Faculdade de Medicina de Botucatu- UNESP

Objective – To evaluate the effects of losartan on ven-tricular remodeling and on survival after myocardial infarction in rats. Methods – After surgical occlusion of left coronary artery, 84 surviving male Wistar rats were divided into two groups: LO treated with losartan (20mg/kg/day, n=33) and NT (n=51), without medication. After 3 months, we analyzed mortality; ventricular to body mass ratio (VM / BM); myocardial hydroxyproline concentration (HOP); isovolumetric pressure, +dp/dt,-dp/dt, and diastolic volu-me/left ventricle mass ratio (VO/LV). Results – Mortality was: LO = 22%, and NT = 47% (p<0.05). Ventricular mass,(VM/BM, mg/g) was 4.14 ± 0.76 and 3.54±0.48, in the NT and LO groups, respectively (p<0.05). HOP (median) was 4.92 υg/mg in the LO and 5.54 υg/g in the NT group (p>0.05). The V0/LV values (median) were 0.24 mL/g in group LO and 0.31 mL/g in group NT (p<0.05) compared to NT group. There were no differences between the groups for +dp/dt and-dp/dt parameters. Conclusion – 1- The use of losartan myocardial infarction causes an attenuation of ventricular remode-ling, bringing about an increased survival, an attenua-tion of ventricular hypertrophy and dilation, and an im-provement of the isovolumetric pressure; 2- the treatment does not modify the myocardial collagen concentration