of simulating or analyzing the behavior of structures or components.

The vessels carrying blood away from the heart.

An impulse-conducting system composed of modified cardiac muscle, having the power of spontaneous rhythmicity and conduction more highly developed than the rest of the heart.

Enlargement of the HEART, usually indicated by a cardiothoracic ratio above 0.50. Heart enlargement may involve the right, the left, or both HEART VENTRICLES or HEART ATRIA. Cardiomegaly is a nonspecific symptom seen in patients with chronic systolic heart failure (HEART FAILURE) or several forms of CARDIOMYOPATHIES.

A heterogeneous condition in which the heart is unable to pump out sufficient blood to meet the metabolic need of the body. Heart failure can be caused by structural defects, functional abnormalities (VENTRICULAR DYSFUNCTION), or a sudden overload beyond its capacity. Chronic heart failure is more common than acute heart failure which results from sudden insult to cardiac function, such as MYOCARDIAL INFARCTION.

A group of diseases in which the dominant feature is the involvement of the CARDIAC MUSCLE itself. Cardiomyopathies are classified according to their predominant pathophysiological features (DILATED CARDIOMYOPATHY; HYPERTROPHIC CARDIOMYOPATHY; RESTRICTIVE CARDIOMYOPATHY) or their etiological/pathological factors (CARDIOMYOPATHY, ALCOHOLIC; ENDOCARDIAL FIBROELASTOSIS).

Studies to determine the advantages or disadvantages, practicability, or capability of accomplishing a projected plan, study, or project.

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)

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.

The geometric and structural changes that the HEART VENTRICLES undergo, usually following MYOCARDIAL INFARCTION. It comprises expansion of the infarct and dilatation of the healthy ventricle segments. While most prevalent in the left ventricle, it can also occur in the right ventricle.

Substances used to allow enhanced visualization of tissues.

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.

The visualization of deep structures of the body by recording the reflections or echoes of ultrasonic pulses directed into the tissues. Use of ultrasound for imaging or diagnostic purposes employs frequencies ranging from 1.6 to 10 megahertz.

The age of the conceptus, beginning from the time of FERTILIZATION. In clinical obstetrics, the gestational age is often estimated as the time from the last day of the last MENSTRUATION which is about 2 weeks before OVULATION and fertilization.

Narrowing or constriction of a coronary artery.

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.

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).

Isopropyl analog of EPINEPHRINE; beta-sympathomimetic that acts on the heart, bronchi, skeletal muscle, alimentary tract, etc. It is used mainly as bronchodilator and heart stimulant.

A procedure consisting of a sequence of algebraic formulas and/or logical steps to calculate or determine a given task.

Striated muscle cells found in the heart. They are derived from cardiac myoblasts (MYOBLASTS, CARDIAC).

Radiography of the vascular system of the heart muscle after injection of a contrast medium.

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).

The gradual irreversible changes in structure and function of an organism that occur as a result of the passage of time.

NECROSIS of the MYOCARDIUM caused by an obstruction of the blood supply to the heart (CORONARY CIRCULATION).

Statistical models in which the value of a parameter for a given value of a factor is assumed to be equal to a + bx, where a and b are constants. The models predict a linear regression.

Computer-based representation of physical systems and phenomena such as chemical processes.

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.

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.

Either of the two principal arteries on both sides of the neck that supply blood to the head and neck; each divides into two branches, the internal carotid artery and the external carotid artery.

The measurement of an organ in volume, mass, or heaviness.

A basic element found in nearly all organized tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.

The status during which female mammals carry their developing young (EMBRYOS or FETUSES) in utero before birth, beginning from FERTILIZATION to BIRTH.

A statistical technique that isolates and assesses the contributions of categorical independent variables to variation in the mean of a continuous dependent variable.

Altered vascular reactivity following partial nephrectomy in the rat: a possible mechanism of the blood-pressure-lowering effect of heparin. (1/3311)

BACKGROUND: This study was designed to assess whether the antihypertensive effect of heparin in rats after renal mass reduction (RMR) is related to changes in nitric oxide activity, and to study in vitro the altered behaviour of resistance-sized arteries induced by chronic administration of heparin. METHODS: Male Wistar rats were assigned to one of two experimental protocols. In the first protocol, RMR rats received heparin (250 units/day s.c.) and tail systolic blood pressure (SBP) was measured weekly for 4 weeks. In a subgroup, urinary nitrate excretion (UNO3) and in vitro vascular reactivity of isolated perfused mesenteric arterial beds were measured 2 weeks after RMR. The second protocol assessed whether inhibition of NO synthesis with L-NAME (70 mg/l added to the drinking water) prevents the blood-pressure-lowering effect of heparin. RESULTS: In untreated RMR rats SBP increased from 111+/-3 mmHg to 127+/-5 mmHg at 2 weeks and 139+/-5 mmHg at 4 weeks. In contrast, in RMR rats treated with heparin, SBP was 114 +/-3 mmHg at 2 weeks and 115+/-4 mmHg at 4 weeks (P<0.05 for both). Treatment with L-NAME increased SBP both in untreated and heparin-treated RMR groups. Two weeks after nephrectomy daily urinary nitrate increased significantly more in RMR rats treated with heparin than in untreated RMR rats (22+/-2 vs 14.2+/-2.3 micromol/day, P<0.05). In vitro studies performed at 2 weeks showed that vessels of untreated RMR rats had a blunted vasodilator response to acetylcholine that was restored to levels similar to that of controls in the heparin-treated group. CONCLUSIONS: These results suggest that, in rats after renal ablation, heparin may exert its antihypertensive effect, at least in part, by affecting the altered behaviour of resistance vessels during the development phase of hypertension. Increased NO production may contribute to this effect. (+info)

Ambulatory blood pressure monitoring and progression in patients with IgA nephropathy. (2/3311)

BACKGROUND: Hypertension is a recognized marker of poor prognosis in IgA nephropathy. METHODS: The present study investigated the prevalence of white-coat hypertension, the diurnal rhythm of blood pressure (BP), the effectiveness of antihypertensive drug therapy, and the effect of the above on the progression of the kidney disease in IgA nephropathy. One hundred twenty-six IgA nephropathy patients were selected consecutively for 24-h ambulatory blood pressure monitoring (ABPM). Fifty-five patients were normotensive and 71 were treated hypertensives. Their antihypertensive drugs were angiotensin-converting enzyme inhibitors (ACEI) alone or in combination with calcium-channel blockers (CCB). RESULTS: The mean night-time BP of normotensives (108+/-9/67+/-6 mmHg) was significantly lower than their day-time BP (125+/-8/82+/-7 mmHg, P<0.05). There was no significant difference between the mean day-time and night-time BP in hypertensive patients (125+/-9/82+/-7 mmHg vs 128+/-10/85+/-9 mmHg). The circadian variation of BP was preserved ('dippers') in 82% of the normotensive and 7% of the hypertensive patients (P<0.001). There were 10 'white-coat hypertensives' among the patients classified as normotensives with ABPM (mean office blood pressure 149+/-7/96+/-8 mmHg, 24-h blood pressure 127+/-6/83+/-5 mmHg, P<0.05) and 14 among treated hypertensives (mean office BP 152+/-8/98+/-6 mmHg, 24-h BP 130+/-4/85+/-8 mmHg, P<0.05). There was no difference in mean day-time BP among normotensive and treated hypertensive patients (125+/-8/81+/-5 mmHg vs 128+/-10/85+/-9 mmHg). Hypertensives had significantly higher night-time BP (125+/-9/85+/-9 mmHg) than normotensives (108+/-9/67+/-6 mmHg, P<0.001). There was no difference in serum creatinine levels among the different groups at the time of the ABPM. However, thirty-six+/-4.1 months after the ABPM, hypertensive patients (n=52) had higher serum creatinine levels (124+/-32 micromol/l) than at the time of the ABPM (101+/-28 micromol/l). The serum creatinine of normotensive patients (n=43) did not change during the follow-up period. 'Non-dipper' normotensives (n=10) had significantly higher serum creatinine levels at the end of the follow-up period than at its beginning (106+/-17 micromol/l vs 89+/-18 micromol/l, P<0.05). There was no increase in serum creatinine of 'dipper' normotensives. The mean serum creatinine of 'white-coat hypertensives' was significantly higher at the end of the study period than at its beginning. CONCLUSIONS: There is no diurnal blood pressure variation in most of the hypertensive IgA nephropathy patients. ACEI and CCB treatment have better effect on day-time than night-time hypertension. The lack of the circadian rhythm and 'white-coat hypertension' seems to accelerate the progression of IgA nephropathy. (+info)

Effects of calcium-channel blockade in older patients with diabetes and systolic hypertension. Systolic Hypertension in Europe Trial Investigators. (3/3311)

