Topic
Anrep effect
About: Anrep effect is a research topic. Over the lifetime, 41 publications have been published within this topic receiving 1418 citations.
Papers
TL;DR: The data indicate that the second force phase and the increase in [Ca(2+)](i) transient after stretch result from activation of the Na(+)/H(+) exchanger (NHE) increasing [Na(+)] (i) and leading to a secondary increase in [/Ca( 2+](i), which reflects an autocrine-paracrine mechanism.
Abstract: —Myocardial stretch produces an increase in developed force (DF) that occurs in two phases: the first (rapidly occurring) is generally attributed to an increase in myofilament calcium responsiveness and the second (gradually developing) to an increase in [Ca2+]i. Rat ventricular trabeculae were stretched from ≈88% to ≈98% of Lmax, and the second force phase was analyzed. Intracellular pH, [Na+]i, and Ca2+ transients were measured by epifluorescence with BCECF-AM, SBFI-AM, and fura-2, respectively. After stretch, DF increased by 1.94±0.2 g/mm2 (P<0.01, n=4), with the second phase accounting for 28±2% of the total increase (P<0.001, n=4). During this phase, SBFI340/380 ratio increased from 0.73±0.01 to 0.76±0.01 (P<0.05, n=5) with an estimated [Na+]i rise of ≈6 mmol/L. [Ca2+]i transient, expressed as fura-2340/380 ratio, increased by 9.2±3.6% (P<0.05, n=5). The increase in [Na+]i was blocked by 5-(N-ethyl-N-isopropyl)-amiloride (EIPA). The second phase in force and the increases in [Na+]i and [Ca2+]...
217 citations
TL;DR: In this paper, it was shown that the positive inotropic effect after an abrupt increase in systolic pressure (Anrep effect) is the recovery from subendocardial ischemia induced by the increase and subsequently corrected by vascular autoregulation of the coronary bed.
Abstract: Evidence is presented supporting the hypothesis that the positive inotropic effect after an abrupt increase in systolic pressure (Anrep effect) is the recovery from subendocardial ischemia induced by the increase and subsequently corrected by vascular autoregulation of the coronary bed. Major evidence consists of data obtained from an isolated heart preparation showing that the Anrep effect can be abolished with coronary vasodilation, and that with an abrupt increase in systolic pressure there is a significant reduction in the distribution of coronary flow to subendocardial layers of the ventricle. Furthermore, the intracardiac electrocardiogram shows S-T segment and T wave changes after an abrupt increase in ventricular pressure similar to that noted after coronary constriction. Major implications are that normally there may be ischemia of the subendocardial layers tending to reduce myocardial contractility which may account, in part, for the positive inotropic effect of various coronary vasodilators; that with an abrupt increase in ventricular pressure the subendocardium is rendered temporarily ischemic, placing the heart in jeopardy from arrhythmias until this is corrected; and that end-diastolic pressure and the intracardiac electrocardiogram may provide a means of evaluating the adequacy of circulation to subendocardial layers in diseased ventricles when systolic pressure is abruptly increased.
90 citations
TL;DR: The RV of sheep responded to acute pressure overload by demonstrating enhanced contractility and evidence of the Frank-Starling mechanism without associated change in right ventricular diastolic performance.
Abstract: The first stage of the two-stage arterial switch operation (ASO) for transposition of the great arteries (TGA) is associated with depressed ventricular function and an unstable immediate post-operative course. It is unclear if this is because of the acute increase in afterload of the thin-walled, low-pressure ventricle by pulmonary artery banding (PAB). To determine the acute effects of afterload increase on the contractile function of thin-walled ventricles, we studied the right ventricular pressure-volume relations of seven sheep before and 30 min after PAB using combined pressure-conductance catheters during inflow reduction. Load independent indices of systolic and diastolic performance were derived from these relations. Pulmonary artery banding increased the mean ratio between right and left ventricular systolic pressure from 0.34 +/- 0.05 to 0.64 +/- 0.10, P < 0.05 (mean +/- SD). There were no significant changes in heart rate and end-systolic volume after banding although there was an incremental trend in the end-diastolic volume and stroke volume. Right ventricular output (530 +/- 163-713 +/- 295 mL min (-1), P < 0.05), slope of the end-systolic pressure-volume relation (ESPVR) (3.7 +/- 2.8-10.0 +/- 4.8 mmHg mL (-1), P < 0.05) and slope of the pre-load recruitable stroke work (PRSW) relation (9.6 +/- 1.8-15.0 +/- 3.1 mmHg, P < 0.05) were significantly increased indicating improved contractile state after banding. The diastolic function curve was unchanged after banding although the right ventricle (RV) was operating at a larger end-diastolic volume. Hence, the RV of sheep responded to acute pressure overload by demonstrating enhanced contractility and evidence of the Frank-Starling mechanism without associated change in right ventricular diastolic performance.
62 citations
TL;DR: These findings agree with the hypothesis that transient underperfusion and overperfusions of the subendocardial layers of the left ventricle occur with abrupt increases and decreases in ventricular pressure, respectively.
Abstract: Regional coronary venous oxygen saturation and myocardial oxygen tension (PO2) in isolated dog hearts were measured using two different methods--a new technique of microscopic oximetry and an improved oxygen electrode. Both methods yielded similar results. In studies of the isolated perfused dog heart developing a constant left ventricular systolic pressure, mean coronary venous oxygen saturation of blood in the subendocardial veins of the left ventricle was significantly lower than that in the subepicardial veins. Following abrupt increases in systolic pressure, subendocardial coronary venous saturations fell to even lower levels. Following abrupt decreases in systolic pressure, the mean subendocardial coronary venous oxygen saturation increased to levels above those in the blood of the subepicardial veins. These findings agree with the hypothesis that transient underperfusion and overperfusion of the subendocardial layers of the left ventricle occur with abrupt increases and decreases in ventricular pre...
59 citations
1 Jan 1972
TL;DR: Evidence is presented supporting the hypothesis that the positive inotropic effect after an abrupt increase in systolic pressure (Anrep effect) is the recovery from subendocardial ischemia induced by the increase and subsequently corrected by vascular autoregulation of the coronary bed.
Abstract: A B S T R A C T Evidence is presented supporting the hypothesis that the positive inotropic effect after an abrupt increase in systolic pressure (Anrep effect) is the recovery from subendocardial ischemia induced by the increase and subsequently corrected by vascular autoregulation of the coronary bed. Major evidence consists of data obtained from an isolated heart preparation showing that the Anrep effect can be abolished with coronary vasodilation, and that with an abrupt increase in systolic pressure there is a significant reduction in the distribution of coronary flow to subendocardial layers of the ventricle. Furthermore, the intracardiac electrocardiogram shows S-T segment and T wave changes after an abrupt increase in ventricular pressure similar to that noted after coronary constriction. Major implications are that normally there may be ischenia of the subendocardial layers tending to reduce myocardial contractility which may account, in part, for the positive inotropic effect of various coronary vasodilators; that with an abrupt increase in ventricular pressure the subendocardium is rendered temporarily ischemic, placing the heart in jeopardy from arrhythmias until this is corrected; and that end-diastolic pressure and the intra
52 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2021 | 1 |
| 2020 | 5 |
| 2018 | 1 |
| 2017 | 1 |
| 2015 | 1 |
| 2014 | 3 |