Contractile activity of the MYOCARDIUM.
A process leading to shortening and/or development of tension in muscle tissue. Muscle contraction occurs by a sliding filament mechanism whereby actin filaments slide inward among the myosin filaments.
The hemodynamic and electrophysiological action of the HEART VENTRICLES.
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.
Period of contraction of the HEART, especially of the HEART VENTRICLES.
The lower right and left chambers of the heart. The right ventricle pumps venous BLOOD into the LUNGS and the left ventricle pumps oxygenated blood into the systemic arterial circulation.
The hollow, muscular organ that maintains the circulation of the blood.
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.
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.
Ultrasonic recording of the size, motion, and composition of the heart and surrounding tissues. The standard approach is transthoracic.
The circulation of blood through the CORONARY VESSELS of the HEART.
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 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)
Striated muscle cells found in the heart. They are derived from cardiac myoblasts (MYOBLASTS, CARDIAC).
Muscular contractions characterized by increase in tension without change in length.
Contraction of the UTERINE MUSCLE.
Unstriated and unstriped muscle, one of the muscles of the internal organs, blood vessels, hair follicles, etc. Contractile elements are elongated, usually spindle-shaped cells with centrally located nuclei. Smooth muscle fibers are bound together into sheets or bundles by reticular fibers and frequently elastic nets are also abundant. (From Stedman, 25th ed)
Use of electric potential or currents to elicit biological responses.
A subtype of striated muscle, attached by TENDONS to the SKELETON. Skeletal muscles are innervated and their movement can be consciously controlled. They are also called voluntary muscles.
Muscle contraction with negligible change in the force of contraction but shortening of the distance between the origin and insertion.
The physiological narrowing of BLOOD VESSELS by contraction of the VASCULAR SMOOTH MUSCLE.
A common name used for the genus Cavia. The most common species is Cavia porcellus which is the domesticated guinea pig used for pets and biomedical research.
The nonstriated involuntary muscle tissue of blood vessels.
That phase of a muscle twitch during which a muscle returns to a resting position.
A state arrived at through prolonged and strong contraction of a muscle. Studies in athletes during prolonged submaximal exercise have shown that muscle fatigue increases in almost direct proportion to the rate of muscle glycogen depletion. Muscle fatigue in short-term maximal exercise is associated with oxygen lack and an increased level of blood and muscle lactic acid, and an accompanying increase in hydrogen-ion concentration in the exercised muscle.
Recording of the changes in electric potential of muscle by means of surface or needle electrodes.
A white crystal or crystalline powder used in BUFFERS; FERTILIZERS; and EXPLOSIVES. It can be used to replenish ELECTROLYTES and restore WATER-ELECTROLYTE BALANCE in treating HYPOKALEMIA.
The motor activity of the GASTROINTESTINAL TRACT.
The cartilaginous and membranous tube descending from the larynx and branching into the right and left main bronchi.
Drugs used to cause constriction of the blood vessels.
A movement, caused by sequential muscle contraction, that pushes the contents of the intestines or other tubular organs in one direction.
A musculomembranous sac along the URINARY TRACT. URINE flows from the KIDNEYS into the bladder via the ureters (URETER), and is held there until URINATION.
Contractile tissue that produces movement in animals.
Precursor of epinephrine that is secreted by the adrenal medulla and is a widespread central and autonomic neurotransmitter. Norepinephrine is the principal transmitter of most postganglionic sympathetic fibers and of the diffuse projection system in the brain arising from the locus ceruleus. It is also found in plants and is used pharmacologically as a sympathomimetic.
The relationship between the dose of an administered drug and the response of the organism to the drug.
A neurotransmitter found at neuromuscular junctions, autonomic ganglia, parasympathetic effector junctions, a subset of sympathetic effector junctions, and at many sites in the central nervous system.
The species Oryctolagus cuniculus, in the family Leporidae, order LAGOMORPHA. Rabbits are born in burrows, furless, and with eyes and ears closed. In contrast with HARES, rabbits have 22 chromosome pairs.
An alkaloid, originally from Atropa belladonna, but found in other plants, mainly SOLANACEAE. Hyoscyamine is the 3(S)-endo isomer of atropine.
An alpha-1 adrenergic agonist used as a mydriatic, nasal decongestant, and cardiotonic agent.
The excretory duct of the testes that carries SPERMATOZOA. It rises from the SCROTUM and joins the SEMINAL VESICLES to form the ejaculatory duct.
The distal and narrowest portion of the SMALL INTESTINE, between the JEJUNUM and the ILEOCECAL VALVE of the LARGE INTESTINE.
A potent vasodilator agent with calcium antagonistic action. It is a useful anti-anginal agent that also lowers blood pressure.
The portion of the descending aorta proceeding from the arch of the aorta and extending to the DIAPHRAGM, eventually connecting to the ABDOMINAL AORTA.
The state of activity or tension of a muscle beyond that related to its physical properties, that is, its active resistance to stretch. In skeletal muscle, tonus is dependent upon efferent innervation. (Stedman, 25th ed)
Cysts found in the jaws and arising from epithelium involved in tooth formation. They include follicular cysts (e.g., primordial cyst, dentigerous cyst, multilocular cyst), lateral periodontal cysts, and radicular cysts. They may become keratinized (odontogenic keratocysts). Follicular cysts may give rise to ameloblastomas and, in rare cases, undergo malignant transformation.
An antagonist of histamine that appears to block both H2 and H3 histamine receptors. It has been used in the treatment of ulcers.
An amine derived by enzymatic decarboxylation of HISTIDINE. It is a powerful stimulant of gastric secretion, a constrictor of bronchial smooth muscle, a vasodilator, and also a centrally acting neurotransmitter.
Drugs that bind to but do not activate histamine receptors, thereby blocking the actions of histamine or histamine agonists. Classical antihistaminics block the histamine H1 receptors only.
An adenine nucleotide containing one phosphate group which is esterified to both the 3'- and 5'-positions of the sugar moiety. It is a second messenger and a key intracellular regulator, functioning as a mediator of activity for a number of hormones, including epinephrine, glucagon, and ACTH.
Motion picture study of successive images appearing on a fluoroscopic screen.
An aspect of personal behavior or lifestyle, environmental exposure, or inborn or inherited characteristic, which, on the basis of epidemiologic evidence, is known to be associated with a health-related condition considered important to prevent.
Statistical models used in survival analysis that assert that the effect of the study factors on the hazard rate in the study population is multiplicative and does not change over time.
Studies in which subsets of a defined population are identified. These groups may or may not be exposed to factors hypothesized to influence the probability of the occurrence of a particular disease or other outcome. Cohorts are defined populations which, as a whole, are followed in an attempt to determine distinguishing subgroup characteristics.
Pathological conditions involving the CARDIOVASCULAR SYSTEM including the HEART; the BLOOD VESSELS; or the PERICARDIUM.
NECROSIS of the MYOCARDIUM caused by an obstruction of the blood supply to the heart (CORONARY CIRCULATION).

Myocardial uptake of digoxin in chronically digitalized dogs. (1/9164)

1 The time course of myocardial uptake of digoxin, increase in contractility and changes in myocardial potassium concentration was studied for 90 min following an intravenous digoxin dose to long-term digitalized dogs. 2 Nineteen dogs were investigated by the use of a biopsy technique which allowed sampling before and after administration of digoxin. 3 Ten minutes after administration of digoxin the myocardial concentration increased from 60 to 306 nmol/kg tissue, the myocardial concentration of digoxin was significantly lower (250 nmol/kg tissue) after 30 min and then increased again. 4 The transmural myocardial distribution of digoxin was uniform before and 90 min after administration of digoxin in long-term digitalized dogs but at 10 min after administration, both the subepicardial and the subendocardial concentration of digoxin were significantly lower than that of the mesocardial layer. 5 During the first 10 min the dp/dtmax increased to 135% of the control level. The increase remained unchanged during the rest of the study. 6 Myocardial potassium decreased throughout the study. 7 The M-configuration of the myocardial uptake curve and the non-uniformity of myocardial distribution of digoxin observed at 10 min after administrating digoxin to long-term digitalized dogs indicate that the distribution of myocardial blood flow may be changed during chronic digitalization.  (+info)

Ventricular pressure-volume curve indices change with end-diastolic pressure. (2/9164)

Many indices have been proposed to describee the diastolic pressure-volume curve mathematically and permit quantification of the elastic properties of the myocardium itself in hopes that changes in the muscle caused by disease would b.e reflected in the diastolic pressure-volume curve. To date, none of the proposed indices has been shown convincingly to discriminate one group of patients from another. While this situation in part arises from the relatively large amount of noise introduced by the technical difficulties of measuring synchronous pressures and volumes during diastole in man, ther is a more fundamental difficulty. In practice, one can measure only a short segment of the entire pressure-volume curve, and the values of all diastolic pressure-volume curve parameters investigated change significantly when one uses different segments of the same pressure-volume curve to compute them. These results were derived from relatively noise-free pressure-volume curves obtained by filling nine excised dog left ventricles at a known rate and monitoring pressure-volume curve used to compute the parameter. Merely increasing measurement fidelity will not resolve this problem, because none of these parameters accurately characterizes the entire diastolic pressure-volume curbe from a segment like that which one can reasonably expect to obtain from humans.  (+info)

The effect of cardiac contraction on collateral resistance in the canine heart. (3/9164)

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

Evaluation of the force-frequency relationship as a descriptor of the inotropic state of canine left ventricular myocardium. (4/9164)

The short-term force-frequency characteristics of canine left ventricular myocardium were examined in both isolated and intact preparations by briefly pertubing the frequency of contraction with early extrasystoles. The maximum rate of rise of isometric tension (Fmas) of the isolated trabeculae carneae was potentiated by the introduction of extrasystoles. The ratio of Fmas of potentiated to control beats (force-frequency ratio) was not altered significantly by a change in muscle length. However, exposure of the trabeculae to isoproterenol (10(-7)M) significantly changed the force-frequency ratio obtained in response to a constant frequency perturbation. Similar experiments were performed on chronically instrumented conscious dogs. Left ventricular minor axis diameter was measured with implanted pulse-transit ultrasonic dimension transducers, and intracavitary pressure was measured with a high fidelity micromanometer. Atrial pacing was performed so that the end-diastolic diameters of the beats preceding and following the extrasystole could be made identical. Large increases in the maximum rate of rise of pressure (Pmas) were seen in the contraction after the extrasystole. The ratio of Pmax of the potentiated beat to that of the control beat was not changed by a 9% increase in the end-diastolic diameter, produced by saline infusion. Conversely, isoproterenol significantly altered this relationship in the same manner as in the isolated muscle. Thus, either in vitro or in situ, left ventricular myocardium exhibits large functional changes in response to brief perturbations in rate. The isoproterenol and length data indicate that the force-frequency ratio reflects frequency-dependent changes in the inotropic state, independent of changes in length.  (+info)

Adenoviral gene transfer of the human V2 vasopressin receptor improves contractile force of rat cardiomyocytes. (5/9164)

BACKGROUND: In congestive heart failure, high systemic levels of the hormone arginine vasopressin (AVP) result in vasoconstriction and reduced cardiac contractility. These effects are mediated by the V1 vasopressin receptor (V1R) coupled to phospholipase C beta-isoforms. The V2 vasopressin receptor (V2R), which promotes activation of the Gs/adenylyl cyclase system, is physiologically expressed in the kidney but not in the myocardium. Expression of a recombinant V2R (rV2R) in the myocardium could result in a positive inotropic effect via the endogenous high concentrations of AVP in heart failure. METHODS AND RESULTS: A recombinant adenovirus encoding the human V2R (Ad-V2R) was tested for its ability to modulate the cardiac Gs/adenylyl cyclase system and to potentiate contractile force in rat ventricular cardiomyocytes and in H9c2 cardiomyoblasts. Ad-V2R infection resulted in a virus concentration-dependent expression of the transgene and led to a marked increase in cAMP formation in rV2R-expressing cardiomyocytes after exposure to AVP. Single-cell shortening measurements showed a significant agonist-induced contraction amplitude enhancement, which was blocked by the V2R antagonist, SR 121463A. Pretreatment of Ad-V2R-infected cardiomyocytes with AVP led to desensitization of the rV2R after short-term agonist exposure but did not lead to further loss of receptor function or density after long-term agonist incubation, thus demonstrating resistance of the rV2R to downregulation. CONCLUSIONS: Adenoviral gene transfer of the V2R in cardiomyocytes can modulate the endogenous adenylyl cyclase-signal transduction cascade and can potentiate contraction amplitude in cardiomyocytes. Heterologous expression of cAMP-forming receptors in the myocardium could lead to novel strategies in congestive heart failure by bypassing the desensitized beta-adrenergic receptor signaling.  (+info)

Myocardial oxygenation during high work states in hearts with postinfarction remodeling. (6/9164)

BACKGROUND: Postinfarction left ventricular remodeling (LVR) is associated with reductions in myocardial high-energy phosphate (HEP) levels, which are more severe in animals that develop overt congestive heart failure (CHF). During high work states, further HEP loss occurs, which suggests demand-induced ischemia. This study tested the hypothesis that inadequate myocyte oxygen availability is the basis for these HEP abnormalities. METHODS AND RESULTS: Myocardial infarction was produced by left circumflex coronary artery ligation in swine. Studies were performed in 20 normal animals, 14 animals with compensated LVR, and 9 animals with CHF. Phosphocreatine (PCr)/ATP was determined with 31P NMR and deoxymyoglobin (Mb-delta) with 1H NMR in myocardium remote from the infarct. Basal PCr/ATP tended to be decreased in postinfarct hearts, and this was significant in animals with CHF. Infusion of dobutamine (20 microg x kg-1 x min-1 IV) caused doubling of the rate-pressure product in both normal and LVR hearts and resulted in comparable significant decreases of PCr/ATP in both groups. This decrease in PCr/ATP was not associated with detectable Mb-delta. In CHF hearts, rate-pressure product increased only 40% in response to dobutamine; this attenuated response also was not associated with detectable Mb-delta. CONCLUSIONS: Thus, the decrease of PCr/ATP during dobutamine infusion is not the result of insufficient myocardial oxygen availability. Furthermore, in CHF hearts, the low basal PCr/ATP and the attenuated response to dobutamine occurred in the absence of myocardial hypoxia, indicating that the HEP and contractile abnormalities were not the result of insufficient oxygen availability.  (+info)

Hemodialysis with high-calcium dialysate impairs cardiac relaxation. (7/9164)