BACKGROUND: Recent reports suggest that calcium-channel blockers may be harmful in patients with diabetes and hypertension. We previously reported that antihypertensive treatment with the calcium-channel blocker nitrendipine reduced the risk of cardiovascular events. In this post hoc analysis, we compared the outcome of treatment with nitrendipine in diabetic and nondiabetic patients. METHODS: After stratification according to center, sex, and presence or absence of previous cardiovascular complications, 4695 patients (age, > or =60 years) with systolic blood pressure of 160 to 219 mm Hg and diastolic pressure below 95 mm Hg were randomly assigned to receive active treatment or placebo. Active treatment consisted of nitrendipine (10 to 40 mg per day) with the possible addition or substitution of enalapril (5 to 20 mg per day) or hydrochlorothiazide (12.5 to 25 mg per day) or both, titrated to reduce the systolic blood pressure by at least 20 mm Hg and to less than 150 mm Hg. In the control group, matching placebo tablets were administered similarly. RESULTS: At randomization, 492 patients (10.5 percent) had diabetes. After a median follow-up of two years, the systolic and diastolic blood pressures in the placebo and active-treatment groups differed by 8.6 and 3.9 mm Hg, respectively, among the diabetic patients. Among the 4203 patients without diabetes, systolic and diastolic pressures differed by 10.3 and 4.5 mm Hg, respectively, in the two groups. After adjustment for possible confounders, active treatment was found to have reduced overall mortality by 55 percent (from 45.1 deaths per 1000 patients to 26.4 deaths per 1000 patients), mortality from cardiovascular disease by 76 percent, all cardiovascular events combined by 69 percent, fatal and nonfatal strokes by 73 percent, and all cardiac events combined by 63 percent in the group of patients with diabetes. Among the nondiabetic patients, active treatment decreased all cardiovascular events combined by 26 percent and fatal and nonfatal strokes by 38 percent. In the group of patients receiving active treatment, reductions in overall mortality, mortality from cardiovascular disease, and all cardiovascular events were significantly larger among the diabetic patients than among the nondiabetic patients (P=0.04, P=0.02, and P=0.01, respectively). CONCLUSIONS: Nitrendipine-based antihypertensive therapy is particularly beneficial in older patients with diabetes and isolated systolic hypertension. Thus, our findings do not support the hypothesis that the use of long-acting calcium-channel blockers may be harmful in diabetic patients. (+info)

Restriction of placental and fetal growth in sheep alters fetal blood pressure responses to angiotensin II and captopril. (4/3311)

1. We have measured arterial blood pressure between 115 and 145 days gestation in normally grown fetal sheep (control group; n = 16) and in fetal sheep in which growth was restricted by experimental restriction of placental growth and development (PR group; n = 13). There was no significant difference in the mean gestational arterial blood pressure between the PR (42.7 +/- 2.6 mmHg) and control groups (37.7 +/- 2.3 mmHg). Mean arterial blood pressure and arterial PO2 were significantly correlated in control animals (r = 0.53, P < 0.05, n = 16), but not in the PR group. 2. There were no changes in mean arterial blood pressure in either the PR or control groups in response to captopril (7.5 microg captopril min-1; PR group n = 7, control group n = 6) between 115 and 125 days gestation. After 135 days gestation, there was a significant decrease (P < 0.05) in the fetal arterial blood pressure in the PR group but not in the control group during the captopril infusion (15 microg captopril min-1; PR group n = 7, control group n = 6). 3. There was a significant effect (F = 14.75; P < 0.001) of increasing doses of angiotensin II on fetal diastolic blood pressure in the PR and control groups. The effects of angiotensin II were different (F = 8.67; P < 0.05) in the PR and control groups at both gestational age ranges. 4. These data indicate that arterial blood pressure may be maintained by different mechanisms in growth restricted fetuses and normally grown counterparts and suggests a role for the fetal renin-angiotensin system in the maintenance of blood pressure in growth restricted fetuses. (+info)

The diameter of the common femoral artery in healthy human: influence of sex, age, and body size. (5/3311)

PURPOSE: To determine the relevance of dilatations of the common femoral artery (CFA), knowledge of the normal CFA diameter is essential. The diameter of the CFA in healthy male and female subjects of different ages was investigated. METHODS: The diameter of the CFA was measured in 122 healthy volunteers (59 male, 63 female; 8 to 81 years of age) with echo-tracking B-mode ultrasound scan. The influence of age, sex, height, weight, body surface area (BSA), and systolic blood pressure was analyzed by means of a multiple regression model. RESULTS: The CFA increased steadily in diameter throughout life. From 25 years onwards, the diameter was larger in men than in women. Significant correlations were found between the CFA diameter and weight (r = 0.58 and r = 0.57 in male and female subjects, respectively; P <.0001), height (r = 0.49 and r = 0.54 in male and female subjects, respectively; P <.0001), and BSA (r = 0.60 and r = 0.62 in male and female subjects, respectively; P <.0001). Age and BSA were used to create a model for prediction of the CFA diameter (r = 0.71 and r = 0.77 in male and female subjects, respectively; P <.0001). CONCLUSION: The diameter of the CFA increases with age, initially during growth but also in adults. This is related to age, body size, and sex male subjects have larger arteries than female subjects. It is now possible to predict the normal CFA diameter, and nomograms that may be used in the study of aneurysmal disease are presented. (+info)

Acute exercise can improve cardioprotection without increasing heat shock protein content. (6/3311)

The aim of this study was to determine the effects of acute bouts of exercise on myocardial recovery after ischemia and heat shock protein expression. Adult female Sprague-Dawley rats were divided into five groups: 1) 1-day run (1DR; n = 6) and 2) 3-day run (3DR; n = 7), in which rats ran for 100 min at a speed of 20 m/min up a 6 degrees grade for 1 or 3 consecutive days; 3) 1-day cold run (1CR), in which rats ran the same as 1DR but with wet fur at 8 degrees C, which prevented an elevation of core temperature (n = 8); 4) heat shock sedentary (HS), in which rats had their core temperatures raised to 42 degrees C one time for 15 min (n = 5); and 5) sedentary control (n=15). Cardiac function was analyzed 24 h after the last treatment using an isolated, working heart model. Nonpaced hearts were initially perfused under normoxic conditions, then underwent 17 min of global, normothermic (37 degrees C) ischemia, and, finally, were allowed to recover for 30 min under normoxic conditions. The concentration of the 72-kDa heat shock protein (HSP 72) was measured in each left ventricle. Compared with that in the sedentary group, recovery of cardiac output x systolic pressure (CO x SP) was enhanced (P < 0.05) in all treatment groups when the postischemic value was covaried with the preischemic value. No differences in CO x SP were found (P > 0.05) between the following groups: 1DR vs. 3DR, 1DR vs. HS, and 1DR vs. 1CR. Heat shock protein concentration was significantly greater (P < 0.05) than that in the sedentary controls in HS, 1DR, and 3DR groups, but not for 1CR. The concentration of HSP 72 was not significantly correlated with postischemic CO x SP (R2 = 0.197, P > 0.05). We conclude that acute bouts of exercise can produce cardioprotective effects without an elevation of HSP 72. (+info)

Echocardiography-derived left ventricular end-systolic regional wall stress and matrix remodeling after experimental myocardial infarction. (7/3311)

OBJECTIVES: We tested the hypothesis that regional end-systolic left ventricular (ESLV) wall stress is associated with extracellular matrix remodeling activity after myocardial infarction (MI). BACKGROUND: Increased left ventricular (LV) wall stress is a stimulus for LV enlargement, and echocardiography can be used to estimate regional wall stress. A powerful validation of a noninvasive method of estimating wall stress would be predicting cellular responses after a MI. METHODS: Echocardiographic images were obtained in rats 1, 7, 14 or 21 days after coronary ligation (n = 11) or sham surgery (n = 5). End-systolic left ventricular wall stress was calculated by finite element analysis in three regions (infarcted, noninfarcted and border) from short-axis images. Matrix metalloproteinase-9 (MMP-9) and macrophage density were determined by immunohistochemistry, and positive cells were counted in high power fields (hpf). RESULTS: Average ESLV wall stress was higher in rats with MI when compared to shams irrespective of time point (p < 0.01), and ESLV wall stress in the infarcted regions increased with time (25.1 +/- 5.9 vs. 69.9 +/- 4.4 kdyn/cm2, day 1 vs. 21; p < 0.01). Matrix metalloproteinase-9 expression was higher in infarcted and border regions when compared to noninfarcted regions (22.1 vs. 25.7 vs. 0.10 cells/hpf, respectively; p < 0.01). Over all regions, ESLV wall stress was associated with MMP-9 (r = 0.76; p < 0.001), macrophage density (r = 0.72; p < 0.001) and collagen content (r = 0.67; p < 0.001). End-systolic left ventricular wall stress was significantly higher when MMP-9 positive cell density was greater than 10 cells/hpf (45+/-20 vs. 14+/-10 kdyn/cm2; p < 0.001). CONCLUSIONS: Regional increases in ESLV wall stress determined by echocardiography-based structural analysis are associated with extracellular matrix degradation activity. (+info)

Chordal force distribution determines systolic mitral leaflet configuration and severity of functional mitral regurgitation. (8/3311)

