Effectiveness of Procaine Amide in Digitalis-Induced Ventricular Tachycardia. ∗

Abstract

Summary

Rapid intravenous administration of procaine amide was found effective in reverting ventricular tachycardia, produced in dogs by large doses of cardiac glycosides, to normal sinus rhythm. In most instances, the reversion was temporary and additional injections of procaine amide were necessary in order to maintain the normal rhythm. Such additional injections, repeated several times in these experiments, did not produce electrocardiographic signs of cumulative toxicity.

Although procaine amide effectively reverted ventricular tachycardia in the dog experiments, the same agent failed to increase the lethal dose as determined by limited “cat unit” studies. A similar relation was noted by Emerson in studies on procaine(6) and by Stanbury and Farah(7) in studies on magnesium.

The development of slow idioventricular rhythms and cardiac arrest in several experiments following procaine amide administration demonstrates a danger of drug termination of digitalis-induced ventricular tachycardia. As Gold(8) has emphasized, complete A-V heart block concomitantly produced by the digitalis may be masked in the electrocardiogram by the ventricular tachycardia and the abolition of the latter arrythmia by quinidine or other drugs may result in ventricular arrest.