Abstract

Hypothesis/introduction: Our aim was to investigate whether a non-hypotensive dose of ramiprilat and losartan has myocardial protective effects during myocardial ischemia/reperfusion in vivo. Materials and methods: Three groups of rats were given 10 mg/kg per day of losartan for one (L-1W), four (L-4W) or 10 (L-10W) weeks. Another three groups were given 50 A mu g/kg per day of ramiprilat for one (R-1W), four (R-4W) or 10 (R-10W) weeks. The animals underwent 30 min of left anterior descending artery occlusion and subsequent reperfusion for 120 min. Results: Myocardial infarct size (IS) was reduced in R-1W (28.4 +/- 6.3, p < 0.001), R-4W (27.8 +/- 7.4, p < 0.001), L-4W (31.8 +/- 6, p < 0.05) and L-10W (25.3 +/- 5.7, p < 0.001) groups compared with a saline group (48.3 +/- 7.8). A significant reduction in the number of ventricular ectopic beats (VEBs) was noted in groups R-1W (209 +/- 41, p < 0.01), R-4W (176 +/- 39, p < 0.01), L-4W (215 +/- 52, p < 0.05) and L-10W (191 +/- 61, p < 0.01 vs. saline 329 +/- 48). The incidence of irreversible ventricular fibrillation (VF) and mortality were decreased significantly only in L-10W group. There were no significant decreases in episodes of VT, the incidence of irreversible VF and mortality in all of the groups treated with ramiprilat. Conclusion: These data indicate that losartan and ramiprilat protect the heart against ischemia/reperfusion injury independently of their hemodynamic effects but in a time-dependent manner.