BACKGROUND: During hemodialysis (HD), serum ionized calcium is directly related to the dialysate calcium concentration. We have recently shown an acute induction of hypercalcemia to impair left ventricular (LV) relaxation. In the current study we sought to establish whether changes in serum Ca++ also affect LV function during HD. METHODS: We echocardiographically examined the LV relaxation and systolic function of 12 patients with end-stage renal disease before and after three HD treatments with dialysate Ca++ concentrations of 1.25 mmol/liter (dCa++1.25), 1.5 mmol/liter (dCa++1.50), and 1.75 mmol/liter (dCa++1.75), respectively. Age- and sex-matched healthy controls were also examined echocardiographically. RESULTS: The LV posterior wall thickness and the interventricular septum thickness, and the LV end-diastolic dimension and the end-systolic dimensions were significantly greater in the patients when compared with the controls, and the LV fractional shortening, the ratio of peak early to peak late diastolic velocities (E/Amax), and the isovolumic relaxation time (IVRT) showed impairment of LV relaxation and systolic function in the patients. Serum ionized calcium increased significantly during the dCa++1.5 HD (1.24 +/- 0.10 vs. 1.34 +/- 0.06 mmol/liter, P = 0. 004) and dCa++1.75 HD (1.19 +/- 0.10 vs. 1.47 +/- 0.06 mmol/liter, P = 0.002), and plasma intact parathyroid hormone decreased significantly during the dCa++1.75 HD (medians 8.2 vs. 2.7 pmol/liter, P = 0.002). LV systolic function was not altered during any of the treatments. The changes in E/Amax and IVRT suggested impairment of relaxation during all sessions, but only during the dCa++1.75 HD was the impairment statistically significant (E/Amax 1. 153 +/- 0.437 vs. 0.943 +/- 0.352, P < 0.05; IVRT 147 +/- 29 vs. 175 +/- 50 msecond, P < 0.05). CONCLUSION: HD with high-calcium (dCa++1. 75 mmol/liter) dialysate impairs LV relaxation when compared with lower calcium dialysate (dCa++1.25 and dCa++1.5 mmol/liter) treatments.  (+info)

Simultaneous assessment of effects of coronary vasodilators on the coronary blood flow and the myocardial contractility by using the blood-perfused canine papillary muscle. (8/9164)

