Double-Blind Crossover Study of Diphenylhydantoin in Angina Pectoris

¹ Cardiac Department, Stobhill Hospital, Glasgow, Scotland

A double-blind crossover study of diphenylhydantoin (DPH) was performed in 16 patients with typical symptoms of angina pectoris. Group A (nine patients) had objective evidence of myocardial ischemia (ST depression in V₅ on exercise of 1 mm or more) and at least five angina pains per week during the double-blind placebo period. Group B (seven patients) lacked positive exercise tests or had less than five pains per week on placebo. Group A patients showed a clinically and statistically significant reduction in the frequency and duration of anginal episodes but performed significantly less exercise during two-step testing. No significant changes were noted in ischemic ST depression. Similar results were obtained in group B patients. The results suggest that the symptomatic improvement in angina pectoris could be related to DPH-induced curtailment of physical activity. In view of the increasing use of DPH as an antiarrhythmic agent in patients with ischemic heart disease, further evaluation of the symptomatic and hemodynamic effects of oral DPH is required.