EFFECTS OF ANTIARRHYTHMIC AGENTS CLASSIFIED AS CLASS-III GROUP ON ISCHEMIA-INDUCED MYOCARDIAL DAMAGE IN CANINE HEARTS

The cardioprotective effects of antiarrhythmic agents classified as class III, amiodarone, sotalol and E-4031, were investigated in anaesthetized dogs. The left anterior descending coronary artery was occluded for 2 h. Heart mitochondria were prepared from both the ischaemic and non-ischaemic areas, and their function was estimated polarographically. Activities of the lysosomal enzymes, N-acetyl-β-glucosaminidase and β-glucuronidase, were measured in each fraction. Two hour occlusion induced ventricular arrhythmias, and amiodarone, sotalol and E-4031 greatly suppressed the development of arrhythmias. Amiodarone, sotalol and E-4031 significantly protected mitochondria against ischaemia, and prevented ischaemia-induced leakage of lysosomal enzymes. Antiarrhythmic agents classified as class III show cardioprotective effects, which might participate in their antiarrhythmic effect.