Load dependence of cardiac output in biventricular pacing: right ventricular pressure overload in pigs.

Background: The effect of biventricular pacing on stroke volume is believed to be dependent on right ventricular/left ventricular delay, but effects in individual patients are unpredictable. This variability may reflect relative right and left ventricular volume and/or pressure overloads. Accordingly, we tested the hypothesis that the relation of cardiac output to right ventricular/left ventricular delay is load dependent in a pig model of pulmonary stenosis.