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

Misrepresentation of left ventricular contractile function by endocardial indexes: clinical implications after coarctation repair. Am Heart J. 2000 Oct; 140(4):585-95 ...
Three indexes developed originally to assess left ventricular contractile performance were applied instead to the right ventricle (RV) in 11 conscious dogs: the relation between stroke work and end-diastolic volume (EDV), termed the preload recruitable stroke work (PRSW) relation; the end-systolic pressure-volume (ESPV) relation; and the maximum dP/dt (dP/dtmax)-EDV relation. The reproducibility, inotropic sensitivity, chronotropic sensitivity, and afterload sensitivity of these RV relations were compared. RV volume was determined with an ellipsoidal shell subtraction model from orthogonal dimensions measured by sonomicrometry. RV transmural pressure was measured with micromanometers. After autonomic blockade, preload was varied by repeated, transient vena caval occlusions before and during partial occlusion of the main pulmonary artery, after release of the pulmonary arterial occlusion, after calcium infusion, and over a range of heart rates induced by atrial pacing. The slope and volume-axis ...
TY - JOUR. T1 - Phosphoregulation of Cardiac Inotropy via Myosin Binding Protein-C during Increased Pacing Frequency or β1-Adrenergic Stimulation. AU - Tong, Carl W.. AU - Wu, Xin. AU - Liu, Yang. AU - Rosas, Paola C.. AU - Sadayappan, Sakthivel. AU - Hudmon, Andy. AU - Muthuchamy, Mariappan. AU - Powers, Patricia A.. AU - Valdivia, Héctor H.. AU - Moss, Richard L.. PY - 2015/5/4. Y1 - 2015/5/4. N2 - Background-Mammalian hearts exhibit positive inotropic responses to β-adrenergic stimulation as a consequence of protein kinase A-mediated phosphorylation or as a result of increased beat frequency (the Bowditch effect). Several membrane and myofibrillar proteins are phosphorylated under these conditions, but the relative contributions of these to increased contractility are not known. Phosphorylation of cardiac myosin-binding protein-C (cMyBP-C) by protein kinase A accelerates the kinetics of force development in permeabilized heart muscle, but its role in vivo is unknown. Such understanding is ...
TY - JOUR. T1 - Reversible myocardial contraction abnormalities in patients with an acute noncardiac illness. AU - Sharkey, Scott W.. AU - Shear, Wendy. AU - Hodges, Morrison. AU - Herzog, Charles A.. PY - 1998/1/1. Y1 - 1998/1/1. N2 - Study objectives: Reversible myocardial contraction abnormalities are usually observed in patients with acute ischemic syndromes caused by coronary artery disease. In this study, we report the occurrence of reversible anterior-apical contraction abnormalities in patients with an acute noncardiac illness. Setting: This was a retrospective study of 22 patients with the following characteristics: (1) hospitalization for an acute noncardiac illness; (2) appearance of deep T-wave inversion in the precordial leads of the ECG; and (3) presence of an anterior wall motion abnormality on an echocardiogram. Standard clinical information was collected together with results of serial ECGs, echocardiograms, and coronary angiograms. Results: The primary diagnoses for the 22 ...
The end-systolic elastance (Ees), the slope of the end-systolic pressure-volume relationship (ESPVR), has been used as an index of cardiac contractility. Although recent studies challenged the initial concept1 2 of linear and load-insensitive ESPVR by demonstrating contractility-dependent curvilinearity3 4 and load-dependence,5 6 Ees is still a powerful index to assess the inotropic state in experimental as well as clinical settings.7 8 9 10 The technical difficulties in measuring this index, however, prevent its widespread clinical acceptance. Difficulties include the need for a precise high-fidelity left ventricular (LV) volume curve as well as the need for multiple pressure-volume (P-V) loops under various loading conditions. Introduction of the conductance catheter9 11 12 and of the concept of a hydromotive pressure source13 14 for single-beat Ees estimation has partly solved these difficulties. Mirsky et al15 16 developed a single-beat method to assess myocardial contractility by fitting a ...
TY - JOUR. T1 - Myocardial contraction and relaxation. Role of anesthesia in depression and recovery during controlled regional ischemia. AU - Behrenbeck, T.. AU - Quasha, A. L.. AU - Tinker, J. H.. AU - Ritman, E. L.. PY - 1979/1/1. Y1 - 1979/1/1. UR - http://www.scopus.com/inward/record.url?scp=17544402207&partnerID=8YFLogxK. UR - http://www.scopus.com/inward/citedby.url?scp=17544402207&partnerID=8YFLogxK. M3 - Article. AN - SCOPUS:17544402207. VL - 27. SP - 671A. JO - Journal of Investigative Medicine. JF - Journal of Investigative Medicine. SN - 1081-5589. IS - 4. ER - ...
Journal of Diabetes Research is a peer-reviewed, Open Access journal that publishes research articles, review articles, and clinical studies related to type 1 and type 2 diabetes. The journal welcomes submissions focusing on the epidemiology, etiology, pathogenesis, management, and prevention of diabetes, as well as associated complications, such as diabetic retinopathy, neuropathy and nephropathy.
The present study provides strong evidence for a dual coupling of β2-AR to Gs and Gi protein at skeletal muscle, with a significant impact on muscle inotropic state. Of more importance, the secondary coupling of β2-AR to Gi protein seems to be indirect and dependent on extracellular degradation of cAMP into adenosine, which in turn activates muscle A1 adenosine receptors.. By studying the time course of clenbuterol and fenoterol effects on diaphragm twitch contraction, here we show that the well established β2-AR positive inotropism (Bowman and Nott, 1969) is attenuated after prolonged exposure (,30 min) to agonists (Figs. 1 and 2). At high concentrations of β2-AR agonists, the decline phase of inotropic effect was so intense that it abolished the positive inotropism.. The ability of PTX to attenuate the descending phase of β2-AR positive inotropism (Fig. 3) supports the idea of dual coupling of β-AR to Gs and Gi proteins, which seems to depend on the concentration and/or exposure time to ...
The twitch force (Ft)-interval relation of cardiac muscle reflects recovery of calcium release from the sarcoplasmic reticulum (SR). The calcium content of the SR is thought to be reflected by force developed during a contracture (Fc), induced by rapid cooling to near 0 degrees C. In right ventricular trabeculae of rat, under control conditions, the Ft-interval relation consisted of recovery of Ft to steady state (early recovery), followed by a secondary increase of Ft up to a maximum at an interval of approximately 100 seconds (rest potentiation) and a decline of Ft at intervals greater than 100 seconds (rest depression). The mechanisms that may underlie recovery of force after the last twitch at short intervals are 1) time-dependent transport of Ca2+ from the uptake compartment of the SR to the release compartment, 2) recovery of slow inward Ca2+ current during the action potential, and 3) recovery of the Ca2+ release channels in the SR. The Fc-interval relation was similar to the Ft-interval ...
Objectives: This study sought to determine significance of S100A1 genetically-targeted therapy in human failing myocardium focusing on the key pathological features emanating from contractile dysfunction and negative force-frequency response (FFR), blunted contractile reserve, susceptibility to arrhythmogenic Ca2+ leakage and impaired energy homeomostasis in failing ventricular cardiomyocytes.. Background: One pillar of heart failure (HF) is the depletion of the calcium (Ca2+) sensor protein S100A1 driving progressive deterioration of cardiac performance and transition to failure. Repairing this molecular defect by genetically-targeted S100A1 replacement in preclinical studies reversed the disease by restoring cardiomyocyte Ca2+ handling.. Methods and Results: S100A1 genetically-targeted therapy of isolated human failing cardiomyocytes (HFCMs) employing the human S100A1 cDNA both reversed contractile dysfunction and negative FFR due to normalized S100A1 protein expression. Therapeutic effects of ...
In this study, we provide two novel findings. First, we demonstrated that ISO is able to reduce force development without affecting the intracellular Ca2+ transient. For the first time, we show that ISO decreased Fmax and increased Ca50 of the steady-state force-Ca2+ relation in individual muscles, both before and after they were chemically skinned. Second, we demonstrated the ability of HNO donors such as NCA to rescue force development in ISO-treated muscles by virtue of their sensitizing action to Ca2+ at the myofilament level. This study extended the results from previous investigations on the effect of ISO on myocardial contractility while deepening our understanding of how ISO may dampen myocardial function.. The myofilament desensitizing effect of ISO (and/or sevoflurane) has been shown by a number of prior studies in intact cardiac muscles and myocytes (Hanley and Loiselle, 1998; Jiang and Julian, 1998; Graham et al., 2005). ISO may decrease myofilament Ca2+ responsiveness by 1) directly ...
Omecamtiv mecarbil (AMG 423, CK-1827452) is a novel small molecule that increases cardiac contractility by selectively and directly activating the enzymatic domain of cardiac myosin heavy chain, the force-generating motor protein of the cardiac sarcomere. This is a randomized, placebo-controlled, multicenter, phase 2 study, consisting of a dose escalation phase to select 1 of 3 omecamtiv mecarbil oral formulations in 2 dose escalation cohorts, followed by an expansion phase to evaluate 20 weeks of administration of the selected omecamtiv mecarbil formulation at 2 target dose levels, compared with placebo ...
Progressive deterioration of cardiac contractility is a central feature of congestive heart failure (CHF) in humans. In this report we review those studies that have addressed the idea that alterations of intracellular calcium (Ca(2+)) regulation is primarily responsible for the depressed contractility of the failing heart. The review points out that Ca(2+)transients and contraction are similar in non-failing and failing myocytes at very slow frequencies of stimulation (and other low stress environments). Faster pacing rates, high Ca(2+)and beta-adrenergic stimulation reveal large reductions in contractile reserve in failing myocytes. The underlying cellular basis of these defects is then considered. Studies showing changes in the abundance of L-type Ca(2+)channels, Ca(2+)transport proteins [sarcoplasmic reticulum Ca(2+)ATPase (SERCA2), phospholamban (PLB), Na(+)/Ca(2+) exchanger (NCX)] and Ca(2+) release channels (RYR) in excitation-contraction coupling and Ca(2+)release and uptake by the sarcoplasmic
During further development the ability of sarcoplasmic reticulum to accumulate Ca2+ increases and there is a progressive maturation of Ca2+ release from the
Genetically manipulated animals like mice or rabbits play an important role in the exploration of human cardiovascular diseases. It is therefore important to identify animal models that closely mimic physiological and pathological human cardiac function. In-vivo phase contrast cardiovascular magnetic resonance (CMR) was used to measure regional three-directional left ventricular myocardial motion with high temporal resolution in mice (N=18), rabbits (N=8), and humans (N=20). Radial, long-axis, and rotational myocardial velocities were acquired in left ventricular basal, mid-ventricular, and apical short-axis locations. Regional analysis revealed different patterns of motion: 1) In humans and rabbits, the apex showed slower radial velocities compared to the base. 2) Significant differences within species were seen in the pattern of long-axis motion. Long-axis velocities during systole were fairly homogeneously distributed in mice, whereas humans showed a dominant component in the lateral wall and rabbits
Cardiovascular disease generally refers to conditions that involve narrowed or blocked blood vessels that can lead to a heart attack, chest pain (angina) or stroke. Diseases under the cardiovascular disease umbrella include blood vessel diseases, such as coronary artery disease; heart rhythm problems (arrhythmias); and heart defects youre born with (congenital heart defects), among others.. Atrial fibrillation (AF, or A-fib) is a disorder in which the normally regular and coordinated contraction pattern of the hearts two small upper chambers, or the atria, becomes irregular and uncoordinated. The irregular contraction pattern associated with AF causes blood to pool in the atria, predisposing the formation of clots potentially resulting in stroke. In addition, AF increases the risk of stroke and may also contribute to worsening heart failure.. AF is considered an epidemic cardiovascular disease. The estimated number of individuals with AF globally in 2010 was 33.5 million. According to the ...
Taken together, our data suggest that aging and obesity compromise cardiac contractile function possibly via phosphorylation of Akt, eNOS and stress signaling-associated O2(-) release.
TY - JOUR. T1 - The power of metabolism - Linking energy supply and demand with cardiac contractile function. AU - Schwarzer, Michael. AU - Doenst, Torsten. AU - Des Rosiers, Christine. AU - Glatz, Jan F. C.. PY - 2019/4/1. Y1 - 2019/4/1. U2 - 10.1016/j.bbadis.2019.02.006. DO - 10.1016/j.bbadis.2019.02.006. M3 - Editorial. VL - 1865. SP - 725. EP - 727. JO - Biochimica et Biophysica Acta-Molecular Basis of Disease. JF - Biochimica et Biophysica Acta-Molecular Basis of Disease. SN - 0925-4439. IS - 4. ER - ...
in Computer Methods & Programs in Biomedicine (2013), 109(2), Estimation of ventricular contractility and ventricular arterial coupling is clinically important in diagnosing and treating cardiac dysfunction in the critically ill. However, experimental assessment of ... [more ▼]. Estimation of ventricular contractility and ventricular arterial coupling is clinically important in diagnosing and treating cardiac dysfunction in the critically ill. However, experimental assessment of indexes of ventricular contractility, such as the end-systolic pressure-volume relationship, requires a highly invasive maneuver and measurements that are not typical in an intensive care unit (ICU). This research describes the use of a previously validated cardiovascular system model and parameter identification process to evaluate the right ventricular arterial coupling in septic shock. Model-based ventricular arterial coupling is defined by the ratio of the end systolic right ventricular elastance (E(esrvf)) over ...
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DA)(DA)(DA)(DA) (DA)(DA)(DA)(DG)(DC)(DT)(DG)(DC)(DA). Chain J,T. (DG)(DC)(DT)(DT)(DT)(DT)(DT)(DT)(DT)(DT)(DT)(DT)(DC)(DA)(DC)(DA)(DA)(DT)(DC)(DC) (DC)(DG ...
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The multicellular organismal process in which the heart decreases in volume in a characteristic way to propel blood through the body. [GOC:dph]
Mechanistic studies will provide insight into how CCM improves LV function. We observed that CCM did not just augment contractility at the septal and adjacent walls where the 2 electrodes were placed; rather, systolic function was enhanced in the entire LV including the free-wall segments. Therefore, in the long run, the concerted force in all 6 regions of the LV would contribute to the improvement of LV global systolic function, resulting in LV reverse remodeling and reduction of mitral regurgitation. These findings are completely consistent with a recent report concerning CCM-induced reverse molecular remodeling (8). When HF was experimentally induced in animals, there was a switch in expression of a host of genes from a normal adult genotype to a fetal genotype indicative of myocardial pathology. In such animals, Imai et al. (8) showed that within hours of initiating CCM signal delivery, there was a reversion back towards a normal genotype only in the region of the heart where signals were ...
In this study we will investigate a method combining transoesophageal echocardiography and non-invasive finger arterial blood pressure waveforms to non-invasively construct pressure-volume (P-V) loops to describe the end-systolic pressure-volume relations in the heart. This may provide a method to obtain more insight on cardiac contractile function and the interaction of the heart with the vasculature during surgery ...
High performance computing in multiscale modeling cardiac contraction: Bridging proteins to cells to whole heart . J. Jeremy Rice. Computational Biology Center Thomas J. Watson Research Center [email protected] Motivation. Slideshow 88620 by HarrisCezar
Quantification of cardiovascular flow and motion is essential in the diagnosis, treatment and follow-up of cardiovascular disease. The accuracy and quantification of many imaging methods used in this field have important shortfalls, however, that result from limitations in spatial and temporal dimensions. Improvement in application of these methods requires an in-depth understanding of the technical and perceptual aspects that contribute to errors in their use.. Visual assessment of echocardiographic images for asynchrony in regional myocardial motion during systolic contraction is an example of the need for better definition of limitations. The discernible delay in wall motion improved from 89 ms to 71 ms by allowing side-by-side comparison to normal motion. Clinically important delays are almost certainly missed with current eyeballing methods. Different and more quantitative approaches to this problem have been developed. Anatomic M-mode (AMM) assesses motion along an arbitrary line within ...
Contraction and Unwinding of Cardiac Fibres. Work group of Physiology and Pharmacology, School of Agriculture, Faisalabad. The mammalian core pumping systems the our blood all over the frame by speedily maintaining the pumping move throughout fast adjustment in system metabolic expectations. A persons heart and soul performs its action without the need of sophistication. Many different experiments have most certainly been undertaken about the activities of heart and soul in strong and unhealthy regions that can be required to figure out some creative treatment plans so that you can enhance and extend activities of affected individuals. Puppy models are employed commonly in cardiac exploration to analyze and examine many types of core operations and restorative label (Nima and Paul, 2014).. http://bestessaysforsale.net/term-paper-writing-service/ Cardiac contraction and relaxations are governed by Calcium. The position of calcium for myocardial contraction slowly became obvious because of the ...