OBJECTIVES: The purpose of this study was to investigate the impact of the chordae tendineae force distribution on systolic mitral leaflet geometry and mitral valve competence in vitro. BACKGROUND: Functional mitral regurgitation is caused by changes in several elements of the valve apparatus. Interaction among these have to comply with the chordal force distribution defined by the chordal coapting forces (F(c)) created by the transmitral pressure difference, which close the leaflets and the chordal tethering forces (FT) pulling the leaflets apart. METHODS: Porcine mitral valves (n = 5) were mounted in a left ventricular model where leading edge chordal forces measured by dedicated miniature force transducers were controlled by changing left ventricular pressure and papillary muscle position. Chordae geometry and occlusional leaflet area (OLA) needed to cover the leaflet orifice for a given leaflet configuration were determined by two-dimensional echo and reconstructed three-dimensionally. Occlusional leaflet area was used as expression for incomplete leaflet coaptation. Regurgitant fraction (RF) was measured with an electromagnetic flowmeter. RESULTS: Mixed procedure statistics revealed a linear correlation between the sum of the chordal net forces, sigma[Fc - FT]S, and OLA with regression coefficient (minimum - maximum) beta = -115 to -65 [mm2/N]; p < 0.001 and RF (beta = -0.06 to -0.01 [%/N]; p < 0.001). Increasing FT by papillary muscle malalignment restricted leaflet mobility, resulting in a tented leaflet configuration due to an apical and posterior shift of the coaptation line. Anterior leaflet coapting forces increased due to mitral leaflet remodeling, which generated a nonuniform regurgitant orifice area. CONCLUSIONS: Altered chordal force distribution caused functional mitral regurgitation based on tented leaflet configuration as observed clinically. (+info)

Blood flow velocity refers to the speed at which blood flows through a blood vessel or artery. It is typically measured in units of meters per second (m/s) or centimeters per second (cm/s). Blood flow velocity is an important parameter in the assessment of cardiovascular health, as it can provide information about the functioning of the heart, blood vessels, and blood circulation. Blood flow velocity can be measured using various techniques, including Doppler ultrasound, magnetic resonance imaging (MRI), and computed tomography (CT) angiography. These techniques use sound waves or electromagnetic signals to detect the movement of blood through the blood vessels and calculate the velocity of blood flow. Abnormal blood flow velocities can indicate a variety of cardiovascular conditions, such as stenosis (narrowing) of the blood vessels, atherosclerosis (hardening of the arteries), and blood clots. Therefore, measuring blood flow velocity is an important diagnostic tool in the evaluation and management of cardiovascular diseases.

Cardiac volume refers to the amount of blood that is contained within the heart at any given time. It is an important parameter in the assessment of cardiac function and can be measured using various imaging techniques such as echocardiography, computed tomography (CT), and magnetic resonance imaging (MRI). There are three main types of cardiac volumes: stroke volume, end-diastolic volume, and end-systolic volume. Stroke volume is the amount of blood pumped out of the heart with each beat, while end-diastolic volume is the amount of blood in the heart at the end of the relaxation phase (diastole) of the cardiac cycle. End-systolic volume is the amount of blood remaining in the heart at the end of the contraction phase (systole) of the cardiac cycle. Abnormalities in cardiac volume can indicate various cardiac diseases or conditions, such as heart failure, valvular heart disease, or myocardial infarction (heart attack). Therefore, accurate measurement of cardiac volume is crucial for the diagnosis and management of these conditions.

In the medical field, "Atrial Function, Left" refers to the ability of the left atrium, one of the two upper chambers of the heart, to effectively contract and pump blood into the left ventricle. This is an important aspect of cardiac function, as the left atrium plays a crucial role in the circulation of blood throughout the body. Atrial function can be assessed through various imaging techniques, such as echocardiography or magnetic resonance imaging (MRI). Abnormalities in left atrial function can be associated with a variety of cardiovascular conditions, including atrial fibrillation, heart failure, and valvular heart disease. Therefore, evaluating left atrial function can provide important information for the diagnosis and management of these conditions.

Mitral Valve Prolapse (MVP) is a common heart condition in which the mitral valve, which is located between the left atrium and left ventricle of the heart, becomes enlarged or floppy. This can cause the valve to bulge or prolapse (push) into the left atrium during heartbeats, which can interfere with the normal flow of blood through the heart. MVP can be asymptomatic or may cause symptoms such as palpitations, shortness of breath, chest pain, and dizziness. In some cases, MVP can lead to more serious complications such as heart failure or abnormal heart rhythms. Treatment for MVP may include medications, lifestyle changes, or surgery, depending on the severity of the condition.

Cardiac-gated imaging techniques are medical imaging methods that use the beating of the heart to capture images of the heart and surrounding structures. These techniques are used to create high-quality images of the heart, even when the heart is moving rapidly or irregularly. The most common cardiac-gated imaging techniques are echocardiography, computed tomography (CT), and magnetic resonance imaging (MRI). In echocardiography, the ultrasound probe is placed on the chest, and the images are captured as the heart beats. In CT and MRI, the patient is placed inside a machine that generates X-rays or magnetic fields, and the images are captured as the heart beats. Cardiac-gated imaging techniques are used to diagnose a variety of heart conditions, including heart valve disease, coronary artery disease, and heart failure. They can also be used to monitor the effectiveness of treatments, such as cardiac surgery or medications. By capturing images of the heart at specific points in the cardiac cycle, these techniques can provide detailed information about the structure and function of the heart, which can help doctors make more accurate diagnoses and treatment decisions.

Mitral Valve Insufficiency (MVI) is a medical condition in which the mitral valve, which is located between the left atrium and left ventricle of the heart, does not close properly. This allows blood to flow back from the left ventricle into the left atrium, which can lead to an overload of blood in the left atrium and a decrease in the amount of blood flowing to the rest of the body. MVI can be caused by a variety of factors, including damage to the valve from infection, rheumatic fever, or high blood pressure, or it can be a result of a congenital defect. Symptoms of MVI may include shortness of breath, fatigue, chest pain, and swelling in the legs and ankles. Treatment for MVI may include medications to manage symptoms and improve heart function, or surgery to repair or replace the damaged valve.

The coronary circulation refers to the blood flow that supplies oxygen and nutrients to the heart muscle. It is a specialized network of blood vessels that branches off from the aorta, the main artery that carries oxygenated blood from the heart to the rest of the body. The coronary circulation is divided into two main branches: the left coronary artery and the right coronary artery. The left coronary artery supplies blood to the left side of the heart, including the left atrium, left ventricle, and the coronary arteries that branch off from it. The right coronary artery supplies blood to the right atrium and the right ventricle, as well as the coronary arteries that branch off from it. The coronary circulation is essential for maintaining the health and function of the heart muscle. If the blood flow to the heart is restricted or blocked, it can lead to a heart attack, which can be life-threatening. Therefore, the coronary circulation is closely monitored by healthcare professionals, and treatments such as angioplasty or bypass surgery may be necessary to restore blood flow to the heart.

Atrial function refers to the ability of the atria, the upper chambers of the heart, to effectively contract and pump blood into the ventricles, the lower chambers of the heart. This is an important aspect of cardiac function, as proper atrial function is necessary for efficient blood flow and overall heart health. There are several measures of atrial function, including: 1. Atrial electromechanical delay: This refers to the time it takes for electrical signals to travel from the sinoatrial node (the heart's natural pacemaker) to the atria and for the atria to contract. 2. Atrial volume: This refers to the amount of blood that is contained within the atria at any given time. 3. Atrial pressure: This refers to the force exerted by the atria on the ventricles during contraction. 4. Atrial compliance: This refers to the ability of the atria to expand and accommodate an increase in blood volume. Abnormalities in atrial function can be associated with a variety of cardiovascular conditions, including heart failure, atrial fibrillation, and valvular heart disease. Assessment of atrial function is often performed using echocardiography, a non-invasive imaging technique that allows for visualization of the heart's structure and function.

Blood pressure is the force exerted by the blood against the walls of the blood vessels as the heart pumps blood through the body. It is measured in millimeters of mercury (mmHg) and is typically expressed as two numbers: systolic pressure (the pressure when the heart beats) and diastolic pressure (the pressure when the heart is at rest between beats). Normal blood pressure is considered to be below 120/80 mmHg, while high blood pressure (hypertension) is defined as a systolic pressure of 140 mmHg or higher and/or a diastolic pressure of 90 mmHg or higher. High blood pressure is a major risk factor for heart disease, stroke, and other health problems.

Hypertrophic cardiomyopathy (HCM) is a type of heart disease characterized by the thickening of the heart muscle, particularly the walls of the left ventricle. This thickening can obstruct blood flow through the heart, leading to symptoms such as shortness of breath, chest pain, and fatigue. HCM can be caused by genetic mutations or be acquired as a result of other medical conditions or environmental factors. It is a common condition, affecting an estimated 1 in 500 people worldwide. Treatment for HCM may include medications, lifestyle changes, and in some cases, surgery or other procedures to improve blood flow and reduce the risk of complications.

Myocardial bridging is a rare condition in which a segment of the coronary artery is "bridged" by a band of myocardium (heart muscle). This means that the artery is physically covered by a layer of heart muscle, which can cause narrowing or obstruction of blood flow through the artery. This can lead to chest pain, shortness of breath, and other symptoms of heart disease. Myocardial bridging is usually diagnosed with an echocardiogram or coronary angiogram, and treatment may involve medications, lifestyle changes, or surgery in some cases.

