Right ventricular trabeculae demonstrated a 35% greater maximum mechanical efficiency than left ventricular trabeculae (13.6% vs. 10.2%), offset by the greater metabolic cost of activation in the LV.
The higher mechanical efficiency of right ventricular trabeculae compared to left ventricular trabeculae is driven by differences in activation heat rather than crossbridge efficiency.
Tasa de eventos absoluta: 13.6% vs 10.2%
We compare the energetics of right ventricular and left ventricular trabeculae carneae isolated from rat hearts. Using our work-loop calorimeter, we subjected trabeculae to stress-length work (W), designed to mimic the pressure-volume work of the heart. Simultaneous measurement of heat production (Q) allowed calculation of the accompanying change of enthalpy (H = W + Q). From the mechanical measurements (i.e. stress and change of length), we calculated work, shortening velocity and power. In combination with heat measurements, we calculated activation heat (Q(A)), crossbridge heat (Q(xb)) and two measures of cardiac efficiency: 'mechanical efficiency' ((mech) = W/H) and 'crossbridge efficiency' ((xb) = W/(H - Q(A))). With respect to their left ventricular counterparts, right venticular trabeculae have higher peak shortening velocity, and higher peak mechanical efficiency, but with no difference of stress development, twitch duration, work performance, shortening power or crossbridge efficiency. That is, the 35% greater maximum mechanical efficiency of right venticular than left ventricular trabeculae (13.6 vs. 10.2%) is offset by the greater metabolic cost of activation (Q(A)) in the latter. When corrected for this difference, crossbridge efficiency does not differ between the ventricles.
Han et al. (Tue,) conducted a other in Rat heart trabeculae carneae energetics. Right ventricular trabeculae vs. Left ventricular trabeculae was evaluated on Maximum mechanical efficiency. Right ventricular trabeculae demonstrated a 35% greater maximum mechanical efficiency than left ventricular trabeculae (13.6% vs. 10.2%), offset by the greater metabolic cost of activation in the LV.