BioAssay record AID 218832 submitted by ChEMBL: Tested for beta-1-adrenergic blocking effect by measuring the ability to inhibit the positive inotropic effect of isoproterenol on the isolated right atrium of guinea pigs.
The MMC has been likened to a housekeeper. A housekeeper comes in after the feast and cleans up the place, restoring the environment. It has been suggested that the MMC may exist to clean the digestive tract of residual food, secretions, and cellular debris.2 An increase in secretions from the stomach, gall bladder, and pancreas is also seen in conjunction with the motor activity. These secretions probably aid in the cleansing activity of the MMC and assist in preventing a buildup of bacterial populations in the small intestine. It is during the fasting state that the MMC is put into action. For many, the term fasting implies skipping meals and enduring long periods of abstinence from food. In this case the specific periodic migrating contraction pattern we are referring to takes place when significant time occurs between meals. The MMC is interrupted by eating. For example, you ate a lovely breakfast. The food spent its time in the stomach and intestine and is making its way down the canal. ...
The aim of the present study was to characterize the mechanoenergetic alterations in a rat model of LVH undergoing pressure unloading therapy using LV P-V analysis method. According to our best knowledge, this is the first study demonstrating that the regression of LVH by pressure unloading leads not only to reversed myocardial contractility augmentation and restored diastolic function, but also to maintained cardiac mechanoenergetics.. According to Laplaces law, when the pathological stimulus of sustained pressure overload emerges, the myocardial wall thickness increases to normalize wall tension (18). This maladaptive response reaction, also known LVH, is characterized by increased expression of sarcomeric proteins with subsequent enlargement of the cardiomyocytes, ECM remodeling (10), and decreased capillary density (39). The reversibility of these alterations has been already proven by numerous previous works, since they demonstrated that the regression of preestablished pathological ...
You must be wondering how all of this applies to your fat loss program. Well, let me break it down for you - with enhanced signaling strength & motor pathways, your body is going to be able to perform movement with less effort, thereby allowing the Premotor Area of your brain to start working harder. The Premotor Area is your movement planning center. By properly learning to activate your movement planning center, you can increase contractile strength by up to 30%. Pretty crazy, huh ...
The cardiac muscle possesses automaticity and contract spontaneously. A myogenic heart is capable of generating a cardiac contraction independent of nervous input. ...
Trabeculae are supportive tissue structures in the body. They vary in function and size based on their location in the body, but...
TY - JOUR. T1 - Direct effects of hydralazine on cardiac contractile function, haemodynamics, and myocardial energetics in isolated myocardium. AU - Rendig, Stephen V.. AU - Segel, Leigh D.. AU - Amsterdam, Ezra A. PY - 1988/1/1. Y1 - 1988/1/1. N2 - The direct cardiac effects of hydralazine were studied in isolated working rat heart, isolated cat right ventricular papillary muscle, and isolated rabbit right atrium. The haemodynamics, myocardial energetics, and contractility of isolated hearts were measured at hydralazine concentrations of 0.01, 0.1, 0.5, 1.0, 10 and 100 μmol·litre-1. Coronary flow was significantly increased (≥21%, p,0.01) in paced (325 beats·min-1) rat hearts at ≥0.5 μmol·litre-1 hydralazine and in spontaneously beating hearts (≥37%; p,0.05) at ≥1.0 μmol·litre-1 hydralazine. The increases in coronary flow occurred without significant increases in heart rate, contractility (dP/dtmax), or coronary perfusion pressure. Myocardial oxygen consumption was not ...
TY - JOUR. T1 - Mechanochemotransduction during cardiomyocyte contraction is mediated by localized nitric oxide signaling. AU - Jian, Zhong. AU - Han, Huilan. AU - Zhang, Tieqiao. AU - Puglisi, Jose. AU - Izu, Leighton T. AU - Shaw, John A.. AU - Onofiok, Ekama. AU - Erickson, Jeffery R.. AU - Chen, Yi-Je. AU - Horvath, Balazs. AU - Shimkunas, Rafael. AU - Xiao, Wenwu. AU - Li, Yuanpei. AU - Pan, Tingrui. AU - Chan, James W. AU - Banyasz, Tamas. AU - Tardiff, Jil C.. AU - Chiamvimonvat, Nipavan. AU - Bers, Donald M. AU - Lam, Kit. AU - Chen-Izu, Ye. PY - 2014/3/18. Y1 - 2014/3/18. N2 - Cardiomyocytes contract against a mechanical load during each heartbeat, and excessive mechanical stress leads to heart diseases. Using a cell-in-gel system that imposes an afterload during cardiomyocyte contraction, we found that nitric oxide synthase (NOS) was involved in transducing mechanical load to alter Ca2+ dynamics. In mouse ventricular myocytes, afterload increased the systolic Ca2+ transient, which ...
TY - CHAP. T1 - Negative inotropic influence of hyperosmotic solutions on cardiac muscle. AU - Wildenthal, K.. AU - Adcock, R. C.. AU - Crie, J. S.. AU - Templeton, G. H.. AU - Willerson, J. T.. PY - 1975. Y1 - 1975. N2 - In cardiac muscle, moderate degrees of hyperosmolality of the type encountered physiologically or clinically (i.e., less than 200 mosM above control) characteristically exert a positive inotropic effect, which presumably is mediated by increased Ca 2+ availability for binding to troponin. In contrast, skeletal muscle displays significant contractile depression on exposure to hyperosmotic solutions, even at mild degrees of hypertonicity. To determine whether a similar potential for hyperosmolarity induced depression also exists in cardiac muscle, right ventricular papillary muscles from cats were exposed to hypertonic solutions of mannitol or sucrose under circumstances in which positive inotropic effects were precluded by prior exposure to a bathing solution of 4.0 mM Ca 2+ and ...
TY - JOUR. T1 - Pathophysiology and Pathogenesis of Contractile Failure in Stunned Myocardium. AU - Kusuoka, Hideo. AU - Kitakaze, Masafumi. AU - Koretsune, Yukihiro. AU - Inoue, Michitoshi. AU - Marban, Eduardo. N1 - Copyright: Copyright 2016 Elsevier B.V., All rights reserved.. PY - 1991/9. Y1 - 1991/9. N2 - To investigate excitation-contraction coupling in stunned myocardium, intracellular free calcium concentration ([Ca2+]i) was measured before and after ischemia in perfused hearts using gated 19F NMR and the Ca2+ indicator 5F-BAPTA. Maximal Ca2+-activated force was also measured in parallel experiments. Stunned myocardium was created by reperfusion after 15 min global ischemia at 37°C in isolated ferret hearts. In stunned myocardium, peak [Ca2+]i was paradoxically higher than that in control, but maximal Ca2+-activated pressure was lower in stunned hearts. These results indicate that contractile failure in stunned myocardium is due to a decrease in the myofilament sensitivity to Ca2+ as ...
Many of cTnT mutations linked to cardiomyopathies fall the TNT1 domain/N terminal tail region of unresolved high definition structure. This region (∼94-170) of cTnT is critical to Tm binding and contraction regulation. Here, the impact of the E163R mutation in cTnT-TNT1 on contractile function and tension cost was investigated using intact and skinned preparations from WT and transgenic mouse hearts. Methods: Left and right ventricular trabeculae were dissected from non-transgenic wild type (WT) and heterozygous (E163R or R92Q) mouse hearts and mounted isometrically to record twitch tension or, when skinned, Ca2+ activated force. Myofibrillar ATPase activity was measured by fluorimetric enzyme coupled assay (de Tombe and Stienen, 1995). In this thesis we aimed to assess the primary alterations of the contractile function and of tension cost caused by E163R cTnT-TNT1domain mutation, using skinned preparations or single myofibrils from WT and transgenic mouse hearts. Than we aimed to ...
The present work addressed the determination and visualization of the direction and extent of polymerization shrinkage in the light-initiated composite. Hypotheses about the light-cured composite contraction patterns are controversial. With high resolution µCT images, the displacement vector fields are examined and calculated two-dimensionally via an elastic registration algorithm using vector-spline regularization and three-dimensionally with a local rigid registration (block matching) following images segmentation (corresponding traceable fillers in composite). It appears that the light-initiated resin composites do not always shrink toward the light source. Two major contraction patterns were observed: either shrink toward the top-surface (free surface), or toward one side of the cavity wall, in which the bonding was stronger or remained intact. With the proposed methods, it is possible to describe the contraction patterns in great detail. We could demonstrate that the bonding quality to the ...
CHAPTER II: CARDIAC MECHANICS Asst. Prof. Dr. Emre Hamurtekin EMU Faculty of Pharmacy 1. 2. 3. 4. CARDIAC CYCLE CARDIAC OUTPUT DETERMINANTS of CARDIAC OUTPUT CARDIAC WORK encyclopedia.lubopitko-bg.com medical-dictionary.thefreedictionary.com • Cardiac cycle can be divided into seven phases: 1. Atrial systole 2. Isovolumic ventricular contraction 3. Rapid ventricular ejection 4. Reduced ventricular ejection 5. Isovolumic ventricular relaxation 6. Rapid ventricular filling 7. Reduced ventricular filling • Atrial systole is initiated by …………………... atrial excitation • Atrial systole follows the crest of P wave on the ECG. • Atrial contraction forces a small additional blood into the venticular chamber (atrial kick). • Ventricular systole begins with isovolumic ventricular contraction. • In isovolumic ventricular contraction, when intraventricular pressure rises, mitral valve closes. • In isovolumic ventricular contraction, aortic valve is still held closed by higher ...
Advancements in cardiovascular magnetic resonance (CMR) have made it possible to accurately assess not only standard clinical metrics such as ejection fraction (EF) and ventricular volumes, but also advanced measures of cardiac mechanics such as strain and torsion [1]-[3]. These measures of cardiac mechanics demonstrate a higher prognostic value when combined with both clinical risk factors and more traditional metrics such as ejection fraction [4]. Cine displacement encoding with stimulated echoes (DENSE) is an advanced CMR technique for measuring cardiac mechanics which encodes the displacement of the myocardium into the phase of the MR signal [5]. DENSE data can be used to reproducibly quantify cardiac mechanics, ventricular volumes, and ejection fraction [6]-[8]. Recent work has demonstrated the clinical utility of DENSE, specifically for predicting response to cardiac resynchronization therapy [9]. Despite its apparent clinical utility, DENSE has yet to see widespread adoption in clinical ...
These results demonstrate that regional left ventricular contraction can be quantitatively assessed by the myocardial velocity gradient derived from two-dimensional tissue Doppler imaging. We suggest that myocardial velocity gradient has potential for the quantitative assessment of regional left ven …
The Frank-Starling law of the heart (also known as Starling's law and the Frank-Starling mechanism) represents the relationship between stroke volume and end diastolic volume . The law states that the stroke volume of the heart increases in response to an increase in the volume of blood in the ventricles , before contraction (the end diastolic volume), when all other factors remain constant. As a larger volume of blood flows into the ventricle, the blood stretches the cardiac muscle fibers, leading to an increase in the force of contraction. The Frank-Starling mechanism allows the cardiac output to be synchronized with the venous return, arterial blood supply and humoral length, without depending upon external regulation to make alterations. The physiological importance of the mechanism lies mainly in maintaining left and right ventricular output equality. Physiology The Frank-Starling mechanism occurs as the result of the length-tension relationship observed in skeletal muscles . As a muscle
The apelin peptide is described as one of the most potent inotropic agents, produced endogenously in a wide range of cells, including cardiomyocytes. Despite positive effects on cardiac contractility in multicellular preparations, as well as indications of cardio-protective actions in several diseases, its effects and mechanisms of action at the cellular level are incompletely understood. Here, we report apelin effects on dynamic mechanical characteristics of single ventricular cardiomyocytes, isolated from mouse models (control, apelin-deficient [Apelin-KO], apelin-receptor KO mouse [APJ-KO]), and rat. Dynamic changes in maximal velocity of cell shortening and relaxation were monitored. In addition, more traditional indicators of inotropic effects, such as maximum shortening (in mechanically unloaded cells) or peak force development (in auxotonic contracting cells, preloaded using the carbon fibre technique) were studied. The key finding is that, using Apelin-KO cardiomyocytes exposed to different
Results: CHU significantly increased body mass (P , 0.001) compared with age-matched control rats but was without effect on relative cardiac mass. For incremental increases in left ventricular balloon volume, diastolic pressure was preserved. However, systolic pressure was significantly greater following CHU for balloon volume = 50 μl (P , 0.01) and up to 200 μl (P , 0.05). For higher balloon volumes systolic pressure was not significantly different from control. Developed pressures were correspondingly increased relative to controls for balloon volumes up to 250 μl (P , 0.05).Left ventricular free wall capillary density was significantly decreased in both epicardium (18%; P ,0.05) and endocardium (11%; P , 0.05) despite preserved coronary flow. Western blot analysis revealed no change to the expression of SERCA2a or nNOS but immuno-detectable eNOS protein was significantly decreased (P , 0.001) in cardiac tissue following chronic hypoxia in utero ...
TY - JOUR. T1 - Experimentally Increasing Titin Compliance in a Novel Mouse Model Attenuates the Frank-Starling Mechanism But Has a Beneficial Effect on Diastole. AU - Methawasin, M.. AU - Hutchinson, K.R.. AU - Lee, E.J.. AU - Smith, J.E.. AU - Saripalli, C.. AU - Hidalgo, C.G.. AU - Ottenheijm, C.A.C.. AU - Granzier, H.. PY - 2014. Y1 - 2014. U2 - 10.1161/CIRCULATIONAHA.113.005610. DO - 10.1161/CIRCULATIONAHA.113.005610. M3 - Article. C2 - 24599837. VL - 129. SP - 1924. EP - 1936. JO - Circulation. JF - Circulation. SN - 0009-7322. IS - 19. ER - ...
The heart - a muscle working without exhaustion and breaks. Our organism, however, has its own ways of dealing with that. One of them is the so-called Frank-Starling mechanism.
How Digoxin (lanoxin) works: INCREASES CONTRACTILITY OF THE HEART: TECH Term, it creates a POSITIVE INOTROPIC EFFECT. The Positive INOTROPIC Effect occur secondary to the inhibition of of the sodium potassium adenosine triphosphate pump. When the actions Read More …. ...
BACKGROUND: Estimating contractility of the left ventricle with noninvasive techniques is an important yet elusive goal. Positive inotropic interventions are mirrored by smaller end-systolic volumes and higher end-systolic pressures. An increased heart rate progressively increases the force of ventricular contraction (Bowditch treppe or staircase phenomenon). AIM: To assess the feasibility of a noninvasive estimation of force-frequency relation (FFR) during pacing stress in the echo lab in patients with permanent pacemaker (PM). METHODS: Transthoracic stress pacing echocardiography was performed in 26 patients with a permanent pacemaker (age 69+/-11 years; 21 men, 5 women). Seven patients had normal function at baseline and during stress (normals); eight had angiographically assessed coronary artery disease (three with and five without induced ischemia with stress echo); eleven patients had dilated cardiomyopathy (DC). To build the FFR, the force was determined at different steps as the ratio ...
2015 The Authors. Victims of chlorine (Cl2) inhalation that die demonstrate significant cardiac pathology. However, a gap exists in the understanding of Cl2-induced cardiac dysfunction. This study was performed to characterize cardiac dysfunction occurring after Cl2 exposure in rats at concentrations mimicking accidental human exposures (in the range of 500 or 600 ppm for 30 min). Inhalation of 500 ppm Cl2 for 30 min resulted in increased lactate in the coronary sinus of the rats suggesting an increase in anaerobic metabolism by the heart. There was also an attenuation of myocardial contractile force in an ex vivo (Langendorff technique) retrograde perfused heart preparation. After 20 h of return to room air, Cl2 exposure at 500 ppm was associated with a reduction in systolic and diastolic blood pressure as well echocardiographic/Doppler evidence of significant left ventricular systolic and diastolic dysfunction. Cl2 exposure at 600 ppm (30 min) was associated with biventricular failure ...
The isolated, perfused heart is known to exhibit a linear relation between aortic pressure, coronary flow rate, oxygen consumption and contractile function (rate-pressure product) over a wide range of aortic pressures. Our study sought to determine whether the cytosolic phosphorylation potential [( ATP]/[ADP][Pi]) is the link between mitochondrial respiration and contractile function in this preparation. 31P NMR spectroscopy was used to measure phosphate metabolite levels in isovolumic rat hearts during graded perfusion from 1.6 to 12.8 ml/min/g. It was found that an increase in contractile function paralleled the increase in flow rate, but that marked changes in creatine phosphate, inorganic phosphate and hydrogen ion concentration occurred only at lower flow rates. The cytosolic phosphorylation potential showed a high, positive correlation with contractile function at flow rates below 7.2 ml/min/g, which suggested that mitochondrial respiration was oxygen-limited and that the heart was ischemic. Thus,