Cardiac catheterization is a medical procedure that involves inserting a thin, flexible tube called a catheter into a blood vessel in the groin, arm, or neck and threading it up to the heart. The catheter is then used to inject a contrast dye into the heart's chambers and blood vessels, which allows doctors to see the heart's structure and function on X-ray images. The procedure is typically used to diagnose and treat a variety of heart conditions, including coronary artery disease, heart valve problems, and heart rhythm disorders. During the procedure, doctors may also perform additional tests, such as angiography, which involves taking X-ray images of the blood vessels to look for blockages or narrowing. Cardiac catheterization is generally considered a safe and minimally invasive procedure, with a low risk of complications. However, as with any medical procedure, there are some risks, including bleeding, infection, and damage to the blood vessels or heart.

Heart murmurs are abnormal sounds heard in the heart during auscultation, which is the process of listening to the heart with a stethoscope. These sounds are caused by turbulent blood flow within the heart or blood vessels, and they can be caused by a variety of conditions, including congenital heart defects, valvular heart disease, and heart infections. Heart murmurs can be classified into several types based on their characteristics, including systolic murmurs, diastolic murmurs, and continuous murmurs. Systolic murmurs occur during the contraction of the heart, while diastolic murmurs occur during the relaxation of the heart. Continuous murmurs occur throughout the cardiac cycle. The presence of a heart murmur does not necessarily indicate a serious condition, as many people have innocent murmurs that do not cause any problems. However, some heart murmurs may be indicative of a more serious underlying condition, such as a heart valve disorder or a congenital heart defect, and may require further evaluation and treatment.

Ventricular dysfunction, left, is a medical condition in which the left ventricle of the heart is unable to pump blood efficiently. The left ventricle is responsible for pumping oxygen-rich blood from the heart to the rest of the body. When it is not functioning properly, it can lead to a variety of symptoms, including shortness of breath, fatigue, and chest pain. There are several causes of left ventricular dysfunction, including heart attacks, high blood pressure, coronary artery disease, and heart valve problems. Treatment for left ventricular dysfunction depends on the underlying cause and may include medications, lifestyle changes, and in some cases, surgery. Left ventricular dysfunction can be a serious condition and requires prompt medical attention.

Cineangiography is a medical imaging technique used to visualize the blood flow in the arteries and veins of the body. It involves the injection of a contrast dye into the bloodstream, which makes the blood vessels visible on X-ray images. The images are then captured using a specialized camera and displayed on a monitor in real-time, allowing the physician to view the blood flow as it occurs. Cineangiography is commonly used to diagnose and treat a variety of cardiovascular conditions, including coronary artery disease, peripheral artery disease, and venous thrombosis. It can also be used to guide interventional procedures, such as angioplasty and stent placement, which are used to open blocked or narrowed blood vessels. The procedure typically involves the insertion of a catheter, a thin, flexible tube, into a blood vessel in the groin or arm. The catheter is then guided to the desired location using X-ray guidance, and the contrast dye is injected. The images are captured in real-time, allowing the physician to view the blood flow and any abnormalities. Cineangiography is a safe and effective diagnostic tool that has revolutionized the field of cardiovascular medicine. However, like all medical procedures, it carries some risks, including bleeding, infection, and damage to blood vessels.

The aortic valve is a one-way valve located at the exit of the left ventricle of the heart. It is responsible for preventing the backflow of blood from the aorta, the main artery that carries blood away from the heart, back into the left ventricle. The aortic valve is made up of three flaps, or cusps, that open and close in response to changes in pressure within the heart. When the left ventricle contracts, the aortic valve opens, allowing blood to flow into the aorta. When the left ventricle relaxes, the aortic valve closes, preventing blood from flowing back into the left ventricle. The aortic valve plays a critical role in maintaining the proper flow of blood throughout the body.

Cardiac output (CO) is a measure of the amount of blood that is pumped by the heart per minute. It is calculated by multiplying the heart rate (the number of times the heart beats per minute) by the stroke volume (the amount of blood pumped by each beat of the heart). Cardiac output is an important indicator of the body's ability to deliver oxygen and nutrients to the tissues and remove waste products. It is influenced by a number of factors, including the strength of the heart's contractions, the resistance of the blood vessels, and the volume of blood in the circulation. In the medical field, cardiac output is often measured using techniques such as echocardiography, thermodilution, or dye dilution. Abnormalities in cardiac output can be associated with a variety of medical conditions, including heart failure, anemia, and shock.

Amyl nitrite is a medication that is used to treat angina (chest pain) and to lower blood pressure in people with heart disease. It works by relaxing the blood vessels and increasing blood flow to the heart. Amyl nitrite is usually administered as a nasal spray and is used on an as-needed basis. It is not a long-term treatment for heart disease and should not be used to treat chest pain that is not related to angina. Amyl nitrite can cause side effects such as headache, flushing, and dizziness. It should not be used by people who are allergic to nitrites or who have certain types of heart disease.

Heart block is a condition in which the electrical signals that regulate the heartbeat are slowed or blocked as they travel through the heart's conduction system. This can cause the heart to beat too slowly (bradycardia) or irregularly, which can lead to symptoms such as dizziness, fainting, and shortness of breath. There are three main types of heart block: first-degree, second-degree, and third-degree. First-degree heart block is the mildest form and usually does not cause any symptoms. Second-degree heart block is more serious and can cause symptoms, especially if it is caused by an underlying heart condition. Third-degree heart block is the most serious form and can lead to life-threatening complications if not treated promptly. Heart block can be caused by a variety of factors, including damage to the heart muscle, certain medications, and inherited conditions. Treatment options depend on the severity of the heart block and the underlying cause. In some cases, a pacemaker may be necessary to regulate the heartbeat.

Heart diseases refer to a group of medical conditions that affect the heart and blood vessels. These conditions can range from minor to severe and can affect the heart's ability to pump blood effectively, leading to a variety of symptoms and complications. Some common types of heart diseases include: 1. Coronary artery disease: This is the most common type of heart disease, which occurs when the arteries that supply blood to the heart become narrowed or blocked due to the buildup of plaque. 2. Heart failure: This occurs when the heart is unable to pump enough blood to meet the body's needs. 3. Arrhythmias: These are abnormal heart rhythms that can cause the heart to beat too fast, too slow, or irregularly. 4. Valvular heart disease: This occurs when the heart valves become damaged or diseased, leading to problems with blood flow. 5. Congenital heart disease: This refers to heart defects that are present at birth. 6. Inflammatory heart disease: This includes conditions such as pericarditis and myocarditis, which cause inflammation of the heart. 7. Heart infections: These include conditions such as endocarditis and myocarditis, which can cause damage to the heart muscle and valves. Treatment for heart diseases depends on the specific condition and may include medications, lifestyle changes, and in some cases, surgery. Early detection and treatment are important for improving outcomes and reducing the risk of complications.

Tricuspid valve insufficiency (TVI) is a medical condition in which the tricuspid valve, which is located between the right atrium and right ventricle of the heart, does not close properly. This allows blood to flow back from the right ventricle into the right atrium, which can lead to a backup of blood in the right side of the heart and cause symptoms such as shortness of breath, fatigue, and swelling in the legs and ankles. TVI can be caused by a variety of factors, including damage to the valve from infection or injury, or as a result of certain medical conditions such as rheumatic fever or heart muscle disease. Treatment for TVI may include medications to reduce fluid buildup in the lungs and heart, or surgery to repair or replace the damaged valve.

Coronary vessels, also known as coronary arteries, are blood vessels that supply oxygen-rich blood to the heart muscle. There are two main coronary arteries, the left coronary artery and the right coronary artery, which branch off from the aorta and travel through the heart muscle to supply blood to the heart's various chambers and valves. The coronary arteries are responsible for delivering oxygen and nutrients to the heart muscle, which is essential for its proper function. If the coronary arteries become narrowed or blocked due to atherosclerosis (the buildup of plaque), it can lead to a condition called coronary artery disease (CAD), which can cause chest pain, heart attack, and other serious cardiovascular problems. In some cases, coronary artery disease can be treated with medications, lifestyle changes, or procedures such as angioplasty or coronary artery bypass surgery. It is important to maintain a healthy lifestyle, including regular exercise, a balanced diet, and not smoking, to reduce the risk of developing coronary artery disease and other cardiovascular problems.

Aortic valve stenosis is a medical condition in which the aortic valve, which is located between the left ventricle of the heart and the aorta, becomes narrowed or hardened, making it difficult for blood to flow from the heart to the rest of the body. This can lead to an increase in blood pressure in the left ventricle, which can cause the heart to work harder to pump blood through the narrowed valve. Over time, this can cause the heart muscle to become thickened and weakened, which can lead to heart failure. Aortic valve stenosis is typically caused by the buildup of calcium deposits or other substances on the valve, and it is more common in older adults. Treatment options for aortic valve stenosis may include medications, lifestyle changes, or surgery to replace the damaged valve.

Cardiac pacing, artificial refers to the medical procedure of implanting a device called a pacemaker into a patient's chest to regulate the heartbeat. The pacemaker is a small electronic device that sends electrical signals to the heart to prompt it to beat at a normal rate. The pacemaker is typically implanted under local anesthesia and can be done on an outpatient basis. The device is connected to the heart through wires called leads, which are placed in the heart's chambers. The pacemaker is then programmed to send electrical signals to the heart at specific intervals to ensure that the heart beats at a normal rate. Artificial cardiac pacing is commonly used to treat patients with bradycardia, a condition in which the heart beats too slowly. It can also be used to treat patients with certain heart conditions, such as heart failure, that cause the heart to beat irregularly. Artificial cardiac pacing can improve a patient's quality of life by reducing symptoms such as fatigue, dizziness, and shortness of breath.

