Time course of spirapril-induced structural and functional changes after myocardial infarction in rats followed with magnetic resonance imaging.

Structural alterations after myocardial infarction (MI) in rats are usually examined only after death of the experimental animal. Magnetic resonance imaging (MRI) allows repeated and noninvasive measurements of important structural [left ventricular (LV) mass, LV wall thickness, LV chamber radius] as well as function [LV end-systolic and LV end-diastolic volume, stroke volume (SV), ejection fraction (EF)] parameters for a prolonged period. We describe our experience in a series of experiments in rats. Three weeks after MI, infarct size (IS) was determined by MRI and the rats were divided into two groups with equal IS. Three weeks later, treatment with the angiotensin-converting enzyme (ACE) inhibitor spirapril (10 mg/kg in food) or placebo was started