Effect of antiarrhythmic drugs on the postischaemic metabolic recovery of isolated rat hearts

Abstract

In isolated perfused rat hearts, global ischaemia for 20 or 40 min led to a substantial decrease of myocardial ATP, creatine phosphate and glycogen, and to an increase in lactate and glucose-6-phosphate. Subsequent coronary reperfusion was associated with severe tachyarrhythmias (ventricular fibrillation occurring in 40% of the hearts after 20 min of ischaemia, and in 100% after 40 min of ischaemia) and the release of great activities of creatine kinase. Metabolic recovery was obtained only in hearts in which reperfusion-induced fibrillation was lacking. Significant improvement of the metabolic recovery during reperfusion was obtained with corynanthine, a stereoisomer of yohimbine, given in concentrations which prevented reperfusion-induced fibrillation. Moreover, a highly significant decrease of the enzyme release was observed. Similar results were obtained with quinidine. Lidocaine (30 mumol/l) failed to prevent ventricular fibrillation and had no beneficial effect on myocardial metabolism. The effects of these antiarrhythmic drugs are discussed in view of the importance of ventricular fibrillation on postischaemic metabolic recovery.