Differential effects of diltiazem and nitroprusside on left ventricular function in experimental chronic volume overload

Abstract

To compare the hemodynamic effects of a calcium-channel blocker with those of a conventional vasodilator in th awake preinstrumented dog, diltiazem and nitroprusside were administered in equihypotensive infusions before (decrease in mean aortic pressure by 10%; p < .001, n = 6) and after (decrease in mean aortic pressure by 12%; p < .001). By contrast, at mached aortic pressures nitroprusside significantly reduced left ventricular end-diastolic dimension (LVEDD) and pressure (LVEDP) in the same animals before (decrease in LVEDD by 10%, p < .05; decrease in LVEDP by 7 ± 2 mm Hg, p < .001) and after CVO (decrease in LVEDD by 7%, p < .05; decrease in LVEDP by 5 ± 2 mm Hg, p