Effects of an early treatment with lisinopril and isosorbide-5-mononitrate on hemodynamics and late ventricular remodelling in rats with 9-week myocardial infarction.

: This study was undertaken to assess whether the converting enzyme inhibitor lisinopril, and the long-acting nitrate, isosorbide-5-mononitrate, affect left ventricle dysfunction and anatomical remodelling in rats with myocardial infarction. Lisinopril, isosorbide-5-mononitrate or vehicle were given to rats (n = 10-14 per group) immediately after coronary artery occlusion (by an intravenous bolus) and then for nine weeks (in drinking water). At the end of the study, left ventricular pressures were measured, the heart arrested in diastole, and infarct size, left ventricular chamber volume and wall thicknesses measured. Lisinopril significantly lowered systemic blood pressure and left ventricular systolic pressure in rats with small ( 15%) infarcts; the weight of the left ventricle (including the septum) was reduced by 24% and 28% in animals with small and large infarcts, respectively. Lisinopril lowered left ventricular end-diastolic pressure (by 33% and 39%) and chamber volume (by 4% and 34%) in rats with small and large infarcts, respectively, compared with controls (NS). The combined anatomical and hemodynamic changes led to a reduction of the circumferential wall stress by 20% and 44% in lisinopril-treated rats with small and large infarcts, respectively (NS). No significant changes were seen in the nitrate-treated hearts compared with controls. Lisinopril, given early after myocardial infarction and continued for nine weeks, significantly affected cardiac hemodynamics and ventricular weights in rats with infarcts of different sizes.(ABSTRACT TRUNCATED AT 250 WORDS)