Treatment of paroxysmal supraventricular tachycardia with oral diltiazem

Symptomatic paroxysmal supraventricular tachycardia is a troubling arrhythmia for many patients. To test the efficacy of oral diltiazem to reduce symptomatic recurrences of paroxysmal supraventricular tachycardia, we enrolled 17 patients in a double‐blind, placebo‐controlled crossover study. Sixteen of 17 patients completed a dose‐ranging phase and were entered into the randomized phase. Although the time to first recurrence of tachycardia was slightly longer when patients took diltiazem, the difference was not significant ( p = 0.15). The hazard ratio of the time to first recurrence on placebo compared with oral diltiazem was 2.7 (95% confidence interval, 0.8 to 9.1). Of the patients who had a recurrence of tachycardia in both treatment periods, the median reduction in heart rate in patients receiving diltiazem was 20 beats/min. ( p < 0.01; 95% confidence interval, 6 to 42). Clinical Pharmacology and Therapeutics (1992) 51 , 562–565; doi: 10.1038/clpt.1992.63