Influence of nifedipine on ventricular function and myocardial hypertrophy in spontaneously hypertensive rats.

We compared left ventricular (LV) hemodynamics, LV muscle mass (LVMM), and LV geometry of 13 spontaneously hypertensive rats (SHRs) treated for 20 weeks with nifedipine (30 mg/kg/day) with those of 11 age-matched untreated SHRs. LVMM, LVMM related to end-diastolic volume (LVMM/EDV), LV pressure (PLV), systolic wall stress (Tsyst), ejection fraction (EF), cardiac index (CI), and isovolumetric contractility indices (dP/dtmax, IP, t-dP/dtmax, and VCE) were determined. Nifedipine treatment lowered PLV from 170 to 136 mm Hg and Tsyst from 222 to 194 10(3) dyn/cm2.