in Journal of Cardiovascular Pharmacology (2005), 45(2), 144-152. This study investigated the effects of dobutamine on left ventriculoarterial (VA) coupling and mechanical efficiency in acutely ischemic pigs. Experiments were performed in 12 pigs in which vascular ... [more ▼]. This study investigated the effects of dobutamine on left ventriculoarterial (VA) coupling and mechanical efficiency in acutely ischemic pigs. Experiments were performed in 12 pigs in which vascular properties, including peripheral resistance (R-2), compliance (C), and arterial elastance (E-a), were estimated with a windkessel model, and left ventricular (LV) function by the slope (E-es) of the end-systolic pressure-volume relationship (ESPVR) and stroke work (SW). VA coupling was defined as E-es/E-a, and mechanical efficiency as SW/pressure-volume area (PVA). In all animals, the left anterior descending coronary artery was ligated after basal measures. The animals were then randomly divided into 2 groups: group CTRL (n ...
An ethyl acetate soluble fraction of an ethanol extract of the breadfruit leaf has been shown to have cardiodepressive properties consistent with the folklore use of the leaves of this plant as an antihypertensive agent. The cardiodepressive effect could be due to peripheral vasodilation or a negative inotropic effect on the ventricular myocardium. ...
ABSTRACT: Ventricular pressure-volume area (PVA) is a specific area in the pressure-volume diagram, which represents the total mechanical energy generated by each contraction, consisting of stroke work and mechanical potential energy at end-systole. Animal experiments have shown that PVA is correlated linearly with the ventricular oxygen consumption (Vo2) per beat under a variety of loading conditions in a stable contractile state. The slope of the Vo2-PVA line has been shown to remain constant in different contractile states, implying a constant stoichiometry between Vo2 and PVA. As a first step to understand the nature of this Vo2-PVA relation, we devised a new crossbridge (CB) model to theoretically relate PVA with the total enthalpy change associated with the ATP hydrolysis for all CB cycles. One of the most important assumptions on which this model analysis depended was that the time-varying elasticity model could simulate the instantaneous pressure-volume relation. The result of this ...
MyoKardia is a clinical stage biopharmaceutical company pioneering a precision medicine approach to discover, develop and commercialize targeted therapies for the treatment of serious and rare cardiovascular diseases. MyoKardias initial focus is on the treatment of heritable cardiomyopathies, a group of rare, genetically-driven forms of heart failure that result from biomechanical defects in cardiac muscle contraction. MyoKardia has used its precision medicine platform to generate a pipeline of therapeutic programs for the chronic treatment of the two most prevalent forms of heritable cardiomyopathy-hypertrophic cardiomyopathy, or HCM, and dilated cardiomyopathy, or DCM. MyoKardias most advanced product candidate, MYK-461, is an oral small molecule designed to reduce excessive cardiac muscle contractility leading to HCM and has been evaluated in three Phase 1 clinical trials. MyoKardia is currently studying MYK-461 in the Phase 2 PIONEER-HCM trial in symptomatic, obstructive HCM (oHCM), a ...
MyoKardia is a clinical stage biopharmaceutical company pioneering a precision medicine approach to discover, develop and commercialize targeted therapies for the treatment of serious and rare cardiovascular diseases. MyoKardias initial focus is on the treatment of heritable cardiomyopathies, a group of rare, genetically-driven forms of heart failure that result from biomechanical defects in cardiac muscle contraction. MyoKardia has used its precision medicine platform to generate a pipeline of therapeutic programs for the chronic treatment of the two most prevalent forms of heritable cardiomyopathy-hypertrophic cardiomyopathy, or HCM, and dilated cardiomyopathy, or DCM. MyoKardias most advanced product candidate, MYK-461, is an oral small molecule designed to reduce excessive cardiac muscle contractility leading to HCM and has been evaluated in three Phase 1 clinical trials. MyoKardia is currently studying MYK-461 in the Phase 2 PIONEER-HCM trial in symptomatic, obstructive HCM (oHCM), a ...
Liguzinediol (LZDO) ester prodrugs 3-5 were synthesized and evaluated in vitro and in vivo for their potential use in prolonging the half-life of the parent drug LZDO (1a) in vivo. Prodrugs 3-5 were found to display a potent positive inotropic effect on the myocardium, without the risk of arrhythmia. Prodrugs 3-5 rapidly underwent enzymatic hydrolysis to release the parent compound LZDO in 1-3 h in rat liver microsomes and rat plasma. The half-life of the parent compound was prolonged after intragastric administration of prodrug 3, which was found to be a superior prodrug candidate for increasing myocardial contractility.
Small heat shock protein which functions as a molecular chaperone probably maintaining denatured proteins in a folding-competent state. Seems to have versatile functions in various biological processes. Plays a role in regulating muscle function such as smooth muscle vasorelaxation and cardiac myocyte contractility. May regulate myocardial angiogenesis implicating KDR. Overexpression mediates cardioprotection and angiogenesis after induced damage. Stabilizes monomeric YWHAZ thereby supporting YWHAZ chaperone-like activity.
In this study, we demonstrate that sodium deprivation in rats causes alterations in cardiac βAR affinity responsiveness assessed by adenylyl cyclase activity. Our data indicate that a primary mechanism is the reduction of the percentage of βARs in the high affinity conformation caused by the increased expression and activity of cardiac βARK1. Interestingly, atenolol treatment prevented the rise in βARK1 levels in the heart and improved βAR signaling.. The pivotal role of βARK1 in cardiac βAR signaling and function was first shown in transgenic mice with cardiac overexpression of this GRK.24 In that study it was shown for the first time that this regulator of βAR signaling was able (in absence of other alterations of the excitation-contractile machinery of the heart) to dampen the cardiac contractile response to βAR stimulation.24 After this initial study, many observational studies have associated increased cardiac βARK1 levels to animal and human models of cardiac dysfunction.5-10 ...
global entire cell i transients in early cardiac cells derived from mouse ESC had been reported to be the result of spontaneous Ca2 release from intracellular Ca2 outlets devoid of the triggering of membrane Checkpoint kinase inhibitor Ca2 currents. The mechanism underlying E C coupling in hESC CMs is somewhat controversial. When some reviews suggested the absence of the functional SR Ca2 retail outlet in hESC CMs and postulated that fundamentally all the i transients in these cells were a consequence of transsarcolemmal Ca2 influx via membranal Ca2 channels, others have argued to get a a lot more mature like CICR mechanism. The latter scientific studies reported the presence of a practical caffeine responsive and ryanodine delicate SR Ca2 keep in not less than a subset if not all, of the cells tested, within a related method to the hiPSCCMs studied in the existing review.. Our outcomes assistance the contribution of both the transsarcolemmal Ca2 Chromoblastomycosis influx and intracellular Ca2 ...
doppler tissue echocardiography (DTE) has been widely used in clinical practice to provide noninvasive information on regional left ventricular (LV) systolic and diastolic function (3, 16, 20, 21, 25, 27) and on filling pressures (8, 12, 14, 15, 17) and to measure mechanical synchronicity (30). By using this imaging modality, regional longitudinal myocardial tissue contraction and relaxation velocities, as well as one-dimensional strain (ε) and strain rate (SR), can be quantified and used as indexes of regional function.. The mitral annulus motion represents changes in longitudinal LV long-axis dimension, which could reflect LV volume changes. In the clinical evaluation of ventricular function, assessment of the rate of change in LV volume, rather than the absolute change, is desirable, since it is assumed that an abnormality reflected in the long-axis dimension could be evident earlier than the clinical manifestation of global LV abnormality. DTE provides this information, as it has the ...
GTPases of the Rho family regulate actinomyosin-based contraction in non-muscle cells. Activation of Rho increases contractility, leading to cell rounding and neurite retraction in neuronal cell lines. Activation of Rac promotes cell spreading and interferes with Rho-mediated cell rounding. Activation of Rac may antagonize Rho by regulating phosphorylation of the myosin-II heavy chain. Stimulation of PC12 cells or N1E-115 neuroblastoma cells with bradykinin induces phosphorylation of threonine residues in the myosin-II heavy chain; this phosphorylation is Ca2+ dependent and regulated by Rac. Both bradykinin-mediated and constitutive activation of Rac promote cell spreading, accompanied by a loss of cortical myosin II. These results identify the myosin-II heavy chain as a new target of Rac-regulated kinase pathways, and implicate Rac as a Rho antagonist during myosin-II-dependent cell-shape changes (van Leeuwen, 1999). The molecular events responsible for Rac-mediated cytoskeletal changes are not ...
The ß-adrenergic receptors are linked to G proteins. The ß-receptor has three known subtypes. Beta-1 receptors primarily regulate myocardial tissue and affect the rate of contraction via impulse conduction. Beta-2 receptors regulate smooth muscle tone and influence vascular and bronchiolar rela...
The main contribution of integrating 4D SPIM technique with hemodynamic forces resides in the elucidation of the interplay between shear stress and Notch activation in initiating trabeculation during cardiac morphogenesis. By implementing the nongated 4D synchronization algorithm with SPIM, we have unraveled the trabecular network in association with ventricular contractile function. While the development of trabeculation is conserved between the zebrafish and chick, mouse, and human embryos (3, 23, 37-39), there are numerous layers of cardiomyocytes in mice (23), and there is a thin layer of cardiomyocytes for trabeculation in zebrafish embryos. For this reason, 4D SPIM imaging enables uniform illumination to uncover shear stress-induced endocardial Notch signaling to form a trabecular network for contractile function with high axial, spatial, and temporal resolution. We demonstrated that (a) gata1a MO decreased hematopoiesis to reduce shear stress, (b) tnnt2a MO inhibited ventricular ...
BACKGROUND: Response of the human heart to exercise has been studied extensively, but little information is available on the effects of exhaustive exercise on cardiac performance. OBJECTIVES: The aim of this study was to evaluate the effect of severe
Ca2+ channel β-subunit interactions with pore-forming α-subunits are long-thought to be obligatory for channel trafficking to the cell surface and for tuning of basal biophysical properties in many tissues. Unexpectedly, we demonstrate that transgenic expression of mutant α1C subunits lacking capacity to bind CaVβ can traffic to the sarcolemma in adult cardiomyocytes in vivo and sustain normal excitation-contraction coupling. However, these β-less Ca2+ channels cannot be stimulated by β-adrenergic pathway agonists, and thus adrenergic augmentation of contractility is markedly impaired in isolated cardiomyocytes and in hearts. Similarly, viral-mediated expression of a β-subunit-sequestering peptide sharply curtailed β-adrenergic stimulation of WT Ca2+ channels, identifying an approach to specifically modulate β-adrenergic regulation of cardiac contractility. Our data demonstrate that β subunits are required for β-adrenergic regulation of CaV1.2 channels and positive inotropy in the ...
Genetic Counseling: using x-rays of the factors transmitted suffering to free mechanisms, in benzothiazepine that they may characterize an MVO2 heart on previous or entire leads. Genetic Engineering: been work of the Faculty decompensation of a pacing transplant by functional complexes as pumping the book, surrounding independent phosphate by cases of a appearance, pacing various fibrates, managing lambda disorders, etc. Genetic Markers: A Therefore total myocardial contraction which can be left to have a Such gene, a heart urine, or a model pressure. capable: increasing to the stability.
一酸化窒素ドナーNOC7はラット孤立心筋モデル全虚血後の心収縮力に二相性に作用する Nitric oxide donor, NOC7, reveals biphasic effect on contractile force of isolated rat heart after global ischemia ...
Free Online Library: Ask Doctor Cory. by Childrens Playmate; Health, general Dyspepsia Care and treatment Causes of Heart Contraction Physiological aspects Heart contraction Lung cancer
An optimal interaction between the Ventricular Assist Device and assisted heart will depend on precise timing of maximal flow generated by the device in relation to the ejection phase of the assisted heart. Such precise timing can be derived from the pressure-volume plane. The logic holds that a heart treated with a pump should be analyzed as a pump. ...
The researchers inserted human genes into insect cells to make heart muscle proteins for study. Dawsons lab is one of the few in the world able to do this work.. They then mapped where on the abnormalities occurred and their effects. Three were in spots that resulted in problems with heart contractions; three others were in locations that affected stability and efficiency.. Dawson hopes their work will help in developing more targeted treatments ...
Can normalize blood pressure and myocardial contraction. It has been shown to enhance the efficiency of oxidative ...
Forceful myocardial contraction, in turn mainly caused by ventricular fibrillation or electrical injury. Additional signs ... Intercalated discs support synchronized contraction of cardiac tissue. They occur at the Z line of the sarcomere and can be ... indicating forceful myocardial contraction are: Alternating bundles of hypercontracted myocytes with hyperdistended ones. ... Desmosomes stop separation during contraction by binding filaments, joining the cells together. Desmosomes are also known as ...
Goldberg SJ, Comerci GD, Feldman L (January 1988). "Cardiac output and regional myocardial contraction in anorexia nervosa". ... myocardial fibrosis, and pericardial effusion. Abnormalities in conduction and repolarization of the heart that can result from ...
The combination of increased and prolonged cross-bridge formation prolongs myocardial contraction. Thus, the overall clinical ... There is a slight decrease in heart rate while myocardial oxygen consumption is unaffected. The increased cardiac output is ... Current inotropic therapies work by increasing the force of cardiac contraction, such as through calcium conduction or ... This enhances effective myosin cross-bridge formation and duration, while the velocity of contraction remains the same. ...
Because of this, blood flow in the subendocardium stops during ventricular contraction. As a result, most myocardial perfusion ... Chronic moderate ischemia causes contraction of the heart to weaken, known as myocardial hibernation.[citation needed] In ... If the papillary muscles are not functioning properly, the mitral valve may leak during contraction of the left ventricle. This ... The clinical significance of this is that a myocardial infarction involving the PDA is more likely to cause mitral ...
"Myocardial contraction is 5-fold more economical in ventricular than in atrial human tissue". Cardiovascular Research. 65 (1): ... It is the major protein comprising the cardiac muscle thick filament, and functions in cardiac muscle contraction. Mutations in ... "Myosin heavy chain composition and the economy of contraction in healthy and diseased human myocardium". Journal of Muscle ...
This estimation of myocardial oxygen consumption (MVO2) is used to study the coupling of mechanical work and the energy ... An increase in contractility is manifested as an increase in dP/dtmax during isovolumic contraction. However, dP/dtmax is also ... Myocardial infarction or cardiomyopathy causes damage to the myocardium, which impairs the heart's ability to eject blood and, ... During heart failure, myocardial contractility is reduced, which decreases the slope of the PRSW relationship. Recent studies ...
... is a determinant of stroke volume (in addition to preload, and strength of myocardial contraction). Following ... Afterload is the pressure that the heart must work against to eject blood during systole (ventricular contraction). Afterload ...
Tsoporis JN, Marks A, Zimmer DB, McMahon C, Parker TG (January 2003). "The myocardial protein S100A1 plays a role in the ... Kettlewell S, Most P, Currie S, Koch WJ, Smith GL (December 2005). "S100A1 increases the gain of excitation-contraction ... S100A1 has shown to be a regulator of myocardial contractility. S100A1 overexpression via adenoviral gene transfer in adult ... S100A1 has shown promise as an early diagnostic biomarker for acute myocardial ischemia, presenting with a distinct timecourse ...
Micrograph showing karyolysis and contraction band necrosis in an individual that had a myocardial infarction (heart attack). ... Micrograph showing karyolysis and contraction band necrosis (left of image) and ischemic (nucleated) cardiac myocytes (right of ... image) in an individual that had a myocardial infarction. Apoptosis Necrosis Pyknosis Karyorrhexis Cotran; Kumar, Collins (1998 ...
When the heart is damaged by a myocardial infarction a portion of muscle is permanently lost. The heart has a limited innate ... This decreases the preload and results in a left-shift and loss of the normal isovolumic contraction line. Under conditions of ... Clinical research indicates that as the size of the myocardial scar increases, so does the likelihood of the patient to develop ... Heart failure after myocardial infarction: clinical implications and treatment. Clinical Cardiology. 2011;34(7):410-414. D. S. ...
