Calcium antagonists prevent early post-infarction ventricular fibrillation

The intravenous administration of either nifedipine (in doses of 5-50 microgram/kg), or nisoldipine (5-1000 microgram/kg) markedly reduced, or abolished, the serious ventricular arrhythmias (tachycardia and fibrillation) that result from acute coronary artery artery ligation in pentobarbitone-anaesthetized rats. Ventricular ectopic activity, which is pronounced in the first 30 min post-ligation period in this model, was also significantly decreased by nifedipine and niludipine (10 and 50 microgram/kg) and by the highest dose (1 mg/kg) of nisoldipine. These results demonstrate the marked efficacy of these calcium antagonists in this experimental model and raise the possibility that, if given prophylactically, they might reduce the incidence of sudden cardiac death following re-infarction in patients.