It has been shown that converting
enzyme inhibitors (CEI) attenuate ventricular dilatation and
hypertrophy after
myocardial infarction. In most studies, CEI treatment was started when ventricular dilatation and
hypertrophy were already well under way. Therefore, we studied the effects on ventricular dilatation and
hypertrophy, when CEI treatment was started in the acute phase of
myocardial infarction. Immediately after a
sham-operation or
myocardial infarction in rats (
sham: n = 8; MI: n = 17), treatment with
zofenopril, a novel
ACE-inhibitor, was started and continued during 42 days (long-term treatment). In a second group of rats,
zofenopril was administered only during the first 5 days after
myocardial infarction (short-term treatment); these rats were not treated with
zofenopril during the remaining period of 37 days (
sham: n = 5; MI: n = 13). Untreated rats served as controls (
sham: n = 9; MI: n = 24). The results from this study showed that long-term treatment with
zofenopril caused a significant reduction of left ventricular cavity volume in rats with moderate-to-large
infarctions, which was accompanied by a significant reduction in the ratio of total heart weight to
body weight. However, short-term treatment with
zofenopril did not significantly reduce ventricular volume or total heart weight. Finally, both long- and short-term treatment resulted in a small, but statistically significant, reduction of septal wall thickness in
sham-operated and infarcted rats. We conclude that CEI
therapy decreases ventricular dilatation and
hypertrophy after
myocardial infarction, only when treatment is continued during the chronic phase.(ABSTRACT TRUNCATED AT 250 WORDS)