Contribution of left ventricular contraction to the generation of right ventricular systolic pressure in the human heart.

To determine whether left ventricular (LV) contraction contributes to the generation of right ventricular (RV) systolic pressure in humans, LV and RV pressures and their first derivative (dP/dt) were recorded simultaneously with micromanometer-tipped catheters in 11 conscious subjects. Seven subjects had normal LV and coronary angiograms. Four subjects had moderate LV dysfunction (resting ejection fraction 0.40 to 0.50), and three of these had coronary artery disease. During normal sinus rhythm, LV contraction slightly preceded RV contraction (mean 20 msec), and LV and RV dP/dt recordings showed single positive systolic peaks that were coincident. During endocardial pacing of the RV free wall, RV contraction preceded LV contraction (mean 23 msec) and two systolic RV dP/dt peaks were recorded, the first (peak I) occurring significantly before (mean +/- SD = 67 +/- 23 msec, p less than .01), and the second (peak II) coincident with the single systolic LV dP/dt peak. RV ectopic beats produced a similar RV dP/dt pattern, with peak I occurring 63 +/- 11 msec (p less than .01) before, and peak II coincident with the single LV dP/dt peak. Conversely, during LV ectopic beats, LV contraction preceded RV contraction (mean 63 msec) and two systolic RV dP/dt peaks were recorded, but peak I was coincident with the single LV dP/dt peak, while peak II occurred significantly later (63 +/- 26 msec, p less than .01). In two subjects right bundle branch block produced similar findings. In three subjects left bundle branch block produced little ventricular asynchrony (mean 14 msec), but did delay the development of peak LV dP/dt after LV contraction.(ABSTRACT TRUNCATED AT 250 WORDS)