Left and right ventricular pump function and consequences of having two pumps in one heart. A study on the isolated cat heart.

Abstract

Tanz RD, Marcus SM (1966) Influence of endogenous cardiac catecholamine depletion on the force and rate of isolated heart preparations and their response to ouabain. J Pharamcol Exp Ther 151: 38-45 Thorpe WP (1973) Some effects of caffeine and quinidine on sarcoplasmic reticulum of skeletal and cardiac muscle. Can J Physiol Pharmacol 51: 499-503 Thyrum PT (1974) Inotropic stimuli and systolic transmembrane calcium flow in depolarized guinea pig atria. J Pharmacol Exp Ther 188: 166-179 Tillisch J, Langer GA (1974) Myocardial mechanical responses and ionic exchange in high sodium perfusate. Circ Res 34: 40-50 Tillisch JH, Fung LK, Horn PM, Langer GA (1979) Transient and steady-state effects on sodium and calcium on myocardial contractile response. J Mol Cell Cardiol 11: 137-148 Weingart R, Kaas RS, Tsien RW (1978) Is digitalis inotropy associated with enhanced slow inward calcium current? Nature 217:389-392 Weiss R, Tritthart H, Walter B (1974) Correlation of Na-withdrawal effects on Ca-mediated action potentials and contractile activity in cat ventricular myocardium. Pfluegers Arch 350: 299-307 Wendt IR, Langer GA (1977) The sodium-calcium relationship in mammalian myocardium. Effects of sodium deficient perfusion on calcium fluxes. J Mol CellSUMMARY We compared pump function of left and right ventricles in isolated ejecting cat hearts in which the natural series arrangement between the two sides of the heart was broken. The relationship between mean ventricular pressure and output obtained by varying the arterial load, the so-called pump function graph, and the mean external power output found at the various load levels, was taken as the basis for the comparison. The way in which pressures and flow generated by the right ventricle are changed by alterations in resistance and compliance of the loading arterial system, is qualitatively similar to what has been found in a previous study for the left side of the heart, in spite of the structural differences. The right ventricular pump function curve differs from the left ventricular curve in the absolute scale for the mean pressure axis, but if the scale is adjusted appropriately, the two curves look alike. Both ventricles appear matched to the input impedances of their respective arterial systems because both of them generate the maximum external power under the normal loading conditions. Right ventricular pump function is dependent on the left ventricular contraction mode. The presence of an isovolumic beat on the left side of the heart enhances right ventricular pump function. This is in contrast to the very small effect of the right ventricular contraction pattern on the pump function of the left side of the heart. Circ Res 46: 564-574, 1980STRIKING differences exist between the right and left sides of the heart. However, both ventricles have approximately the same output because of their series arrangement, and both are part of the same muscular structure, the heart. In spite of this tight connection, the two sides must have different pump characteristics refle...

Significance of the Right Ventricular Free Wall in Dogs with and without Pulmonary Constriction.

“…Thus, in the present experiment, the increase in right ventricular volume at ischemia might also modify the left ventricular diastolic pressure-volume relationship, that is, decrease in end-diastolic length with no change in enddiastolic pressure, and disturb blood filling to the left ventricle. It has also been pointed out that left ventricular contraction affects right ventricular systolic function through a mechanical interaction between the two ventricles (Elzinga et al 1980). Thus, the decrease in left ventricular systolic pressure appeared to enhance the decreases in right ventricular developed pressure and stroke volume at ischemia.…”

Importance of mitral subvalvular apparatus in terms of cardiac energetics and systolic mechanics in the ejecting canine heart.

“…Recently, several studies have provided evidence that the left ventricle and the arterial circulation interact in such a manner as to optimize cardiac energetics (28)(29)(30)(31)(32)(33)(34)(35)(36) Ee;S at any given EDV (35). In this study, the EJEfS ratio was near unity at baseline (0.91±0.53), suggesting that the ventricle and arterial properties were matched such that external stroke work was maximized; however, Ea/Ee, was not statistically different from 0.5.…”

Describing right ventricular function

“…Since the right ventricle interacts on the left ventricle and vice versa, the question remains to be answered whether an optimal description also should incorporate ventricular direct and/or series interdependency [36,37]. Ventricular interdependency in pulmonary hypertension needs further studies, but accounting for this effect will increase complexity, which may limit clinical usage.…”