In myocardial infarction, ischemia of the myocardium can extend to the endocardium, disrupting the inner lining of the heart (" ... The endocardium underlies the much more voluminous myocardium, the muscular tissue responsible for the contraction of the heart ... The endocardium, which is primarily made up of endothelial cells, controls myocardial function. This modulating role is ... Thus, the cardiac endothelium (both the endocardial endothelium and the endothelium of the myocardial capillaries) controls the ...
Ouabain Digoxin Myocardial infarction Toxicity Detoxification Muscle contraction Cardiac glycosides 新药研发咨询中心. "k-Strophanthidin ... He also found out that the use of cardiac stimulant might alleviate myocardial depression in the presence of shock (first ... Iacono G, Vassalle M (April 1990). "On the mechanism of the different sensitivity of Purkinje and myocardial fibers to ...
... as well as myocardial mass. Tagging sequences excite a grid pattern that deforms with cardiac contraction allowing strain to be ... T1-weighted sequences are used to visualize anatomy and detect the presence of intra-myocardial fat. T1 mapping has also been ... Myocardial viability can be assessed by the degree of transmural enhancement. Cardiomyopathic, inflammatory and infiltrative ... A positive result is evident from an inducible myocardial perfusion defect. Cost and availability mean that its use is often ...
Angina is chest pain that results from episodes of transient myocardial ischemia. This can be caused by diseases such as ... There are multiple mechanisms causing the increased smooth muscle contraction involved in coronary vasospasm, including ... "Cyclic GMP-dependent protein kinase signaling pathway inhibits RhoA-induced Ca2+ sensitization of contraction in vascular ...
He continues to study aspects of myocardial contraction and coronary blood flow in collaboration with investigators at other ...
The ventricular myocardial band model supports the existence of an active muscular contraction that creates suction (creation ... Thus, it is the contraction of the ascending segment of the myocardial band that paradoxically increases the ventricular volume ... the former is produced by the active contraction of the cardiac musculature contraction while the second by its relaxation. ... By folding, the myocardial band crates a septum that separates two ventricular chambers of the heart close to the time of birth ...
"2014 ESC/EACTS Guidelines on myocardial revascularization: the Task Force on Myocardial Revascularization of the European ... During contraction of a cardiac muscle cell, the long protein myofilaments oriented along the length of the cell slide over ... The primary function of both muscle types is to contract, and in both cases, a contraction begins with a characteristic flow of ... The myocardium found in the ventricles is thick to allow forceful contractions, while the myocardium in the atria is much ...
If heart failure ensues after a myocardial infarction due to scarring and aneurysm formation, reconstructive surgery may be an ... Mesh-like constraint devices such as the Acorn CorCap aim to improve contraction efficacy and prevent further remodeling. ... These aneurysms bulge with every contraction, making it inefficient. Cooley and coworkers reported the first surgical treatment ... Cooley DA, Collins HA, Morris GC, Chapman DW (May 1958). "Ventricular aneurysm after myocardial infarction; surgical excision ...
This signal stimulates contraction first of the right and left atrium, and then the right and left ventricles. This process ... Like a neuron, a given myocardial cell has a negative membrane potential when at rest. Stimulation above a threshold value ... Contraction that squeezes blood towards the exit is more efficient than a simple squeeze from all directions. Although the ... Sustained contraction of the heart without relaxation would be fatal, and this is prevented by a temporary inactivation of ...
This prevents the atria from undergoing coordinated contraction, instead resulting in small fibrillations of the heart muscle. ... disorganized electrical impulses in the atria resulting in depolarization of only a small group of myocardial cells. ... and the refractory period in canine myocardial infarction". Journal of Cardiovascular Pharmacology. 19 (3): 417-24. doi:10.1097 ...
The initial remodeling phase after a myocardial infarction results in repair of the necrotic area and myocardial scarring that ... Eventually, diastolic function, or the heart's ability to relax between contractions may become impaired, further causing ... A common scenario for remodeling is after myocardial infarction. There is myocardial necrosis (cell death) and disproportionate ... Clinical trials have shown that ACE inhibitor therapy after myocardial infarction leads to improved myocardial performance, ...
Polysubstitution on carbon 2 and 6 makes the compound inactive but when the substitution is on carbon 3 and 5 there's some ... The treatment with β-blockers reduces the incidence of sudden heart failure when the patient has already had a myocardial ... A β-blocker therapy is also useful in myocardial infarction, independent to heart failure. The therapy has been very helpful ... The blocking of β2 receptor promotes vascular smooth muscle contraction, which results in increase of peripheral resistance. ...
The short- and long-term use of this therapy enhances the strength of ventricular contraction and therefore the heart's pumping ... Based on animal testing and experiments on human myocardial tissue obtained by biopsies, essential parts of the mechanism of ... In this phase of the cardiac cycle, electrical signals cannot trigger new cardiac muscle contractions, hence this type of ... Rather, the aim is to enhance the heart's natural contraction (the native cardiac contractility) sustainably over long periods ...
The term inotropic state is most commonly used in reference to various drugs that affect the strength of contraction of heart ... myocardial infarction) can decrease it. Both positive and negative inotropes are used in the management of various ... An inotrope is an agent that alters the force or energy of muscular contractions. Negatively inotropic agents weaken the force ... of muscular contractions. Positively inotropic agents increase the strength of muscular contraction. ...
This enlargement of the cleft is caused by contraction of capillary endothelial cells, often by substances such as histamine ... The intercellular cleft between endocardial endotheliocytes is 3 to 5 times deeper than the clefts between myocardial capillary ...
Overall, adenosine decreases the heart's rate and force of contraction, which increases blood supply to the cardiac muscle. ... It is also used in the treatment of heart block due to acute inferior myocardial infarction. Aminophylline has shown some ... Adenosine is an endogenous extracellular messenger that can regulate myocardial oxygen needs. It acts through cellular surface ...
The atrium walls tend to be thinner than the ventricle walls, due to the intense ventricular contraction used to pump ... Much like a mammalian heart, the avian heart is composed of endocardial, myocardial and epicardial layers. ... The arteries are composed of thick elastic muscles to withstand the pressure of the ventricular contractions, and become more ... of each side are separated by atrioventricular valves which prevent back flow from one chamber to the next during contraction. ...
The rhythm of contraction is controlled by the pace maker cells which have a lower threshold for depolarization. The wave of ... Much like a mammalian heart, the avian heart is composed of endocardial, myocardial and epicardial layers. The atrium walls ... of each side are separated by atrioventricular valves which prevent back flow from one chamber to the next during contraction. ... tend to be thinner than the ventricle walls, due to the intense ventricular contraction used to pump oxygenated blood ...
Weirich WL, Gott VL, Lillehei CW (1957). "The treatment of complete heart block by the combined use of a myocardial electrode ... At the end of the tracing, distortion results from muscle contractions due to a (short) hypoxic seizure. Because decreased ... Thus, timing between the atrial and ventricular contractions, as well as between the septal and lateral walls of the left ... Although these dual-chamber models are usually more expensive, timing the contractions of the atria to precede that of the ...
Myocardial bridge. Active ischemia. *Angina pectoris *Prinzmetal's angina. *Stable angina. *Acute coronary syndrome *Myocardial ...
Upon view, the myocardial cells are observed to have large densely packed chromosomes within the nucleus.[69] ... It is composed of myogenic muscular tissue associated with heart contraction features. There is a double circulatory plan in ... It also contains fewer myofibrils than usual myocardial cells. The AV node connects the atrial and ventricular chambers. It ... rapid rhythmic contraction and relaxation of throat muscles, in a similar way to panting.[64] Both these behaviors allow the ...
Temporay pacing may be done for very slow heartbeats, or bradycardia, from drug overdose or myocardial infarction. A pacemaker ... When an electrical impulse begins in any part of the heart, it will spread throughout the myocardium and cause a contraction; ... The muscle cells of the heart normally function together, creating a single contraction when stimulated. Fibrillation occurs ... the various parts of the heart muscle with slightly different timing than usual and causes a poorly coordinated contraction. ...
However the serotonin and the thromboxane A2 cause more contraction of the smooth muscle cells and as a result contractions ... Ischemia in the heart due to prolonged coronary vasospasm can lead to angina, myocardial infarction and even death. ... However, aggregating platelets also stimulate thromboxane A2 and serotonin which can induce contraction of the smooth muscle ... In general, the relaxations outweighs the contractions. During atherosclerosis a dysfunctional endothelium is observed during ...
Though uncommon, potentially fatal adverse effects include stroke, myocardial infarction, GI bleeding, Stevens-Johnson syndrome ... Prostaglandin functions in the body as a messenger for contraction/relaxation of smooth muscle and modulation of inflammation. ... myocardial infarction, stroke, heart failure, coagulation disorders, renal impairment, and hepatic impairment.[8][9] ...
Much like a mammalian heart, the avian heart is composed of endocardial, myocardial and epicardial layers.[82] The atrium walls ... of each side are separated by atrioventricular valves which prevent back flow from one chamber to the next during contraction. ... tend to be thinner than the ventricle walls, due to the intense ventricular contraction used to pump oxygenated blood ... signal transduction pathway from the atrium through right and left atrioventricular bundle which communicates contraction to ...
During ventricular contraction, the wave of depolarization moves from the endocardial to the epicardial surface. ... but may also occur following a myocardial infarction. Pericarditis is usually a short-lived condition that can be successfully ...
As with the A1, the A2A receptors are believed to play a role in regulating myocardial oxygen consumption and coronary blood ... Smooth muscle contraction. *cardioprotective in cardiac ischemia. *inhibition of neutrophil degranulation. *2-(1-Hexynyl)-N- ... The A1, together with A2A receptors of endogenous adenosine play a role in regulating myocardial oxygen consumption and ... The A2A receptor is responsible for regulating myocardial blood flow by vasodilating the coronary arteries, which increases ...
Myocardial stunning. *days *Myocardial rupture. *weeks *Aneurysm of heart / Ventricular aneurysm. *Dressler syndrome ...
Secondary AF - occurs in the setting of a primary condition that may be the cause of the AF, such as acute myocardial ... In atrial fibrillation, the lack of an organized atrial contraction can result in some stagnant blood in the left atrium (LA) ... Correlation of delirium cordis with the loss of atrial contraction, as reflected in the loss of a waves in the jugular venous ... but the restoration of normal atrial contraction has not yet occurred.[114] ...
By acting on vascular smooth muscle, they reduce contraction of the arteries and cause an increase in arterial diameter, a ... Phenylalkylamine calcium channel blockers are relatively selective for myocardium, reduce myocardial oxygen demand and reverse ... Voltage-dependent calcium channels are responsible for excitation-contraction coupling of skeletal, smooth, and cardiac muscle ... Reducing the force of contraction of the myocardium is known as the negative inotropic effect of calcium channel blockers. ...
As such, it can be caused by a wide number of conditions, including myocardial infarction (in which the heart muscle is starved ... of oxygen and dies), hypertension (which increases the force of contraction needed to pump blood) and amyloidosis (in which ...
... and pumping from contraction of skeletal muscles also influence blood pressure, particularly in veins.[52] ... myocardial contractility and systemic arterial vasoconstriction to preserve blood pressure and elicits venous vasoconstriction ... adjusts the mean arterial pressure by altering both the force and speed of the heart's contractions, as well as the systemic ...
non-fatal myocardial infarction. , death. ). 1.29 (1.02-1.63). 1.32 (1.02-1.72). 1.18 (0.70-1.97). 30. 23. 6. 37. 30. 7 ... Beyond this, HRT improves heart contraction, coronary blood flow, sugar metabolism, and decreases platelet aggregation and ...
nNOS in the heart protects against cardiac arrhythmia induced by myocardial infarction. The primary receiver for NO produced by ... generation of nitric oxide through increased iNOS production may decrease tubal ciliary beats and smooth muscle contractions ... "Neuronal nitric oxide synthase protects against myocardial infarction-induced ventricular arrhythmia and mortality in mice". ...
If the heart muscle contraction is intact, the condition is known as respiratory arrest. An abrupt stop of pulmonary gas ... If frequent arrhythmias, myocardial ischemia and shock arrhythmias occur, practitioners should change delivery to endotracheal ... Respiratory arrest is also different from cardiac arrest, the failure of heart muscle contraction. If untreated, one may lead ...
In the diastolic phase, it has to relax very quickly after each contraction so as to quickly fill with the oxygenated blood ... However, both endocardial and midwall fractional shortening are dependent on myocardial wall thickness, and thereby dependent ... which is independent of myocardial wall thickness". American Journal of Physiology. Heart and Circulatory Physiology. 298 (2): ... is independent of myocardial wall thickness and represents isolated short-axis function.[21] ...
... and strength of cardiac muscle contraction. such as hypertrophy or dilatation of the main chambers. (ventricle and atrium) ... in echocardiography to improve delineation of left ventricle for visually checking contractibility of heart after a myocardial ...
Aspirin Resistance in Patients with Stable Coronary Artery Disease with and without a History of Myocardial Infarction. Annals ... decrease agonist-induced contractions of the pig isolated ureter. Urological Research. 2000-12-01, 28 (6): 376-382. ISSN 0300- ... A comparison of aspirin and anticoagulation following thrombolysis for myocardial infarction (the AFTER study): a multicentre ... Protective Effects of Aspirin against Acute Myocardial Infarction and Death in Men with Unstable Angina. New England Journal of ...
Myocardial perforation, pneumothorax and infection, all of which have an incidence of less than 1% ... a cardiac abnormality leading to delayed left ventricular contraction. LBBB causes a QRS prolongation of ,120 ms on the ... "3D fusion of LV venous anatomy on fluoroscopy venograms with epicardial surface on SPECT myocardial perfusion images for ...
This leads to increased contractility (the force of contraction) of the heart without increasing heart energy expenditure.[ ... It exerts a mechanical effect as it increases myocardial contractility; however, the duration of the contractile response is ...
Premature ventricular contraction. *Wolff-Parkinson-White syndrome. References[edit]. *^ a b c d Josephson, Mark E. (2015-08-10 ... Myocardial bridge. Active ischemia. *Angina pectoris *Prinzmetal's angina. *Stable angina. *Acute coronary syndrome *Myocardial ...
slow-twitch skeletal muscle fiber contraction. • response to hypoxia. • enucleate erythrocyte differentiation. • response to ... elevated myoglobin has low specificity for acute myocardial infarction (AMI) and thus CK-MB, cardiac Troponin, ECG, and ...
... thus preventing myocardial infarction. A small stent can be inserted at the angioplasty site to keep the vessel open after the ... there will be a certain amount of expansion/contraction. As air pressure itself is a description of the total forces against an ... but it also has to counteract the natural contraction of the balloon. Therefore, it requires more air pressure (or force) than ...
Premature ventricular contraction. References[edit]. *^ Tipton MJ, Kelleher PC, Golden FS Institute of Naval Medicine, Gosport ... Premature junctional contractions (PJCs), also called atrioventricular junctional premature complexes or junctional ... On the surface ECG, premature junctional contractions will appear as a normally shaped ventricular complex or QRS complex, not ... Retrieved from "https://en.wikipedia.org/w/index.php?title=Premature_junctional_contraction&oldid=856667478" ...
... is the speed of the heartbeat measured by the number of contractions (beats) of the heart per minute (bpm). The ... "Influence of heart rate on mortality after acute myocardial infarction". The American Journal of Cardiology. 65 (9): 547-53. ... Table 1: Major factors increasing heart rate and force of contraction[11] Factor Effect ... Hypothermia slows the rate and strength of heart contractions. This distinct slowing of the heart is one component of the ...
Here's how Pfizer did it". Fortune.. *^ a b US patent 4681893, Roth Bruce D., "Trans-6-[2-(3- or 4-carboxamido-substituted ... Myocardial infarction and stroke prophylaxis in patients with type II diabetes[23][24][25] ... Here's how Pfizer did it". Fortune. Retrieved 2011-10-26.. *. Winslow, Ron (2000-01-24). "The Birth of a Blockbuster: Lipitor's ... Secondary prevention of myocardial infarction, stroke, unstable angina,[19][20] and revascularization in people with ...
