Long-term efficacy and safety of beta-adrenergic receptor antagonists for supraventricular tachycardia

Abstract

The efficacy and safety of nadolol and atenolol, 2 new long-acting β-adrenergic receptor antagonists, were evaluated in patients with recurrent supraventricular tachycardia (SVT). Intravenous and oral drug therapy was administered to patients with atrioventricular reentrant tachycardia and atrioventricular nodal reentrant tachycardia. Efficacy was judged on a short-term basis by programmed electrical stimulation and on a long-term basis by clinical parameters and serial ambulatory electrocardiographic recordings during long-term follow-up. In addition, the usefulness of programmed electrical stimulation to predict long-term efficacy was evaluated. Intravenous nadolol prevented induction of SVT in 6 of 8 (75%) patients with atrioventricular nodal reentrant tachycardia, and oral nadolol prevented induction of SVT in 5 of 6 (83%) responders to intravenous nadolol. No episodes of sustained SVT recurred in these 5 patients during follow-up. Intravenous nadolol also prevented induction of SVT in 2 of 17 (11%) patients with atrioventricular reentrant tachycardia. Both patients remained non-inducible during treatment with oral nadolol, and neither experienced recurrence of SVT during follow-up. Intravenous atenolol prevented induction of SVT in 5 of 6 (83%) patients with atrioventricular nodal reentrant tachycardia. Oral atenolol prevented induction of atrioventricular nodal reentrant tachycardia in 4 of 5 (80%) patients responding to intravenous atenolol, and none of these 4 patients experienced a clinical recurrence. Intravenous atenolol prevented induction of SVT in 1 of 4 (25%) patients with atrioventricular reentrant tachycardia. Oral atenolol prevented induction of SVT in this patient and the arrhythmia has not recurred during follow-up. During follow-up (1 to 37 months), drug tolerance and compliance have been excellent with a low incidence of adverse reactions (11%). Nadolol or atenolol alone is quite effective in the treatment of SVT due to atrioventricular nodal reentry (64%); each has limited efficacy in the treatment of SVT due to atrioventricular reentry (14%). Their efficacy is comparable to propranolol; however, nadolol and atenolol have the advantage of improved drug dosing schedules. Serial programmed electrical stimulation testing can be used to predict long-term efficacy of these agents in patients with SVT due to atrioventricular nodal and atrioventricular reentry.