The aorta is the largest artery in the human body, responsible for carrying oxygenated blood from the heart to the rest of the body. It is located in the chest and abdomen and is divided into three main sections: the ascending aorta, the aortic arch, and the descending aorta. The ascending aorta begins at the base of the heart and travels upward to the aortic arch. The aortic arch is a curved section of the aorta that arches over the top of the heart and connects to the descending aorta. The descending aorta continues downward from the aortic arch and eventually branches into smaller arteries that supply blood to the lower body. The aorta is an essential part of the circulatory system and plays a critical role in maintaining overall health and wellbeing. Any damage or disease affecting the aorta can have serious consequences, including heart attack, stroke, and even death.

Counterpulsation is a medical technique used to improve blood flow to the heart or other organs by using a device to pump blood in the opposite direction to the natural flow of blood. This technique is typically used in patients with severe heart failure or other conditions that affect the heart's ability to pump blood effectively. There are several types of counterpulsation devices, including intra-aortic balloon pumps (IABPs) and ventricular assist devices (VADs). IABPs are small, flexible balloons that are inserted into the aorta, the main artery that carries blood from the heart to the rest of the body. The balloons are inflated and deflated in synchronization with the patient's heartbeats, creating a "double pulse" effect that helps to improve blood flow to the heart and other organs. VADs are more complex devices that are typically used in patients with end-stage heart failure. These devices are surgically implanted into the patient's body and work by pumping blood from the heart's ventricles to the aorta, providing mechanical support to the heart and improving blood flow to the body. Counterpulsation devices are typically used as a bridge to transplantation or as a bridge to recovery in patients with severe heart failure. They can also be used in patients undergoing certain types of cardiac surgery, such as coronary artery bypass grafting, to help improve blood flow to the heart during the procedure.

Mitral Valve Stenosis (MVS) is a medical condition in which the mitral valve, which is located between the left atrium and left ventricle of the heart, becomes narrowed or stiffened. This can restrict the flow of blood from the left atrium to the left ventricle, making it harder for the heart to pump blood to the rest of the body. MVS can be caused by a variety of factors, including rheumatic fever, congenital heart defects, and certain infections or autoimmune diseases. Symptoms of MVS may include shortness of breath, fatigue, chest pain, and swelling in the legs and ankles. Treatment for MVS may include medications, lifestyle changes, and in some cases, surgery.

Dilated cardiomyopathy is a medical condition characterized by the enlargement and weakening of the heart muscle, specifically the ventricles, which are the lower chambers of the heart responsible for pumping blood out to the rest of the body. This enlargement causes the heart to become weakened and unable to pump blood efficiently, leading to symptoms such as shortness of breath, fatigue, and swelling in the legs and ankles. Dilated cardiomyopathy can be caused by a variety of factors, including genetics, infections, alcohol and drug abuse, and certain medications. It can also be a complication of other heart conditions, such as hypertension or coronary artery disease. Diagnosis of dilated cardiomyopathy typically involves a physical examination, electrocardiogram (ECG), echocardiogram, and other imaging tests. Treatment may include medications to improve heart function, lifestyle changes such as a heart-healthy diet and exercise, and in some cases, surgery or heart transplantation.

Dobutamine is a medication that is used to increase the strength of the heart's contractions and to increase the heart's rate. It is a synthetic form of dopamine, a hormone that is naturally produced by the body to help regulate blood pressure and heart function. Dobutamine is typically used to treat heart failure, a condition in which the heart is unable to pump blood effectively throughout the body. It is also sometimes used to treat low blood pressure (hypotension) and to increase blood flow to the heart muscle after a heart attack. Dobutamine is usually given intravenously, and the dosage is adjusted based on the patient's response and any side effects that may occur.

Tetralogy of Fallot (TOF) is a congenital heart defect that affects the structure of the heart and the flow of blood through it. It is the most common cyanotic congenital heart disease, meaning that it causes a bluish discoloration of the skin and mucous membranes due to the lack of oxygen in the blood. The term "tetralogy" refers to the four main features of the defect, which include: 1. Ventricular septal defect (VSD): A hole in the wall between the two lower chambers of the heart (the ventricles) that allows oxygen-poor blood to flow from the right ventricle to the left ventricle. 2. Pulmonary stenosis: A narrowing of the pulmonary valve, which regulates the flow of blood from the right ventricle to the lungs. 3. Overriding aorta: The aorta, which carries oxygen-rich blood from the heart to the rest of the body, is located on the right side of the heart instead of the left side, as it should be. 4. Right ventricular hypertrophy: The right ventricle of the heart is enlarged due to the increased workload of pumping oxygen-poor blood to the lungs. These four features work together to create a shunt, or a shortcut, in the heart that allows oxygen-poor blood to flow directly from the right ventricle to the aorta, bypassing the lungs. This can lead to a variety of symptoms, including shortness of breath, fatigue, and a bluish tint to the skin and mucous membranes. Treatment for TOF typically involves surgery to repair or replace the affected heart structures.

Blood volume refers to the total amount of blood present in the circulatory system of an individual. It is an important parameter in the medical field as it helps to regulate blood pressure, maintain fluid balance, and transport oxygen and nutrients to the body's tissues. The normal blood volume for an adult male is approximately 5 liters, while for an adult female, it is around 4.5 liters. Blood volume can be affected by a variety of factors, including dehydration, blood loss, fluid retention, and certain medical conditions such as heart failure or kidney disease. Measuring blood volume is typically done through a blood test called a hematocrit, which measures the percentage of red blood cells in the blood. Other methods of measuring blood volume include ultrasound, computed tomography (CT), and magnetic resonance imaging (MRI).

Biomechanical phenomena refer to the study of the mechanical properties and behavior of living organisms, particularly in relation to movement and function. In the medical field, biomechanical phenomena are often studied in the context of musculoskeletal disorders, sports injuries, and rehabilitation. This involves analyzing the forces and movements involved in various activities, such as walking, running, or lifting, and how they affect the body's tissues and structures. Biomechanical engineers and researchers use a variety of techniques, including computer simulations, imaging technologies, and physical measurements, to study biomechanical phenomena and develop new treatments and interventions for a range of medical conditions.

Hypertrophy, Left Ventricular refers to the thickening of the left ventricle, which is the main pumping chamber of the heart. This thickening can occur due to an increase in the workload on the heart, such as high blood pressure or a condition called aortic stenosis, or due to an underlying genetic disorder. Left ventricular hypertrophy can lead to heart failure, arrhythmias, and an increased risk of heart attack. It is typically diagnosed through an echocardiogram, a test that uses sound waves to create images of the heart. Treatment may include medications to lower blood pressure and reduce workload on the heart, as well as lifestyle changes such as exercise and a healthy diet. In severe cases, surgery may be necessary.

Myocardial ischemia is a medical condition that occurs when the blood flow to the heart muscle is reduced or blocked, leading to a lack of oxygen and nutrients to the heart cells. This can cause chest pain or discomfort, shortness of breath, and other symptoms. Myocardial ischemia is often caused by atherosclerosis, a condition in which plaque builds up in the arteries, narrowing or blocking the flow of blood. It can also be caused by other factors, such as heart valve problems or blood clots. Myocardial ischemia can be a serious condition and requires prompt medical attention to prevent heart attack or other complications.

Arrhythmias, cardiac refer to abnormal heart rhythms that are not synchronized with the electrical signals that control the heartbeat. These abnormal rhythms can be caused by a variety of factors, including structural abnormalities of the heart, damage to the heart muscle, or problems with the electrical conduction system of the heart. Arrhythmias can range from relatively harmless to life-threatening. Some common types of cardiac arrhythmias include atrial fibrillation, ventricular tachycardia, and atrial flutter. Symptoms of arrhythmias may include palpitations, shortness of breath, dizziness, or fainting. Treatment for arrhythmias may involve medications, lifestyle changes, or medical procedures such as catheter ablation or implantation of a pacemaker or defibrillator.

Aortic Valve Insufficiency (AVI) is a medical condition in which the aortic valve fails to close properly, allowing blood to flow back into the left ventricle of the heart. This can lead to a decrease in the amount of blood that is pumped out of the heart with each beat, which can cause symptoms such as shortness of breath, fatigue, and chest pain. AVI can be caused by a variety of factors, including damage to the valve from infection, high blood pressure, or aging. It can also be caused by certain medical conditions, such as rheumatic fever or Marfan syndrome. Treatment for AVI may include medications, lifestyle changes, or surgery, depending on the severity of the condition.

In the medical field, arteries are blood vessels that carry oxygenated blood away from the heart to the rest of the body. They are typically thick-walled and muscular, and their walls are lined with smooth muscle and elastic tissue that helps to maintain their shape and elasticity. There are three main types of arteries: 1. Ascending aorta: This is the largest artery in the body, and it carries oxygenated blood from the heart to the rest of the body. 2. Descending aorta: This artery carries oxygenated blood from the ascending aorta to the abdomen and lower extremities. 3. Coronary arteries: These arteries supply oxygenated blood to the heart muscle. Arteries are an essential part of the circulatory system, and any damage or blockage to them can lead to serious health problems, including heart attack and stroke.

