Efficacy and safety of out-of-hospital self-administered single-dose oral drug treatment in the management of infrequent, well-tolerated paroxysmal supraventricular tachycardia

OBJECTIVES: We tested the efficacy of two drug treatments, flecainide (F) and the combination of diltiazem and propranolol (D/P), administered as a single oral dose for termination of the arrhythmic episodes. BACKGROUND: Both prophylactic drug therapy and catheter ablation are questionable as first-line treatments in patients with infrequent and well-tolerated episodes of paroxysmal supraventricular tachycardia (SVT). METHODS: Among 42 eligible patients (13% of all screened for SVT) with infrequent (≤5/year), well-tolerated and long-lasting episodes, 37 were enrolled and 33 had SVT inducible during electrophysiological study. In the latter, three treatments (placebo, F, and D/P) were administered in a random order 5 min after SVT induction on three different days. RESULTS: Conversion to sinus rhythm occurred within 2 h in 52%, 61%, and 94% of patients on placebo, F and D/P, respectively (p <0.001). The conversion time was shorter after D/P (32 ± 22 min) than after placebo (77 ± 42 min, p <0.001) or F (74 ± 37 min, p <0.001). Four patients (1 placebo, 1 D/P, and 2 F) had hypotension and four (3 D/P and 1 F) a sinus rate