Propafenone in the treatment of patients with malignant ventricular tachyarrhythmias.

This study was conducted to determine the value of propafenone in patients with resistant malignant ventricular arrhythmias. Forty patients with either sustained ventricular tachycardia (n = 34) or primary ventricular fibrillation (n = 6), who had failed an average of four previous drug trials, were studied prospectively. The mean age was 68 years. Thirty-five had had a previous infarction, and left ventricular ejection fractions ranged from 14 to 57% (mean 36%). Noninvasive evaluation, consisting of ambulatory monitoring and exercise testing, was used to guide therapy in 12 patients, and invasive electrophysiological study was employed in the other 28. The initial daily dose was 450 mg, and electrocardiographic intervals were used to titrate the dose upward to a maximum of 900 mg per day or to tolerance. Five of the 12 noninvasively studied patients had complete abolition of ventricular tachycardia salvos. Only five of the 28 patients were rendered noninducible, but another four had adequate rate slowing with good hemodynamic tolerance of their arrhythmias. In an additional six patients, the addition of a second antiarrhythmic drug produced supplemental rate slowing. Side effects occurred in 30 patients and necessitated drug withdrawal in 13. The most serious adverse effects were congestive heart failure (in eight patients, and three withdrawn) and proarrhythmia (in four patients, and all withdrawn). The 20 patients with an adequate response were discharged on propafenone. During a mean follow-up of 12 months, there have been three cardiac deaths, one of which was sudden, and three recurrences of sustained ventricular tachycardia. Efficacy and side effects did not correlate with dose or degree of increase in electrocardiographic intervals.(ABSTRACT TRUNCATED AT 250 WORDS)