Cardiomegaly is a medical condition characterized by an enlarged heart. The term "cardiomegaly" comes from the Greek words "kardia," meaning heart, and "mega," meaning large. Cardiomegaly can be caused by a variety of factors, including hypertension, valvular heart disease, myocardial infarction (heart attack), cardiomyopathy (disease of the heart muscle), and certain genetic disorders. The diagnosis of cardiomegaly is typically made through imaging tests such as echocardiography, chest X-rays, or computed tomography (CT) scans. Cardiomegaly can lead to a variety of complications, including heart failure, arrhythmias, and increased risk of stroke. Treatment depends on the underlying cause of the cardiomegaly and may include medications, lifestyle changes, and in some cases, surgery.

Heart failure, also known as congestive heart failure, is a medical condition in which the heart is unable to pump enough blood to meet the body's needs. This can lead to a buildup of fluid in the lungs, liver, and other organs, causing symptoms such as shortness of breath, fatigue, and swelling in the legs and ankles. Heart failure can be caused by a variety of factors, including damage to the heart muscle from a heart attack, high blood pressure, or long-term damage from conditions such as diabetes or coronary artery disease. It can also be caused by certain genetic disorders or infections. Treatment for heart failure typically involves medications to improve heart function and reduce fluid buildup, as well as lifestyle changes such as a healthy diet, regular exercise, and avoiding smoking and excessive alcohol consumption. In some cases, surgery or other medical procedures may be necessary to treat the underlying cause of the heart failure or to improve heart function.

Cardiomyopathies are a group of heart diseases that affect the heart muscle (myocardium). These diseases can cause the heart to become enlarged, thickened, or rigid, which can lead to problems with the heart's ability to pump blood effectively. There are several different types of cardiomyopathies, including: 1. Hypertrophic cardiomyopathy: This is a condition in which the heart muscle becomes abnormally thick, which can make it difficult for the heart to pump blood. 2. Dilated cardiomyopathy: This is a condition in which the heart muscle becomes weakened and enlarged, which can cause the heart to pump blood less effectively. 3. Arrhythmogenic right ventricular cardiomyopathy (ARVC): This is a condition in which the heart muscle in the right ventricle becomes abnormal and can cause irregular heart rhythms. 4. Non-ischemic dilated cardiomyopathy: This is a type of dilated cardiomyopathy that is not caused by a lack of blood flow to the heart muscle. 5. Idiopathic left ventricular hypertrophy: This is a condition in which the left ventricle of the heart becomes abnormally thick, which can make it difficult for the heart to pump blood. Cardiomyopathies can be inherited or acquired, and they can range from mild to severe. Treatment for cardiomyopathies depends on the specific type and severity of the condition, and may include medications, lifestyle changes, and in some cases, surgery.

Coronary disease, also known as coronary artery disease (CAD), is a condition in which the blood vessels that supply blood to the heart muscle become narrowed or blocked due to the buildup of plaque. This can lead to reduced blood flow to the heart, which can cause chest pain (angina), shortness of breath, and other symptoms. In severe cases, coronary disease can lead to a heart attack, which occurs when the blood flow to a part of the heart is completely blocked, causing damage to the heart muscle. Coronary disease is a common condition that affects many people, particularly those who are middle-aged or older, and is often associated with other risk factors such as high blood pressure, high cholesterol, smoking, and diabetes. Treatment for coronary disease may include lifestyle changes, medications, and in some cases, procedures such as angioplasty or coronary artery bypass surgery.

Ventricular remodeling refers to the structural and functional changes that occur in the heart's ventricles (the lower chambers of the heart) in response to various factors such as heart disease, injury, or genetic predisposition. These changes can include thickening of the heart muscle, enlargement of the ventricles, and changes in the electrical activity of the heart. Ventricular remodeling can lead to a variety of heart conditions, including heart failure, arrhythmias, and sudden cardiac death. It is a complex process that involves multiple cellular and molecular mechanisms, including inflammation, fibrosis, and changes in gene expression. In the medical field, ventricular remodeling is an important area of research, as it can help identify new targets for the prevention and treatment of heart disease. Treatment options for ventricular remodeling may include medications, lifestyle changes, and in some cases, surgical interventions.

Contrast media are substances that are used to enhance the visibility of certain structures or organs in medical imaging procedures, such as X-rays, computed tomography (CT), magnetic resonance imaging (MRI), and ultrasound. These substances are typically introduced into the body through injection, ingestion, or inhalation, and they work by altering the way that X-rays or other imaging waves interact with the tissues they pass through. There are several different types of contrast media, including iodinated contrast agents, gadolinium-based contrast agents, and barium sulfate. Iodinated contrast agents are the most commonly used type of contrast media and are typically used to enhance the visibility of blood vessels, organs, and other structures in the body. Gadolinium-based contrast agents are used in MRI scans to enhance the visibility of certain tissues, while barium sulfate is used in X-rays to outline the digestive tract. Contrast media are generally considered safe and effective when used appropriately, but they can cause side effects in some people, such as allergic reactions, nausea, and kidney problems. It is important for patients to discuss the potential risks and benefits of contrast media with their healthcare provider before undergoing an imaging procedure that involves the use of these substances.

Coronary stenosis is a medical condition in which the coronary arteries, which supply blood to the heart muscle, become narrowed or blocked. This can occur due to the buildup of plaque, a fatty substance that can accumulate on the inner walls of the arteries over time. When the arteries become narrowed, it can reduce the amount of blood and oxygen that reaches the heart muscle, which can lead to chest pain, shortness of breath, and other symptoms. Coronary stenosis is a common condition, particularly in older adults, and can be a serious health concern if left untreated. Treatment options for coronary stenosis may include medications, lifestyle changes, and procedures such as angioplasty or coronary artery bypass surgery.

Cardiotonic agents, also known as inotropic agents, are medications that increase the strength and force of contraction of the heart muscle. They are used to treat heart failure, a condition in which the heart is unable to pump enough blood to meet the body's needs. Cardiotonic agents work by increasing the sensitivity of the heart muscle to calcium, which is a key component of muscle contraction. This leads to an increase in the strength and force of the heart's contractions, allowing it to pump more blood and improve cardiac output. Some examples of cardiotonic agents include digitalis, dobutamine, and milrinone.

Isoproterenol is a synthetic beta-adrenergic agonist that is used in the medical field as a medication. It is a drug that mimics the effects of adrenaline (epinephrine) and can be used to treat a variety of conditions, including asthma, heart failure, and bradycardia (a slow heart rate). Isoproterenol works by binding to beta-adrenergic receptors on the surface of cells, which triggers a cascade of events that can lead to increased heart rate, relaxation of smooth muscle, and dilation of blood vessels. This can help to improve blood flow and oxygen delivery to the body's tissues, and can also help to reduce inflammation and bronchoconstriction (narrowing of the airways). Isoproterenol is available in a variety of forms, including tablets, inhalers, and intravenous solutions. It is typically administered as a short-acting medication, although longer-acting formulations are also available. Side effects of isoproterenol can include tremors, palpitations, and increased heart rate, and the drug may interact with other medications that affect the heart or blood vessels.

In the medical field, algorithms are a set of step-by-step instructions used to diagnose or treat a medical condition. These algorithms are designed to provide healthcare professionals with a standardized approach to patient care, ensuring that patients receive consistent and evidence-based treatment. Medical algorithms can be used for a variety of purposes, including diagnosing diseases, determining the appropriate course of treatment, and predicting patient outcomes. They are often based on clinical guidelines and best practices, and are continually updated as new research and evidence becomes available. Examples of medical algorithms include diagnostic algorithms for conditions such as pneumonia, heart attack, and cancer, as well as treatment algorithms for conditions such as diabetes, hypertension, and asthma. These algorithms can help healthcare professionals make more informed decisions about patient care, improve patient outcomes, and reduce the risk of medical errors.

Coronary angiography is a medical procedure used to diagnose and treat coronary artery disease (CAD). It involves injecting a contrast dye into the coronary arteries, which are the blood vessels that supply blood to the heart muscle. The dye makes the arteries visible on X-ray images, allowing doctors to see any blockages or narrowing of the arteries. During the procedure, a small catheter (a thin, flexible tube) is inserted into a blood vessel in the arm or leg and guided to the coronary arteries. The contrast dye is then injected through the catheter, and X-ray images are taken to visualize the arteries. Coronary angiography is often used to diagnose CAD, which is a common condition that can lead to heart attacks. It can also be used to guide treatment, such as angioplasty or stent placement, to open up blocked or narrowed arteries and improve blood flow to the heart.

In the medical field, aging refers to the natural process of physical, biological, and psychological changes that occur over time in living organisms, including humans. These changes can affect various aspects of an individual's health and well-being, including their metabolism, immune system, cardiovascular system, skeletal system, and cognitive function. Aging is a complex process that is influenced by a combination of genetic, environmental, and lifestyle factors. As people age, their bodies undergo a gradual decline in function, which can lead to the development of age-related diseases and conditions such as arthritis, osteoporosis, cardiovascular disease, diabetes, and dementia. In the medical field, aging is studied in the context of geriatrics, which is the branch of medicine that focuses on the health and well-being of older adults. Geriatricians work to identify and manage age-related health issues, promote healthy aging, and improve the quality of life for older adults.