A Model of Post-myocardial Infarction Remodelling and Heart Failure, Analysis of Tubular Membrane Networks in Cardiac ... In Vivo Quantitative Assessment of Myocardial Structure, Function, Perfusion and Viability Using Cardiac Micro-computed ... Transthoracic Speckle Tracking Echocardiography for the Quantitative Assessment of Left Ventricular Myocardial Deformation, ... Assessment of Myofilament Ca2+ Sensitivity Underlying Cardiac Excitation-contraction Coupling, ...
Myocardial Contraction. Known as: contractions heart, Contraction, Myocardial, Heart--Contraction Expand. The multicellular ... Monocytes: protagonists of infarct inflammation and repair after myocardial infarction.. *M. Nahrendorf, M. Pittet, F. Swirski ... Myocardial infarction (MI) is the most frequent cause of heart failure, which is an incapacitating disease with high prevalence ... Regulation of cardiac contraction by neurotransmitters and hormones is often correlated with regulation of the L-type Ca2… ...
... the increases in isotonic contraction and in cyclic AMP, produced by 2 μg of histamine were significantly and almost completely ... Specific inhibition by burimamide of histamine effects on myocardial contraction and cyclic AMP. ... Heart-Contraction Cyclic AMP Histamine Burimamide This work was supported by grant Nr. 1301 of the Fonds zur Förderung der ... Klein, I., Levey, G. S.: Activation of myocardial adenylate cyclase by histamine in guinea-pig, cat, and human heart. J. clin. ...
Severity of contraction abnormalities after acute myocardial infarction in man: response to nitroglycerin.. K B Ramanathan, M M ... Severity of contraction abnormalities after acute myocardial infarction in man: response to nitroglycerin. ... Severity of contraction abnormalities after acute myocardial infarction in man: response to nitroglycerin. ... Severity of contraction abnormalities after acute myocardial infarction in man: response to nitroglycerin. ...
INTRODUCTION: Myocardial contraction fraction (MCF) is the ratio of left ventricular (LV) stroke volume to myocardial volume ... LV and myocardial volumes were determined from volumetric breathold-cine SSFP CMR datasets. MACE were: CV death, myocardial ... Abstract 2829: Decreased Left Ventricular Myocardial Contraction Fraction Predicts Excess Cardiovascular Morbidity and ... Abstract 2829: Decreased Left Ventricular Myocardial Contraction Fraction Predicts Excess Cardiovascular Morbidity and ...
Assessment of left ventricular long axis contraction can detect early myocardial dysfunction in asymptomatic patients with ... Assessment of left ventricular long axis contraction can detect early myocardial dysfunction in asymptomatic patients with ... and short axis contraction. However, patients in group II had reduced long axis contraction compared with group I: peak ... From the spectral traces we measured peak velocities during early filling (ETDE) and atrial contraction (ATDE). The ETDE:ATDE ...
Reversal of Isoflurane-Induced Depression of Myocardial Contraction by Nitroxyl via Myofilament Sensitization to Ca2+. Wengang ... The effects of inhalational anesthetic agents on myocardial contraction have been the focus of extensive investigations for ... Reversal of Isoflurane-Induced Depression of Myocardial Contraction by Nitroxyl via Myofilament Sensitization to Ca2+ ... all together these data strongly support our initial hypothesis that the ISO-induced negative effect on myocardial contraction ...
We suggest that myocardial velocity gradient has potential for the quantitative assessment of regional left ven … ... These results demonstrate that regional left ventricular contraction can be quantitatively assessed by the myocardial velocity ... Myocardial velocity gradient as a new indicator of regional left ventricular contraction: detection by a two-dimensional tissue ... These results demonstrate that regional left ventricular contraction can be quantitatively assessed by the myocardial velocity ...
Functional Myocardial Perfusion Abnormality Induced by Left Ventricular Asynchronous Contraction: Experimental Study Using ... Functional Myocardial Perfusion Abnormality Induced by Left Ventricular Asynchronous Contraction: Experimental Study Using ... Functional Myocardial Perfusion Abnormality Induced by Left Ventricular Asynchronous Contraction: Experimental Study Using ... The aim of this study was to clarify how myocardial perfusion is impaired by asynchronous contraction. ...
... Roscher, Roger ... CONCLUSION: Cooling to 32 degrees C significantly prolongs the myocardial action potential and the contraction duration. ... CONCLUSION: Cooling to 32 degrees C significantly prolongs the myocardial action potential and the contraction duration. ... After 45 min of equilibration at 37 degrees C or 32 degrees C, resting and action potentials, time to peak contraction and ...
Conclusion Two-dimensional myocardial acceleration mapping can show the intramural site of origin of myocardial contraction in ... Conclusion Two-dimensional myocardial acceleration mapping can show the intramural site of origin of myocardial contraction in ... Conclusion Two-dimensional myocardial acceleration mapping can show the intramural site of origin of myocardial contraction in ... Conclusion Two-dimensional myocardial acceleration mapping can show the intramural site of origin of myocardial contraction in ...
Myocardial perfusion was assessed by using myocardial contrast echocardiography (MCE) in dogs with asynchronous contraction ... Functional Myocardial Perfusion Abnormality Induced by Left Ventricular Asynchronous Contraction: Experimental Study Using ... Functional Myocardial Perfusion Abnormality Induced by Left Ventricular Asynchronous Contraction: Experimental Study Using ... Functional Myocardial Perfusion Abnormality Induced by Left Ventricular Asynchronous Contraction: Experimental Study Using ...
Cardiac contraction motion compensation in gated myocardial perfusion SPECT: A comparative study. Physica Medica. 2018 May 1;49 ... Cardiac contraction motion compensation in gated myocardial perfusion SPECT : A comparative study. In: Physica Medica. 2018 ; ... Cardiac contraction motion compensation in gated myocardial perfusion SPECT : A comparative study. / Salehi, Narges; Rahmim, ... N2 - Introduction: Cardiac contraction significantly degrades quality and quantitative accuracy of gated myocardial perfusion ...
... where more than 1 million people have acute myocardial infarctions (AMIs) each year. The advent of coronary care units and ... Myocardial infarction (MI) due to coronary artery disease is a leading cause of death in the United States, ... Premature atrial contractions. Premature atrial contractions often occur before the development of paroxysmal supraventricular ... It is devoid of myocardial elements, whereas a true aneurysm has all the elements of the original myocardial wall and a ...
Mechanisms other than myocardial ischemia may lead to the occurrence of reversible regional myocardial contraction ... Mechanisms other than myocardial ischemia may lead to the occurrence of reversible regional myocardial contraction ... Mechanisms other than myocardial ischemia may lead to the occurrence of reversible regional myocardial contraction ... Mechanisms other than myocardial ischemia may lead to the occurrence of reversible regional myocardial contraction ...
In the above example, myocardial contraction, the metabolism aspect of myocardium, and oxygen consumption are the central ... MH - *Myocardial Contraction. MH - Myocardium/*metabolism. MH - *Oxygen Consumption. MH - Surface Tension ... TI - [The effect of anti-arrhythmic drugs on myocardial function (authors transl)]. TI - Prevalence of Helicobacter pylori ...
Mild focal myocyte disarray and myocardial fibrosis. *- Focal hemorrhage of blood in the bundle of His and ventricular septum ... Contraction bands without inflammation. *- Severe focal narrowing of the atrioventricular node artery ...
To test this hypothesis, we have investigated myocardial Ca2+ handling and contractility in nNOS knockout mice (nNOS-/-) and in ... nNOS gene disruption or L-VNIO increased basal contraction both in left ventricular (LV) myocytes (steady-state cell shortening ... NOS in the proximity of an activating source of Ca2+ suggests that cardiac nNOS-derived NO may regulate contraction by exerting ... Cardiac neuronal nitric oxide synthase isoform regulates myocardial contraction and calcium handling. ...
Myocardial Contraction. Myocardial Infarction / physiopathology. Pulmonary Circulation. Shock, Cardiogenic / physiopathology*. ...
PVS premature ventricular systole (contraction). PWI posterior wall infarction. PWMI posterior wall myocardial infarction ... APC auricular premature contraction; acetylsalicylic acid, acetophenetidin, and caffeine. APE acute pulmonary edema; anterior ...
Myocardial contraction and relaxation. Role of anesthesia in depression and recovery during controlled regional ischemia. ... Myocardial contraction and relaxation. Role of anesthesia in depression and recovery during controlled regional ischemia. / ... Behrenbeck, T. ; Quasha, A. L. ; Tinker, J. H. ; Ritman, E. L. / Myocardial contraction and relaxation. Role of anesthesia in ... T1 - Myocardial contraction and relaxation. Role of anesthesia in depression and recovery during controlled regional ischemia ...
myocardial injury synonyms, myocardial injury pronunciation, myocardial injury translation, English dictionary definition of ... myocardial injury. n. pl. my·o·car·di·a The muscular tissue of the heart. my′o·car′di·al adj. adj of or relating to the ... myocardial. (redirected from myocardial injury). Also found in: Medical.. Related to myocardial injury: Massive coronary, ... Myocardial injury - definition of myocardial injury by The Free Dictionary https://www.thefreedictionary.com/myocardial+injury ...
BACKGROUND: Dynamic cardiomyoplasty is a relatively new surgical procedure proposed for treatment of severe myocardial failure ... BACKGROUND: Dynamic cardiomyoplasty is a relatively new surgical procedure proposed for treatment of severe myocardial failure ... and an increase of flow area during atrial contraction (39 +/- 4 versus 88 +/- 9 mL, P = .001). CONCLUSIONS: Our detailed ...
Effect of disruption of the nNOS gene on myocardial calcium current and contraction ... Effect of disruption of the nNOS gene on myocardial calcium current and contraction ... Effect of disruption of the nNOS gene on myocardial calcium current and contraction ...
NO may also mediate the parasympathetic control of myocardial function. This is supported by the observations that NOS3, the ... Muscarinic and beta-adrenergic regulation of heart rate, force of contraction and calcium current is preserved in mice lacking ...
History of myocardial infarction or coronary artery disease. *Severe left ventricular hypertrophy (wall thickness , 1.5 cm by ... Premature Ventricular Contractions (PVCs) and Blood Pressure Control. The safety and scientific validity of this study is the ... The purpose of this study is to determine if reduction in premature ventricular contraction (PVC) burden results in a decrease ... Frequent symptomatic premature ventricular contractions (PVCs) (,10% of total QRSs on a 24-hour Holter) ...
Myocardial revascularization is performed by an apparatus and method which forms channels in the myocardium from inside the ... System for electrosurgical tissue contraction. US20040225195 *. 8 Jun 2004. 11 Nov 2004. Spence Paul A.. Device to permit ... Myocardial revascularization. US6595979. 23 Oct 2001. 22 Jul 2003. Myocardial Therapeutics, Inc.. Methods for sterile ... Myocardial Therapeutics, Inc.. Sterile aspiration/reinjection systems. US6796963. 23 Oct 2001. 28 Sep 2004. Myocardial ...
Only attempt have persistent bacteraemia; myocardial contraction.. Excessive fat and to avoid intravascular injection. The new ... Myocardial territories supplied by the individual family history. Deaths fall inferiorly because of letter sounds like this, ...
Segmental myocardial contraction. Assessment of regional myocardial function can be improved by characterization of segmental ... Myocardial contraction is a complex process that occurs in 4 dimensions in both a global and segmental domain. Since segmental ... These newer measures of segmental myocardial contraction have been used in many different ways to evaluate patients with ... This may be particularly true in the setting of acute myocardial infarction where hyperdynamic contraction of remote regions ...
Conclusions - Myocardial contraction and relaxation were reduced in the mutant β-myosin heavy chain-glutamic acid403 transgenic ... Conclusions - Myocardial contraction and relaxation were reduced in the mutant β-myosin heavy chain-glutamic acid403 transgenic ... Conclusions - Myocardial contraction and relaxation were reduced in the mutant β-myosin heavy chain-glutamic acid403 transgenic ... Conclusions - Myocardial contraction and relaxation were reduced in the mutant β-myosin heavy chain-glutamic acid403 transgenic ...
  • Severity of contraction abnormalities after acute myocardial infarction in man: response to nitroglycerin. (ahajournals.org)
  • We suggest that myocardial velocity gradient has potential for the quantitative assessment of regional left ventricular contraction abnormalities in patients. (nih.gov)
  • Some patients with left bundle branch block (LBBB) show perfusion abnormalities after an exercise test using myocardial scintigraphy despite normal findings on coronary angiography ( [1-3] ). (onlinejacc.org)
  • Study objectives: Reversible myocardial contraction abnormalities are usually observed in patients with acute ischemic syndromes caused by coronary artery disease. (elsevier.com)
  • In this study, we report the occurrence of reversible anterior-apical contraction abnormalities in patients with an acute noncardiac illness. (elsevier.com)
  • Mechanisms other than myocardial ischemia may lead to the occurrence of reversible regional myocardial contraction abnormalities. (elsevier.com)
  • Because myocyte dysfunction and disarray are the primary abnormalities in HCM, we reasoned that tissue Doppler imaging could identify contraction and relaxation abnormalities, irrespective of hypertrophy, in a transgenic rabbit model of human HCM. (elsevier.com)
  • Using a modified version of troponin C (TnC L48Q), their study showed it can enhance or therapeutically preserve heart function and cardiovascular performance in mice without harmful effects commonly seen with other agents that increase heart muscle contraction. (eurekalert.org)
  • This mechanical muscle contraction response is regulated by entry of calcium ions into the cell. (jove.com)
  • Creatine readily combines with phosphate to form phosphocreatine, or creatine phosphate, which is present in muscle, where it serves as the storage form of high-energy phosphate necessary for muscle contraction. (thefreedictionary.com)
  • of importance in muscle contraction. (thefreedictionary.com)
  • During the past century, physiologists have made steady progress in elucidating the molecular mechanisms of muscle contraction. (biologists.org)
  • However, this progress has so far failed to definitively explain the high force and low energy cost of eccentric muscle contraction. (biologists.org)
  • Vascular smooth muscle contraction is suppressed by feedback dilation mediated by the endothelium. (sciencemag.org)
  • The aim of this study was to clarify how the myocardium is hypoperfused by left ventricular (LV) asynchronous contraction. (onlinejacc.org)
  • Myocardial revascularization is performed by an apparatus and method which forms channels in the myocardium from inside the ventricular cavity without penetrating the full thickness of the ventricular wall. (google.co.uk)
  • emitting channel forming energy from said fiber end in an amount sufficient to form a channel in the ventricular wall into the myocardium to thereby increase myocardial blood flow from the endocardium to the myocardium after the fiber end is directed to the desired channel forming site. (google.co.uk)
  • Recent studies showed that the presence of viable myocardium was associated with a greater likelihood of survival in patients with coronary artery disease and LV dysfunction, but the assessment of myocardial viability did not identify patients with survival benefit from revascularization, as compared with medical therapy alone. (hindawi.com)
  • Movement of the tag ( 102 ) relative to the myocardium ( 100 ) is tracked so as to monitor movement and/or de formation of the wall tissue and assess myocardial viability. (freepatentsonline.com)
  • At the cellular level, altered cardiac excitation-contraction coupling has been identified as a major vehicle of impaired cardiac performance. (aspetjournals.org)
  • However, prominent species-specific differences exist in cardiac excitation-contraction coupling and in the relative roles of extracellular and intracellular Ca(2+) sources among the teleostean fish. (nih.gov)
  • Consequently excitation-contraction coupling of the fish cardiac myocytes is not a fixed entity, but rather a highly variable and malleable process that enables fish to have an appropriate cardiac scope to exploit a diverse range of environments. (nih.gov)
  • Studies of the expression and regulation of the intercellular channel proteins in cardiac excitation-contraction coupling. (nii.ac.jp)
  • Isoflurane (ISO) is known to depress cardiac contraction. (aspetjournals.org)
  • Introduction: Cardiac contraction significantly degrades quality and quantitative accuracy of gated myocardial perfusion SPECT (MPS) images. (elsevier.com)
  • Conclusion: A reversible cardiac contraction abnormality of the anterior wall and apex of the left ventricle can complicate the clinical course of critically ill patients in the absence of significant coronary artery disease. (elsevier.com)
  • In the catheterization laboratory postintervention, conventional function parameters remained stable but systolic myocardial velocities decreased significantly in all segments. (elsevier.com)
  • Torsion gives useful additional information about myocardial tissue performance in both systolic and diastolic function. (biomedsearch.com)
  • 5 The bold straight line shows the normal end systolic pressure-volume relationship (ESPVR), defining ventricular contraction. (bmj.com)
  • The delay to the earliest regional myocardial contraction, 33 ms after paced electrical stimulation, was related to the frame rate of image acquisition. (elsevier.com)
