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) an d the combination of diltiazen and propranolol (D/P), administered as a sin gle oral does for termination of the arrhythmic episodes. BACKGROUND Both prophylactic drug therapy and catheter ablation are questio nable as first-line treatments in patients with infrequent and well-tolerat ed episodes of paroxysmal supraventricular tachycardia (SVT). METHODS Among 42 eligible patients (13% of all screened for SVT) with infre quent (less than or equal to5/year), well-tolerated and long-lasting episod es, 37 were enrolled and 33 had SVT inducible during electrophysiological s tudy. In the latter, three treatments (placebo, F, and D/P) were administer ed ina 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 conversio n time was shorter after D/P (32 +/- 22 min) than after placebo (77 +/- 42 min, p < 0.001) of 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 <50 b eats/min following SVT interruption. Patients were discharged on a single o ral patients were discharged on D/P and five on F. During 17 +/- 12 months follow-up, the treatment was successful in 81% of D/P patients and in 80% o f F patients, as all the arrhythmic episodes were interrupted out-of-hospit al within 2 h. In the remaining patients, a failure occurred during one or more episodes because of drug ineffectiveness or drug unavailability. One p atient had syncope after D/P ingestion. during follow-up, the percentage of patients calling for emergency room assistance was significantly reduced a s compared to the year before enrollment (9% vs. 100%, p < 0.0001). CONCLUSIONS The episodic treatment with oral D/P and F, as assessed during acute testing, appears effective int he management of selected patients wit h SVT. This therapeutic strategy minimizes the need for emergency room admi ssions during tachycardia recurrences. (C) 2001 by the American College of Cardiology.