Efficacy of flecainide, sotalol, and verapamil in the treatment of right ventricular tachycardia in patients without overt cardiac abnormality

Abstract

Objective: A comparison of the efficacy of verapamil, sotalol, and flecainide to suppress right ventricular tachycardia (VT) in patients with a clinically normal heart.

Design: Patients underwent treatment serially with verapamil (360 mg daily), sotalol (240 or 320 mg daily), and flecainide (200 or 300 mg daily), (the larger dose was for patients heavier than 80 kg) to suppress tachycardia. Each drug was given orally for five half lives before testing.

Patients: 23 patients with right VT associated with a clinically normal heart were studied.

Outcome measures: The effects of drug treatment were examined by the number of ventricular events on 24 hour Holter monitoring, and the ability of tachycardia to be induced by treadmill exercise testing (Bruce protocol) and programmed ventricular stimulation (Wellens protocol), compared with drug free baseline tests.

Setting: Patients were studied in a tertiary referral centre.

Results: All three drugs suppressed ventricular salvos (> 3, < 5 consecutive ventricular premature contractions) (p < 0.01) and VT (p < 0.05) on Holter monitoring and did not differ statistically in effect. Exercise induced VT was also suppressed by all three drugs (p < 0.01), and of these sotalol was the most effective although this was not statistically significant (14/23 inducible when drug free, 4/23 on flecainide, 2/23 on sotalol, 5/23 on verapamil). Sustained and non-sustained VT induced by programmed stimulation was also suppressed by the three drugs (p < 0.01) and again sotalol was the best of these though the differences did not achieve statistical significance (17/23 inducible when drug free, 4/17 on flecainide, 2/17 on sotalol, and 6/17 on verapamil). Proarrhythmic effects of drugs were found in a few patients. There was no difference in the efficacy of the drugs in patients with histological abnormalities of the myocardium when compared with those of normal histology.

Conclusions: Ventricular tachycardia associated with a clinically normal heart can be suppressed by flecainide, sotalol, or verapamil. In individual patients sotalol was the most frequently effective drug (effective in > 89% of patients) and is a suitable choice for first line treatment.