EFFECTS OF ENALAPRIL ON EXERCISE TOLERANCE AND LONGEVITY IN DOGS WITHHEART-FAILURE PRODUCED BY IATROGENIC MITRAL REGURGITATION

This study was conducted to evaluate the effects of enalapril on exerc ise capacity and longevity in dogs with left-sided heart failure produ ced by iatrogenic mitral regurgitation. After surgical creation of mit ral regurgitation, 18 dogs were allocated into replicates according to exercise capacities. One dog in each replicate received placebo, and the other received 0.5 mg/kg of enalapril sid for 9 days and bid there after. Exercise tolerance was studied after 10, 19, 52 to 53, and 80 t o 81 days, respectively. Finally, the percentage of dogs in each group that survived 357 days was compared. The duration of exercise for dog s in the placebo and enalapril groups did not differ at baseline (P > .1) or after 19 days (P > .1). Dogs that received enalapril had signif icantly reduced (P < .001) exercise tolerance at day 10, and significa ntly increased (P = .002) exercise tolerance at days 52 to 53 and 80 t o 81 when compared with controls. At 357 days, 22% of dogs receiving p lacebo were alive, compared with 67% of dogs receiving enalapril; howe ver, these differences were not statistically significant (P = .124). This study shows that enalapril increases exercise tolerance in dogs w ith left-sided heart failure induced by iatrogenic mitral regurgitatio n. Copyright (C) 1996 by the American College of Veterinary Internal M edicine.