Cardioprotective actions of a new calcium channel blocker in acute myocardial ischemia.

The ability of anipamil, a calcium channel blocker, to protect ischemic myocardial tissue was investigated in pentobarbital anesthetized cats. Two bolus injections of anipamil (1.0 mg/kg i.v.) or their vehicle (i.e., 95% ethanol) were given 30 and 150 min post-ligation of the left anterior descending coronary artery. Anipamil significantly reduced the elevated S-T segment elevation and T wave amplitude suggesting a moderating influence on cellular ischemia. The drug also significantly blunted the loss in myocardial creatine kinase activity and amino-nitrogen concentrations from ischemic myocardial tissue, compared to cats receiving only the vehicle. These changes are suggestive of a cardioprotective effect of this calcium channel blocker. Since no significant change in the pressure rate index was seen with anipamil, a decrease in myocardial oxygen demand does not appear to be the major mechanism of the cardioprotective action of the agent. Therefore, anipamil protected the heart from ischemic damage, possibly by a direct cytoprotective action.