Effects of the new angiotensin receptor antagonist dipotassium (Z)-2-[[5-ethyl-3-[2'-(1H-tetrazol-5-yl)biphenyl-4-yl]methyl-1,3,4-thiadiazoline-2-ylidene]aminocarbonyl]-1-cyclopentencarboxylate on experimental cardiac hypertrophy and acute left ventricular failure

The cardiovascular effects of dipotassium (Z)-2-[[5-ethyl-3-[2'-(1H-tetrazol-5-yl)biphenyl-4-yl]methyl- 1,3,4-thiadiazoline-2-ylidene] aminocarbonyl]-1-cyclopentencarboxylate CAS 169328-25-0, KRH-594), a new angiotensin II type 1 (AT(1)) receptor antagonist, on pressure-overload cardiac hypertrophy in rats and on acute left ventricular failure in dogs were investigated. In rats with a 2-week abdominal aorta constriction, left ventricular weight (LVW) and systolic blood pressure (SBP) were significantly greater than in sham-operated rats. Oral administration of KRH-594 (10 or 30 mg/kg/day for 2 weeks) reduced the increases in both LVW and SBP. Another AT(1) receptor antagonist, candesartan cilexetil (1 or 3 mg/kg/day for 2 weeks), also prevented this type of cardiac hypertrophy. In anesthetized dogs with a 60-min coronary ligation, left ventricular end-diastolic pressure (LVEDP) and total peripheral resistance (TPR) were raised, whereas the maximum first derivative of left ventricular pressure and cardiac output were both decreased. Intravenous administration of KRH-594 (3 mg/kg) significantly attenuated the increases in both LVEDP and TPR after coronary ligation. These results suggest that KRH-594, by reducing the cardiac afterload, may ameliorate pressure-overload cardiac hypertrophy in rats and produce an improvement in the hemodynamic status of dogs with acute left ventricular failure.