Effects of enalapril in cats with pressure overload-induced left ventricular hypertrophy

In order to evaluate the effect of enalapril on haemodynamics and renal function in a pressure overload model, we prepared eight feline models of left ventricular hypertrophy (LVH) by banding of the aortic arch. The LVH cats were assigned to the placebo group or the enalapril group (0.5 mg/kg, PO, sid) 3 months following surgery, and each received its respective drug for 4 weeks. Each week, blood pressure, angiotensin converting enzyme (ACE) activity in blood, and creatinine clearance were measured, and complete blood count (CBC), biochemical examination of the blood, echocardiography, and chest radiography were carried out. The interventricular septum thickness (IVSd, IVSs), fractional shortening (FS), and ejection fraction (EF) increased significantly in the LVH cats following surgery (P<0.05). There was no significant difference between the placebo group and the enalapril group with respect to general physical parameters, CBC, biochemical parameters and renal function. In the enalapril group, systolic arterial pressure, mean arterial pressure, and ACE activity in blood decreased significantly following administration (P<0.05). In addition, the left ventricular free wall thickness in diastole and IVSd decreased significantly following administration (P<0.05). These results suggest that, in a pressure overload model, enalapril (0.5 mg/kg, sid) inhibits cardiac hypertrophy, reduces blood pressure, and does not adversely affect renal function.