[The effects of propranolol and sotalol on the electrophysiologic and enzymatic impact of myocardial ischemia induced in vitro in the guinea pig heart].

Antiarrhythmic and cardioprotective effects of propranolol and sotalol were examined by studying their action on cellular electrical activity (recorded using standard microelectrode techniques) and creatine-kinase leakage (measured in the effluent from the experimental bath chamber) in the in vitro guinea-pig left ventricular myocardium exposed to conditions mimicking severe or moderate ischemia. Returning the tissue to the normal conditions was considered as equivalent to ischemic-heart reperfusion. Propranolol (2 X 4 mg/kg) was intraperitoneally administered to guinea-pigs, daily for 21 days. It was perfused in vitro (1.10(-6) M) during the whole experiments. Propranolol decreased action potential duration in control conditions (p less than 0,05), precipitated the occurrence of inexcitability during severe ischemia (p less than 0,01) and improved the recovery of cellular excitability during reperfusion. Propranolol did not significantly affect the creatine-kinase leakage during ischemia and reperfusion.