[The effect of flecainide on 2 hour occlusion-induced myocardial damages in dog].

: This study was designed to clarify whether or not flecainide have cardioprotective effect on ischemic myocardium. Nineteen dogs anesthetized and subjected to 2 h coronary occlusion, were divided into 2 groups. In the control group, physiological saline was infused, and in the flecainide group, 2 mg/kg of flecainide acetate and followed by 100 micrograms/kg/min continuous infusion. To assess the cardioprotective effect, mitochondrial function and lysosomal enzyme activities were measured. Two hours after occlusion, mitochondria were prepared from both ischemic and non-ischemic areas in each group, and their function (respiratory control index, and the rate of oxygen consumption in state III respiration) were measured polarographically with succinate as substrate. Fractionation of myocardial tissue from both non-ischemic and ischemic areas was performed according to the method of Weglicki et al, and the activities of lysosomal enzymes (N-acetyl-beta-glucosaminidase, and beta-glucuronidase) were measured. In the control group, mitochondrial dysfunction and leakage of lysosomal enzymes induced by 2 h occlusion were observed. On the contrary, administration of flecainide maintained significantly mitochondrial function, and prevented significantly leakage of lysosomal enzymes. These results indicated that flecainide had cardioprotective effect as well as antiarrhythmic effects in ischemic myocardium.