Myocardial infarction (MI), also known as a heart attack, is a medical condition that occurs when blood flow to a part of the heart muscle is blocked, usually by a blood clot. This lack of blood flow can cause damage to the heart muscle, which can lead to serious complications and even death if not treated promptly. The most common cause of a heart attack is atherosclerosis, a condition in which plaque builds up in the arteries that supply blood to the heart. When a plaque ruptures or becomes unstable, it can form a blood clot that blocks the flow of blood to the heart muscle. Other causes of heart attacks include coronary artery spasms, blood clots that travel to the heart from other parts of the body, and certain medical conditions such as Kawasaki disease. Symptoms of a heart attack may include chest pain or discomfort, shortness of breath, nausea or vomiting, lightheadedness or dizziness, and pain or discomfort in the arms, back, neck, jaw, or stomach. If you suspect that you or someone else is having a heart attack, it is important to call emergency services immediately. Early treatment with medications and possibly surgery can help to reduce the risk of serious complications and improve the chances of a full recovery.

In the medical field, computer simulation refers to the use of computer models and algorithms to simulate the behavior of biological systems, medical devices, or clinical procedures. These simulations can be used to study and predict the effects of various medical interventions, such as drug treatments or surgical procedures, on the human body. Computer simulations in medicine can be used for a variety of purposes, including: 1. Training and education: Medical students and professionals can use computer simulations to practice and refine their skills in a safe and controlled environment. 2. Research and development: Researchers can use computer simulations to study the underlying mechanisms of diseases and develop new treatments. 3. Clinical decision-making: Physicians can use computer simulations to predict the outcomes of different treatment options and make more informed decisions about patient care. 4. Device design and testing: Engineers can use computer simulations to design and test medical devices, such as prosthetics or surgical instruments, before they are used in patients. Overall, computer simulations are a powerful tool in the medical field that can help improve patient outcomes, reduce costs, and advance medical knowledge.

Hypertension, also known as high blood pressure, is a medical condition in which the force of blood against the walls of the arteries is consistently too high. This can lead to damage to the blood vessels, heart, and other organs over time, and can increase the risk of heart disease, stroke, and other health problems. Hypertension is typically defined as having a systolic blood pressure (the top number) of 140 mmHg or higher, or a diastolic blood pressure (the bottom number) of 90 mmHg or higher. However, some people may be considered hypertensive if their blood pressure is consistently higher than 120/80 mmHg. Hypertension can be caused by a variety of factors, including genetics, lifestyle choices (such as a diet high in salt and saturated fat, lack of physical activity, and smoking), and certain medical conditions (such as kidney disease, diabetes, and sleep apnea). It is often a chronic condition that requires ongoing management through lifestyle changes, medication, and regular monitoring of blood pressure levels.

The carotid arteries are two major blood vessels in the neck that supply oxygenated blood to the brain and other parts of the head and neck. They are located on either side of the neck, just below the Adam's apple, and are responsible for approximately 15% of the total blood flow to the brain. The carotid arteries begin as two small arteries in the chest, called the internal carotid arteries, which then travel up the neck and join together to form the common carotid artery. The common carotid artery then branches off into the internal and external carotid arteries. The internal carotid artery supplies blood to the brain, while the external carotid artery supplies blood to the face, neck, and upper extremities. The carotid arteries are important for maintaining proper blood flow to the brain, which is essential for cognitive function, balance, and coordination. Damage or blockage of the carotid arteries can lead to serious health problems, including stroke.

Calcium is a chemical element with the symbol Ca and atomic number 20. It is a vital mineral for the human body and is essential for many bodily functions, including bone health, muscle function, nerve transmission, and blood clotting. In the medical field, calcium is often used to diagnose and treat conditions related to calcium deficiency or excess. For example, low levels of calcium in the blood (hypocalcemia) can cause muscle cramps, numbness, and tingling, while high levels (hypercalcemia) can lead to kidney stones, bone loss, and other complications. Calcium supplements are often prescribed to people who are at risk of developing calcium deficiency, such as older adults, vegetarians, and people with certain medical conditions. However, it is important to note that excessive calcium intake can also be harmful, and it is important to follow recommended dosages and consult with a healthcare provider before taking any supplements.

Analysis of Variance (ANOVA) is a statistical method used to compare the means of three or more groups. In the medical field, ANOVA can be used to compare the effectiveness of different treatments, interventions, or medications on a particular outcome or variable of interest. For example, a researcher may want to compare the effectiveness of three different medications for treating a particular disease. They could use ANOVA to compare the mean response (e.g., improvement in symptoms) between the three groups of patients who received each medication. If the results show a significant difference between the groups, it would suggest that one medication is more effective than the others. ANOVA can also be used to compare the means of different groups of patients based on a categorical variable, such as age, gender, or race. For example, a researcher may want to compare the mean blood pressure of patients in different age groups. They could use ANOVA to compare the mean blood pressure between the different age groups and determine if there are significant differences. Overall, ANOVA is a powerful statistical tool that can be used to compare the means of different groups in the medical field, helping researchers to identify which treatments or interventions are most effective and to better understand the factors that influence health outcomes.

As physicians, we rarely consider the healthy human body. We learn about normal human physiology during our first year... ...

https://www.thenewatlantis.com/practicing_medicine_tags/systole

심장은 수축(수축기(systole))과 이완(이완기(diastole))의 빠른 조정인 심장 주기라고 불리는 순서대로 리듬감 있게 박동합니다. ...

https://www.jove.com/science-education/10887/the-cardiac-cycle-systole-and-diastole?language=Korean

30 free 1-hour lectures on the highest yield USMLE Step I topics all in a QUESTION based manner

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In this talk we will discuss how to produce hyperbolic manifolds with large systole, and the impact in the topology of such ... The systole of a Riemannian manifold M is the length of a shortest non-contractible closed geodesic in M. ...

http://www.math.snu.ac.kr/board/index.php?mid=seminars&sort_index=speaker&order_type=desc&l=en&page=54&document_srl=803772

https://data.urenus.com/extra-systole/

G-protein-coupled receptor (GPCR) agonists are well-known inducers of cardiac hypertrophy. We found that the shedding of heparin-binding epidermal growth factor (HB-EGF) resulting from metalloproteinase activation and subsequent transactivation of the epidermal growth factor receptor occurred when c …

https://pubmed.ncbi.nlm.nih.gov/11786904/?dopt=Abstract

In this chapter, you will discover diseases that affect the cardiovascular system, the treatment of these diseases, and the effects on the clients general health status.

https://www.informit.com/articles/article.aspx?p=1746163&

Systole (SIS-te-lee):. Rhythmic contraction of the heart.. Thrombocyte (THROM-bow-site):. Platelet.. Vein (VAIN):. Vessel that ... While the ventricles are contracting (systole), the atria are at rest (diastole) and are filling with blood once again. When ... The contraction phase, especially of the ventricles, is known as systole; the relaxation phase is known as diastole. The ... It is higher during systole (left ventricle contracting) and lower during diastole (left ventricle relaxing). ...

https://www.encyclopedia.com/medicine/news-wires-white-papers-and-books/cardiovascular-system

Ventricular systole. *. Ventricular systole begins with the contraction of the left ventricle, which is caused by the spread of ... The cardiac cycle is divided into 2 phases: ventricular diastole and ventricular systole. ...

http://emedicine.medscape.com/article/88484-overview

Mitral regurgitation/During systole, contraction of the left ventricle causes abnormal back flow (arrow) into the left atrium ... IIIa: Leaflet motion restricted in both systole and diastole *. Caused by rheumatic heart disease commonly ... IIIb: Leaflet motion restricted in systole *. Caused by papillary muscle dysfunction or left ventricular dilation ... and/or papillary muscles causing leaflets to close insufficiently during systole[5] ...

https://www.ncbi.nlm.nih.gov/books/NBK553135/

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Top: peak systole; bottom: backflow. The single-lined Supera stent is out-of-plane halfway in the aneurysm. The color scale ... At the end of systole, the solenoid backflow valve opens, which creates a low-resistance pathway. The flow through the phantom ... Especially forward flow during systole was effectively diverted, promoting flow stasis in the aneurysm, as evidenced by the ... During flow reversal, the backward flow mixed with the vorticity generated during systole, creating complex flow features ( ...

https://link.springer.com/article/10.1007/s00270-022-03118-x

... left ventricular diastolic pressure and myocardial segment length and observations on the contribution of atrial systole. In: ... left ventricular diastolic pressure and myocardial segment length and observations on the contribution of atrial systole. ... left ventricular diastolic pressure and myocardial segment length and observations on the contribution of atrial systole., ... left ventricular diastolic pressure and myocardial segment length and observations on the contribution of atrial systole. ...

https://utsouthwestern.elsevierpure.com/en/publications/relatonship-between-left-ventricular-diastolic-pressure-and-myoca

e. LV septal thickness (end-systole). f. LV posterior wall (end-diastole; standard way). g. LV posterior wall (end-systole). h ... b. Left atrial size (end-systole). c. Aortic valve opening (mid-systole). d. LV septal thickness (end-diastole; standard way). ... c. LV volume (end-systole, 4-chamber, Simpsons rule). d. Ejection fraction (%). e. LA volume (end-systole; 4-chamber) ... i. LV internal dimension (end-systole). j. Mitral valve E-point-septal-separation. k. LV fractional shortening (%). l. Mitral ...

http://www.atsdr.cdc.gov/sites/vieques/heart_study_summary.html

Ventricular Systole. Echocardiography Reveals Movement of the Ventricular Walls and of the Valves ...

https://evolve.elsevier.com/cs/product/9780323594844?role=student

Topics include: ECG Complex; Electrical and Mechanical Sequence of a Heartbeat; Systole and Diastole; Configurations for Lead I ...

