Effect of glucagon on arrhythmias induced by coronary artery occlusion and ouabain in dogs.

The effect of glucagon in arrhythmias induced by coronary artery occlusion and ouabain was studied in dogs. Intravenous administration of glucagon (50 microgram/kg) to 6 dogs with more than 70% ectopic activity after coronary artery occlusion, resulted in significant (P less than 0.01) decrease in ectopics and increase in heart rate. Infusion of glucagon (2.5 microgram/kg/min) for 30 min caused complete elimination of ectopic activity during infusion period. In another series of 7 experiments, glucagon failed to abolish the ouabain-induced ectopic beats. In fact the hormone itself caused a significant (P less tha 0.01) increase in ectopic activity and heart rate. However, in 7 dogs with complete heart block produced after ouabain conversion to normal sinus rhythm was observed after glucagon.