EFFECTS OF LISINOPRIL UPON CARDIAC-HYPERTROPHY, CENTRAL AND PERIPHERAL HEMODYNAMICS AND NEUROHUMORAL FACTORS IN SPONTANEOUSLY HYPERTENSIVE RATS

Objective: Left ventricular function (LVF) after reversal of left ventricular hypertrophy (LVH) with antihypertensive therapy is still controversial. The present study was undertaken in spontaneously hypertensive rats (SHR) to determine whether LVF of the regressed heart with lisinopril is normally maintained. Design: We compared cardiac function of SHR after reversal of LVH induced by lisinopril with that observed in control SHR and also with effects after a 4-week washout period. Methods: Administration of lisinopril began at 15 weeks of age and continued for 20 weeks. Cardiac index, renal blood flow, leg muscle blood flow, plasma renin activity, atrial natriuretic peptide level, and norepinephrine concentration were determined. Results: Lisinopril decreased body weight, blood pressure and left ventricular weight and increased leg muscle blood flow; cardiac index and renal blood flow were unaltered. Although norepinephrine concentration was unchanged, plasma renin activity increased and atrial natriuretic peptide decreased in treated SHR. Peak left ventricular pumping ability during volume loading was comparable in the two groups. After a 4-week washout period, left ventricular mass and blood pressure increased but remained lower than controls; cardiac index at rest and during volume loading was similar in the two groups. Conclusions: These data indicate that LVF of the regressed heart induced by lisinopril was well preserved at rest, during volume loading and also after spontaneous recurrence of hypertension in SHR.