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Arterial blood supply to heart muscle is continuous whether the heart is in systole or diastole.. *. A. ... The statement is false because during systole (contraction phase of the heart), the coronary arteries are compressed, ...

https://www.proprofs.com/quiz-school/story.php?title=mtuyndcwmgf3ac

Size: Measure at end-diastole! (overestimation during systole). Large: , 2 cm. *Cardiac cycle. During systole and diastole: ...

https://www.nysora.com/news/identifying-pericardial-effusion-or-tamponade-a-guide-to-ultrasound-assessment-in-the-subcostal-4-chamber-view-s4c/

This period of contraction in the heart muscle is called systole. Blood pressure. If the terms systole and diastole sound ... This period of contraction in the heart muscle is called systole.\r\nBlood pressure\r\nIf the terms systole and diastole sound ... This period of contraction in the heart muscle is called ,i,systole,/i,.\r\n,h2 id=tab3 ,Blood pressure,/h2,\r\nIf the ... This period of contraction in the heart muscle is called ,i,systole,/i,.\r\n,h2 id=tab3 ,Blood pressure,/h2,\r\nIf the ...

https://www.dummies.com/article/academics-the-arts/science/biology/how-blood-flows-through-the-human-heart-194609/

Such stretching, he notes, occurs particularly during systole and in regions of damaged and weakened heart tissue. ...

https://www.medscape.com/viewarticle/783846

Yes, during systole. : And, no, during diastole.. Created for people with ongoing healthcare needs but benefits everyone. ...

https://www.healthtap.com/experts/10004941-dr-andrew-chung/

The reflection time index is the time from beginning of systole to the arrival of the reflected wave expressed as a fraction of ... A slower heart rate will cause the reflected wave peak to occur relatively earlier in systole, which will increase the AIx. ... The load on the ventricle during ejection is described by the pressure during systole. The contracting ventricle of a normal ... If wave reflection occurs during systole, it will increase the pressure against which the ventricle has to eject its contents. ...

https://karger.com/pls/article/4/4/180/274937/Large-Artery-Stiffness-Assessment-Using-SphygmoCor

TTE: moderate to severely reduced right-sided ventricular dysfunction, flattened interventricular septum in systole consistent ...

https://www.cdc.gov/mmwr/volumes/69/wr/mm6940e1.htm

The first is the systole, when the heart contracts and ejects blood into the arteries. ...

https://www.withings.com/jp/ja/health-insights/about-hypertension

Systole is the contraction phase of the cardiac cycle, and diastole is the relaxation phase. At a normal heart rate, one ...

https://www.daviddarling.info/encyclopedia/H/heart.html

Systole: Part of the normal beating of the heart where blood is pushed from the ventricles of the heart. This is known as the ...

http://infovets.com/books/Canine/I/Gloss.htm

Systole is when the heart is squeezing out blood and diastole is when it is filling up with blood.) ...

https://medlineplus.gov/ency/article/003266.htm

... occurs at the end of ventricular systole. The period between S1 and S2 is represents ventricular systole; the interval ... First (S1) and second (S2) heart sounds--S1 heralds the onset of ventricular systole. S1 is caused by closure of the mitral (M1 ... Ventricular systole follows closure of mitral and tricuspid valves (related to the 1st heart sound, S1). When ventricular ... The cardiac cycle consists of two periods: A) contraction (systole) when the heart ejects blood, and B) relaxation (diastole) ...

https://www.vin.com/apputil/project/defaultadv1.aspx?pid=11223&catid=&id=3858956&meta=generic&authorid=

systole- contraction- empty itself of blood. diastole- relaxation- to fill with blood. atrial systole-0.1 to 0.2 seconds- ... occurs at the beginning of systole when pressure increases, causes the AV valves to close, but is not yet high enough to push ...

https://www.flashcardmachine.com/circulatory-system-kd.html

It potentially affected by his left ventricular systole, infertility. A practical use of type of clinical endocrinologists, and ...

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Diastole Ventricular systole Cardiac cycle Ventricles Time

Systole is when the heart is squeezing out blood and diastole is when it is filling up with blood. (medlineplus.gov)
Blood pressure is measured both as the heart contracts, which is called systole, and as it relaxes, which is called diastole. (nih.gov)
Shunting across the interatrial septum is usually left-to-right and occurs predominantly in late ventricular systole and early diastole. (medscape.com)
Diastole -- The rhythmic relaxation and dilation of the heart chambers, during which time they fill with blood (cf. systole). (nih.gov)
Systole -- A rhythmically recurrent contraction of the heart by which the blood is forced onward and the circulation is kept up (cf. diastole). (nih.gov)
During each cardiac cycle, the heart goes through several different systole (contraction) and diastole (relaxing), cycles, and each of these cycles correspond to the signal wave produced during a cardiac cycle. (instructables.com)

ventricular systole lasted 200msec on the average. (cdc.gov)
Insufficiency of the mitral valve causing flow of blood from the left ventricle (LV) into the left atrium during ventricular systole. (merckmanuals.com)

While uncertainty due to RF noise has been incorporated into tractography algorithms and motion /eddy current distortion schemes exist, a further source of variability is the local displacement and distension of tissue1 occurring mainly during systole in the cardiac cycle. (nih.gov)

During systole, the ventricles contract and pump blood out of the heart, and the atria relax and begin filling with blood again. (msdmanuals.com)

Omecamtiv mecarbil is described as a cardiac-specific myosin activator that prolongs systole ejection time and thereby raises LVEF. (medscape.com)

Anatomy21

Organisms3

Diseases25

Chemicals and Drugs6

Analytical, Diagnostic and Therapeutic Techniques and Equipment50

Phenomena and Processes38

Disciplines and Occupations1

Technology, Industry, Agriculture1

Information Science8

Health Care9

Altered vascular reactivity following partial nephrectomy in the rat: a possible mechanism of the blood-pressure-lowering effect of heparin. (1/3311)

Ambulatory blood pressure monitoring and progression in patients with IgA nephropathy. (2/3311)

Effects of calcium-channel blockade in older patients with diabetes and systolic hypertension. Systolic Hypertension in Europe Trial Investigators. (3/3311)

Restriction of placental and fetal growth in sheep alters fetal blood pressure responses to angiotensin II and captopril. (4/3311)

The diameter of the common femoral artery in healthy human: influence of sex, age, and body size. (5/3311)

Acute exercise can improve cardioprotection without increasing heat shock protein content. (6/3311)

Echocardiography-derived left ventricular end-systolic regional wall stress and matrix remodeling after experimental myocardial infarction. (7/3311)

Chordal force distribution determines systolic mitral leaflet configuration and severity of functional mitral regurgitation. (8/3311)

Systole

Diastole

Myocardial Contraction

Mitral Valve

Heart Ventricles

Kinetocardiography

Echocardiography

Blood Flow Velocity

Ventricular Function, Left

Ventricular Function

Heart

Cardiac Volume

Echocardiography, Doppler

Models, Cardiovascular

Atrial Function, Left

Mitral Valve Prolapse

Cardiac-Gated Imaging Techniques

Echocardiography, Three-Dimensional

Heart Auscultation

Mitral Valve Insufficiency

Dogs

Stroke Volume

Coronary Circulation

Hemodynamics

Echocardiography, Doppler, Color

Heart Sounds

Atrial Function

Blood Pressure

Electrocardiography

Echocardiography, Doppler, Pulsed

Torsion, Mechanical

Ventricular Function, Right

Heart Rate

Pulse

Ventricular Pressure

Heart Septum

Cardiomyopathy, Hypertrophic

Myocardial Bridging

Tricuspid Valve

Heart Atria

Ductus Arteriosus

Cardiac Catheterization

Pulsatile Flow

Heart Murmurs

Ventricular Dysfunction, Left

Elasticity

Fetal Heart

Cineangiography

Pericardium

Aortic Valve

Myocardium

Heart Function Tests

Cardiac Output

Stress, Mechanical

Amyl Nitrite

Image Processing, Computer-Assisted

Regional Blood Flow

Heart Block

Papillary Muscles

Doppler Effect

Time Factors

Observer Variation

Magnetic Resonance Imaging, Cine

Pulmonary Circulation

Heart Diseases

Tricuspid Valve Insufficiency

Reproducibility of Results

Coronary Vessels

Endocardium

Reference Values

Aortic Valve Stenosis

Elasticity Imaging Techniques

Echocardiography, Transesophageal

Magnetic Resonance Imaging

Cardiac Pacing, Artificial

Ultrasonography, Doppler

Rheology

Aorta

Counterpulsation

Mitral Valve Stenosis