  • Abstract The study of myocardial contractility, based on the new anatomical concepts that govern cardiac mechanics , represents a promising strategy of analysis of myocardial adaptations related to physical training in the context of post- infarction . (bvsalud.org)
  • Case Study 2006 Myocardial Infarction Sharon Thomas Waitakere Hospital Abstract Of This Case Study Have you ever wanted to know what a Myocardial Infarction is and what its all about. (markedbyteachers.com)
  • However, less is known about how cholesterol depletion might affect cardiomyocyte physiology and contraction dynamics. (nature.com)
  • Cardiac neuronal nitric oxide synthase isoform regulates myocardial contraction and calcium handling. (ox.ac.uk)
  • Muscarinic and beta-adrenergic regulation of heart rate, force of contraction and calcium current is preserved in mice lacking endothelial nitric o. (nih.gov)
  • Muscarinic and beta-adrenergic regulation of heart rate, force of contraction and calcium current is preserved in mice lacking endothelial nitric oxide synthase. (nih.gov)
  • The team, led by Jonathan Davis, an associate professor and biophysicist with The Ohio State University Davis Heart and Lung Research Institute, developed a protein engineering approach by tailoring the heart's ability to respond to calcium, which is the signal for contraction. (eurekalert.org)
  • Many strategies increase the calcium signal to improve heart contraction. (eurekalert.org)
  • Role of L-type calcium channels on halothane-induced myocardial depression in cultured rat ventricular myocytes. (nii.ac.jp)
  • The evolution of premature ventricular contractions (PVCs) in acute myocardial infarction was studied by recording bipolar potentials from the left ventricle before and after coronary artery occlusion in dogs. (northwestern.edu)
  • Current guidelines suggest evaluating patients with premature ventricular contractions (PVCs) and associated risk factors for underlying coronary artery disease (strength of recommendation [SOR]: C, expert opinion). (umsystem.edu)
  • Myocardial perfusion was assessed by contrast echocardiography. (onlinejacc.org)
  • Myocardial perfusion was assessed by using myocardial contrast echocardiography (MCE) in dogs with asynchronous contraction induced by ventricular pacing. (onlinejacc.org)
  • The Action of Apelin-12 and Its Analog on Hemodynamics and Cardiac Contractile Function of Rats With Isoproterenol-Induced Myocardial Lesion]. (nextbio.com)
  • CONCLUSIONS Markers of reduced long axis contraction may provide simple and reliable indices of subclinical left ventricular dysfunction in asymptomatic patients with severe aortic regurgitation. (bmj.com)
  • It is a challenge to recognise patients with subclinical myocardial dysfunction in order to operate early enough to prevent postoperative heart failure, but not so early as to subject them to unnecessary operative risks and morbidity related to prosthetic valves. (bmj.com)
  • The present findings have potential translational value because of the efficiency and efficacy of HNO on ISO-induced myocardial contractile dysfunction. (aspetjournals.org)
  • For example, endogenous SO[sub]2 was found to prevent the isopropanol-induced myocardial injury , acting as an antioxidant and a protector against the mitochondrial dysfunction. (thefreedictionary.com)
  • Stunning is another form of reversible segmental myocardial dysfunction in the setting of normal myocardial perfusion. (hindawi.com)
  • Myocardial dysfunction in sepsis: no role for NO? (bmj.com)
  • To test this hypothesis, we have investigated myocardial Ca2+ handling and contractility in nNOS knockout mice (nNOS-/-) and in control mice (C) after acute nNOS inhibition with 100 micromol/L L-VNIO. (ox.ac.uk)
  • However, traditional indices of myocardial function, including cardiac and stroke volume index and ejection fraction, may be inaccurate as a significant depression in contractility can be masked by changes in heart rate, preload, and afterload. (bmj.com)
  • Conceivably, this may enable patients to maintain a normal stroke volume and cardiac indices, despite a profound loss of myocardial contractility, via the Frank-Starling mechanism (fig 1). (bmj.com)
  • We assessed left ventricular wall motion in 11 normal subjects, 14 patients with an old myocardial infarction (anteroseptal in 7, posterior in 7) and 8 patients with dilated cardiomyopathy. (nih.gov)
  • Nuclear cardiology techniques, dobutamine echocardiography and positron emission tomography are used to assess myocardial viability. (hindawi.com)
  • Radio-tracer (11C-glucose) and positron emission tomography quantification of myocardial glucose utilization rate. (clinicaltrials.gov)
  • This study was performed to assess a new indicator of regional left ventricular contraction determined by a two-dimensional tissue Doppler imaging technique. (nih.gov)
  • Tissue Doppler velocity was corrected by the Doppler angle of incidence after the hypothetical center of contraction was set. (nih.gov)
  • These results demonstrate that regional left ventricular contraction can be quantitatively assessed by the myocardial velocity gradient derived from two-dimensional tissue Doppler imaging. (nih.gov)
  • So myocardial referring to muscle, muscle of the heart, and infract referring to lack of oxygen causing death of tissue. (khanacademy.org)
  • Intercalated discs support synchronized contraction of cardiac tissue. (wikipedia.org)
  • Evaluating the site of myocardial ischemia before coronary angioplasty: a role for the Dipyridamole-echocardiography test. (fishpond.com.au)
  • Monocytes: protagonists of infarct inflammation and repair after myocardial infarction. (semanticscholar.org)
  • Fibrotic rigidification following a myocardial infarct is known to impair cardiac output, and it is also known that cardiomyocytes on rigid culture substrates show a progressive loss of rhythmic beating. (biologists.org)
  • So myocardial infarct, lack of of oxygen to heart muscle causing death of that heart muscle. (khanacademy.org)
  • From the SA node, impulses then spread through the atrial conduction pathways which results in contraction of both atria. (scribd.com)
  • Ultrastructure, molecular composition and electrophysiological properties of cardiac myocytes and functional characteristics of the fish heart suggest that cycling of extracellular Ca(2+) is generally more important than intracellular cycling of Ca(2+) stores of the sarcoplasmic reticulum (SR) in activating contraction of fish cardiac myocytes. (nih.gov)
  • We analyzed the expression, phosphorylation, and localization of the major cardic gap-junction protein connexin 43 during the establishment of a synchronized contraction in confluent monolayrs of primary cultured neonatal rat cardiac myocytes, combined with a functional assay of gap junctions by the microinjection-dye transfer method. (nii.ac.jp)
  • The expression, phosphorylation, and localization of connexin 43 and gap-junctional intercellular communication during the establishment of a synchronized contraction cultured neonatal rat cardiac myocytes. (nii.ac.jp)
  • Effect of 2-deoxyglucose, a metabolic inhibitor, on spontaneous contraction and adrenoceptor responsiveness in cultured rat ventricular myocytes. (nii.ac.jp)
  • Additional signs indicating forceful myocardial contraction are: Alternating bundles of hypercontracted myocytes with hyperdistended ones. (wikipedia.org)
  • Myocardial infarction (MI) due to coronary artery disease is a leading cause of death in the United States, where more than 1 million people have acute myocardial infarctions (AMIs) each year. (medscape.com)
  • Lowering blood pressure reduces the risk of fatal and nonfatal cardiovascular events, primarily strokes and myocardial infarctions. (rxlist.com)
  • Certain isozymes are elevated in plasma following myocardial infarctions. (thefreedictionary.com)
  • So whereas before you had lots of blood flowing through your coronary artery, and therefore your cardiomyocytes were getting lots of oxygen out of that blood, now, because of that huge clot that's in the way, there's way less blood flow in that coronary artery, right? (khanacademy.org)
  • When the catheter is placed in a coronary artery obstruction, inflation of the balloon produces transient myocardial ischemia. (fishpond.com.au)
  • The present study points to a potential clinical application of the parameters of ventricular contraction mechanics analysis , especially radial strain , to discriminate post- infarction myocardial adaptations between patients submitted or not to aerobic training programs . (bvsalud.org)
  • The purpose of this study is to determine if reduction in premature ventricular contraction (PVC) burden results in a decrease in blood pressure, sympathetic outflow, plasma catecholamines and an improvement in baroreflex gain. (clinicaltrials.gov)
  • For other discussions on myocardial infarction, see Myocardial Infarction , Right Ventricular Infarction , Imaging of Acute Myocardial Infarcts , and Use of Cardiac Markers in the Emergency Department . (medscape.com)
  • About 90% of patients who have an acute myocardial infarction (AMI) develop some form of cardiac arrhythmia during or immediately after the event. (medscape.com)
  • Zhu, Protective effect of ocotillol on acute myocardial injury induced by lad in rat, J Mol Cell Cardiol. (thefreedictionary.com)
  • Slow ventricular activation in acute myocardial infarction. (northwestern.edu)
  • Fingerprint Dive into the research topics of 'Slow ventricular activation in acute myocardial infarction. (northwestern.edu)
  • Patients with acute myocardial infarction and pulmonary. (drugs.com)
  • 3 Heart failure is becoming increasingly common as the U.S. population ages and survival rates after acute myocardial infarction increase. (aafp.org)
  • In a case-control study of subjects in the Boston area, we found a strong and significant positive association between the intake of trans fatty acids, assessed with the use of dietary questionnaires, and the risk of acute myocardial infarction. (junkscience.com)
  • The results of the only large study, which included 671 men with acute myocardial infarction from eight European countries, were inconclusive. (junkscience.com)
  • In particular, the analyses are necessary for the patients with the age above 50 years and the patients already having the cardiovascular problems owing to the pulmonary edema, acute myocardial infarction, and primary cardiac death [ 4 ]. (hindawi.com)
  • 1. Effects of acute myocardial ischemia and reperfusion in conscious animals. (fishpond.com.au)
  • However, quantitative assessment of regional left ventricular contraction is still difficult because of the effects of the Doppler angle of incidence and parallel motion of the whole heart. (nih.gov)
  • The combination of hemodynamic and biochemical parameters with morphological information from the coronary angiogram can be utilized for the quantification of myocardial involvement and the success of coronary dilatation with angioplasty. (fishpond.com.au)
  • 13) Other studies have demonstrated that RIPC using brief ischemia and reperfusion of the upper limb could reduce myocardial injury in adult patients undergoing CABG surgery. (thefreedictionary.com)
  • In the isolated perfused guinea-pig heart, the increases in isotonic contraction and in cyclic AMP, produced by 2 μg of histamine were significantly and almost completely inhibited in the presence of 2 mg of burimamide, whereas the adrenergic β-receptor blocking drug Kö 592 (50 μg) was ineffective. (springer.com)
  • Traction force microscopy shows that lowering cholesterol increases the rate of cell contraction and generates defects in cell relaxation. (nature.com)
  • Increases the force of myocardial contraction. (unboundmedicine.com)
  • The aim of this study was to clarify how myocardial perfusion is impaired by asynchronous contraction. (onlinejacc.org)
  • The largest and most consistent cardiovascular outcome benefit has been a reduction in the risk of stroke , but reductions in myocardial infarction and cardiovascular mortality also have been seen regularly. (rxlist.com)
  • Patients aged above 55 years with cardiovascular disease/cerebrovascular disease and diabetes will have more risk of different cardiovascular-related problems such as heart failure, valvular heart disease, myocardial infarction, and pulmonary vascular disease. (hindawi.com)
  • 3 Cocaine use is associated with cardiovascular diseases including myocardial infarction (MI), arrhythmias, congestive heart failure (CHF), aortic dissection, endocarditis, and cardiomyopathy. (uspharmacist.com)
  • Subsequently, the myocardial velocity gradient between the endocardium and epicardium was determined from the velocity profile along each radial line from the center of contraction by using least squares linear regression. (nih.gov)
  • Isovolumic contraction acceleration is the slope of the upstroke of the isovolumic contraction wave (IVA = peak velocity/acceleration time). (elsevier.com)
  • The velocity of the blood during atrial contraction is the 'A' (for atrial) filling velocity. (clinicaltrials.gov)
  • Conclusions - Myocardial contraction and relaxation were reduced in the mutant β-myosin heavy chain-glutamic acid 403 transgenic rabbit model of human HCM, irrespective of the presence or absence of LVH. (elsevier.com)
  • Conclusions: Device closure of ASD results to an acute transient decrease of regional myocardial velocities in the LV and RV, whereas the load-insensitive marker isovolumic acceleration remained stable. (elsevier.com)
  • CONCLUSIONS -Young diabetic patients already have significant changes in left ventricular dimensions and myocardial relaxation, with the girls clearly being more affected. (diabetesjournals.org)
  • 5. Wall thickening and motion in transient myocardial ischemia: Similarities and discrepancies between different models of ischemia in man (Prinzmetal's angina, coronary angioplasty, Dipyridamole test). (fishpond.com.au)
  • Heat rate and force of contraction are controlled by the cardiac control center in the medulla of the brain. (scribd.com)
  • 0.05) increased the contractile force and membrane action potential duration at 50% and 90% repolarization levels both in normothermia and in hypothermia, whereas the duration of the contraction was not significantly changed. (lu.se)
  • CONCLUSION: Cooling to 32 degrees C significantly prolongs the myocardial action potential and the contraction duration. (lu.se)
  • Both myocardial and skeletal muscle cells are striated. (springer.com)
  • Myocardial contraction and relaxation. (elsevier.com)
  • isovolumetric relaxation time [IVRT] 66 ± 8 vs. 58 ± 8 ms) compared with female control subjects, suggesting delayed myocardial relaxation. (diabetesjournals.org)
  • After 45 min of equilibration at 37 degrees C or 32 degrees C, resting and action potentials, time to peak contraction and contractile force were recorded during pacing with a frequency of 60/min. (lu.se)
  • Here, isolated embryonic cardiomyocytes cultured on a series of flexible substrates show that matrices that mimic the elasticity of the developing myocardial microenvironment are optimal for transmitting contractile work to the matrix and for promoting actomyosin striation and 1-Hz beating. (biologists.org)
  • This fundamental response depends on myogenic tone, an ongoing pressure-induced vascular smooth muscle cell contraction in small arteries that can be rapidly modulated by perivascular nerves, autacoids, the extracellular accumulation of metabolites, and the endothelium ( 1 , 2 ). (sciencemag.org)
  • And remember, in medicine, we call heart attacks myocardial infarcts. (khanacademy.org)
  • the complications are myocardial infarction, cardiac death, and cardiac arrest. (hindawi.com)
  • The effects of inhalational anesthetic agents on myocardial contraction have been the focus of extensive investigations for many years, and the depression of force development by different inhalational agents has been repeatedly shown. (aspetjournals.org)
  • To quantify intrinsic myocardial depression, an assessment of left ventricular performance using load independent techniques is therefore required. (bmj.com)
  • An understanding of how to control myocardial ageing is key to developing new strategies to improve the management of medical conditions common in the rapidly expanding ageing population for example, heart failure and aortic stenosis. (heartfoundation.org.au)
  • This project aims to use big data and machine learning to integrate echo parameters, clinical and laboratory data to improve prognostication and risk assessment of the contributions of myocardial ageing to aortic stenosis and heart failure. (heartfoundation.org.au)
  • The pattern of left ventricular diastolic filling changed, with a decrease of early peak flow (231 +/- 20 versus 217 +/- 21 mL/s, P = .022), of deceleration time (163 +/- 28 versus 116 +/- 26 seconds, P = .001), and of flow area during rapid filling (105 +/- 15 versus 75 +/- 12 mL, P = .004) and an increase of flow area during atrial contraction (39 +/- 4 versus 88 +/- 9 mL, P = .001). (mendeley.com)
  • At rest, there were no differences between the groups in ejection fraction, left ventricular diameter indices, wall stress, and short axis contraction. (bmj.com)
  • residual blood in the atria, is emptied during diastole by atrial contraction. (clinicaltrials.gov)
  • Regulation of LTCC opening and closing events is fundamental to guarantee a synchronous Ca 2+ signaling 19 that ultimately leads to cardiomyocyte contraction. (nature.com)
  • It is known that extracellular Ca 2+ plays a pivotal role in neonatal cardiomyocyte contraction since those cells lack t-tubules 11 that are fundamental structures for the Ca 2+ -induced-Ca 2+ -release mechanism for contraction in adult cardiomyocytes 21 . (nature.com)
  • INTRODUCTION: Myocardial contraction fraction (MCF) is the ratio of left ventricular (LV) stroke volume to myocardial volume and may serve as a measure of appropriateness of LV mass. (ahajournals.org)
  • MACE were: CV death, myocardial infarction (MI), stroke or new heart failure (HF). (ahajournals.org)
  • Withholding angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin II receptor blockers (ARBs) 24 hours before noncardiac surgery has been associated with a 30-day lower risk for all-cause death, stroke, myocardial injury , and intra operative hypotension (18% adjusted relative risk reduction). (thefreedictionary.com)