The clinical use of diphenylhydantoin (Dilantin) in the treatment and prevention of cardiac arrhythmias

Abstract

The use of intravenous diphenylhydantoin (5 mg. per kilogram) in the treatment and prevention of cardiac arrhythmias was studied. In the treatment of arrhythmias caused by digitalis, diphenylhydantoin restored 6 of 11 atrial arrhythmias to sinus rhythm and 21 of 24 ventricular arrhythmias responded. In patients whose arrhythmias were not digitalis-induced, only one of 20 patients with atrial and 5 of 16 with ventricular arrhythmias responded. Diphenylhydantoin significantly improved the cardiac rhythm in 10 of 12 patients with ventricular arrhythmias which were unresponsive to procaine amide. In 12 patients, atrial or ventricular arrhythmias developed either during digitalization or maintenance digitalis. In these patients, diphenylhydantoin was given immediately prior to DC cardioversion. In all cases, DC countershock produced sinus rhythm with no immediate postshock arrhythmias. Diphenylhydantoin was given to 11 patients prior to cyclopropane anesthesia. Ten of the 11 patients had no arrhythmias during the anesthetic, whereas only one of 9 patients in the control group was free of arrhythmias. Diphenylhydantoin restored sinus rhythm in 8 patients who developed ventricular arrhythmias during the administration of various anesthetics, but had no effect in 2 patients with atrial arrhythmias. Side effects due to diphenylhydantoin were minor and transient and no deaths occurred. It is concluded that with slow administration and careful electrocardiographic and blood pressure monitoring, diphenylhydantoin is a safe and valuable agent in both the treatment and prevention of cardiac arrhythmias.