[Effect of verapamil on left ventricular hypertrophy induced by isoproterenol]

We evaluated whether verapamil (VERA) has a protective effect on left ventricular hypertrophy (LVH) induced by Isoproterenol (ISO) in rat.

Seventy two male adult rats were divided in four groups and treated accordingly during eight days: Control (CON), VERA (10 mg/kg), ISO (0.3 mg/kg) and VERA + ISO. It was measured in 10 animals from each group heart rate, blood pressure, left ventricle dry weight and ratio between left ventricular weight (LVW) and rat weight. Samples were taken from the left ventricle to be examined by light microscopy.

LVW of the CON group was 0.145 g, of VERA was 0.144 g, of ISO with 0.201 g, and of VERA + ISO was 0.148 g. The difference between ISO group and others was statistically significant (P < 0.05). The LVW/W ratio also showed similar result. The myocardial pattern induced by ISO was left hypertrophy and collagen content increase. In VERA + ISO group it was found a protective effect to hypertrophy (ISO group 97% vs VERA + ISO 87%; p < 0.001) and increased collagen content.

VERA prevents the deleterious effects of ISO in the myocardium. Probably this action is due to prevention the myocardial hypertrophy and proliferation of collagen tissue.