Acute alterations in systolic ventricular interdependence-mechanical dependence of right ventricle on left ventricle following acute alteration of right ventricular free wall.

The purpose of the study was to examine whether systolic ventricular interdependence can be acutely altered by changes in the mechanical properties of the ventricular wall. In eight acute canine studies, we released an aortic constriction during diastole. We measured right ventricular (RV) pressure changes (dPr) caused by sudden changes in left ventricular (LV) pressure (dPl). Measurements were obtained during control, 10 min after right coronary artery occlusion, and then 15 min after injecting glutaraldehyde into the RV free wall. By superimposing the pressure tracings of the beats immediately before and after the aortic release, the instantaneous pressure difference ratio (dPr/dPl) was calculated during systole. Maximal value of the pressure difference ratio decreased from control 0.11 +/- 0.04 to ischemia 0.08 +/- 0.03; (p < 0.05) and increased with glutaraldehyde 0.15 +/- 0.06; (p < 0.05). Thus, acute ischemia in RV free wall decreased the magnitude of systolic ventricular interdependence from LV to RV, while glutaraldehyde, which stiffens the RV free wall, increased the magnitude.