Absence of relationship between antiarrhythmic effects of antidepressant drugs and lipid peroxidation

Tricyclic antidepressant drugs may affect the cardiovascular system, principally in patients with preexisting cardiac disease. The present study was undertaken to compare the effects of amitriptyline and mianserin with those of tianeptine, an atypical tricyclic antidepressant drug, in rat isolated working heart subjected to a local myocardial ischemia. Coronary, aortic and cardiac flows, and heart rate remained stable during the whole preischemic period in control hearts. Ligation of the left main coronary artery induced a 50% decrease in coronary, aortic and cardiac flow without any change in heart rate. Reperfusion was characterized by the occurrence of ventricular arrhythmias (ventricular tachycardia and ventricular fibrillation) and by a marked reduction in cardiodynamic parameters. Amitriptyline (1 and 10 mumol/l) and mianserin (1 and 10 mumol/l) exhibited an antiarrhythmic activity against reperfusion arrhythmias. Tianeptine (1 and 10 mumol/l) was not able to reduce the incidence of reperfusion arrhythmias. Although tianeptine did not change heart rate, mianserin and amitriptyline induced a bradycardia. Mianserin and amitriptyline improved the cardiac recovery of cardiac function during reperfusion. The cardiodynamic parameters (coronary, aortic and cardiac flows) were not altered by tianeptine during the preischemic period. Furthermore, these parameters were similar to those observed in the control group both during ischemia and reperfusion. The beneficial effects of amitriptyline and mianserin observed in the setting of myocardial reperfusion were not associated with a reduced lipoperoxidation investigated by using an in vitro model in the presence or absence of a free-radical-generating system. The results of the present study indicate that the pronounced antiarrhythmic activities of mianserin and amitriptyline cannot be explained by an antiperoxidative action of these drugs.