Cardiac arrhythmias during anesthesia: A comparison of cyclopropane and pentothal-nitrous oxide-ether anesthesia

Abstract

Statistical data is given on the incidence of arrhythmias induced during 334 major surgical cases. Under cyclopropane anesthesia 62 per cent (70 out of 113 patients) had some type of arrhythmia. Six types of ventricular arrhythmias occurred eighty-five times in sixty-three cases. The multiple and multifocal ventricular premature contractions were the most frequent and dangerous arrhythmias; in this group of cases intravenous procaine for various ventricular or combined supraventricular and ventricular arrhythmias apparently benefited 93 per cent of the patients. Under pentothal-induced nitrous oxide-ether anesthesia 9 per cent (21 patients of 221) had some type of arrhythmia. Contrast this with 62 per cent arrhythmias in the cyclopropane group. Only eight patients had ventricular arrhythmias. The auricular arrhythmias were more common in this group but not worrisome. Intravenous procaine was effective in the ventricular arrhythmias in this group except in the case of cardiac arrest. A case of cardiac arrest occurred in each group and these are included as case reports. We believe that this study demonstrates a significant difference between the anesthetics in regard to their potentialities for causing serious disturbances of cardiac rhythm. This study also emphasizes the advantage of using the electrocardiograph in surgery 12 to evaluate better the effect of anesthetic agents on the cardiac mechanism.