Antiarrhythmic effect of magnesium sulfate against occlusion-induced arrhythmias

The antiarrhythmic effect of magnesium sulfate (Mg) as well as the hemodyna mics were studied using the coronary ligation and reperfusion models in rat s. In the study on coronary ligation arrhythmia, i.v. administration of Mg (0. 6, 2, 6, 20 and 60 mu mol) was conducted at 5 min after coronary ligation. Mg had an action to decrease the total number of premature ventricular cont raction (PVC), the duration of ventricular tachycardia (VT), the frequency of VT and ventricular fibrillation (Vf) and the mortality ratio for 30 min after coronary ligation. In the 6-60 mu mol groups, significant antiarrhyth mic action (p < 0.01 vs. control) was attained. In the study on reperfusion arrhythmia, i.v. administration of Mg (20, 60 a nd 200 mu mol) was conducted at 4 min after coronary ligation, and at 1 min after ligation, the coronary artery was reperfused. Mg had an action to de crease the frequency of Vf, the mortality ratio and the duration of VT and Vf and to extend the interval between the initiation of reperfusion and the occurrence of VT and Vf for 10 min after reperfusion. In the 200 mu mol gr oup, significant antiarrhythmic action (p < 0.05 vs. control) was attained. Administration of Mg decreased the heart rate and blood pressure. We concluded that Mg can control myocardial ischemia-induced and reperfusio n-induced arrhythmia and that sudden cardiac death which occurs as a result of arrhythmia can be prevented.