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Comparative Study of the Antiarrhythmic Efficacy of Mexiletine and Disopyramide in Patients with Chronic Ventricular Arrhythmias

1982; Lippincott Williams & Wilkins; Volume: 4; Issue: 2 Linguagem: Inglês

10.1097/00005344-198203000-00017

1533-4023

Günter Breithardt, L Seipel, Jörg Lersmacher, R.-R. Abendroth,

Atrial Fibrillation Management and Outcomes

Summary In 15 hospitalized patients with chronic ventricular arrhythmias, the effect of oral disopyramide 600 mg per day and mexiletine 600 mg per day was studied using a single-blind, randomized, crossover protocol and 24-h tape recordings with a special purpose computer system. There was no significant difference in the incidence of single and complex ventricular arrhythmias during two control periods. Disopyramide decreased the median number of ventricular ectopic beats by 72% (range: minus 9.5 to minus 99.4%) (p ≤ 0.01). The median decrease in the incidence of ventricular couplets and salvoes was minus 98% (range: minus 23.7 to minus 100%) (p ≤ 0.01), and the decrease was greater than 80% in 13 patients. In six patients, ventricular couplets and salvoes were totally suppressed. During treatment with mexiletine, the number of ventricular ectopic beats decreased by a median of 25% (range: plus 142.2 to minus 99.6%) (p ≤ 0.01). The median decrease in ventricular couplets and salvoes was 80% (range plus 4088 to minus 100%) (p ≤ 0.05), and the decrease was greater than 50% in 13 patients and greater than 80% in 8 patients. In seven patients, an increase in dosage from 600 to 1000 mg augmented the effects of mexiletine on ventricular ectopic beats (from a median reduction of 22% to 82%) and on complex ventricular arrhythmias (from a median reduction of 88% to 97%). On the basis of individual patient data, the observed percentage reduction exceeded the statistically necessary one in 14 of 15 patients on disopyramide and in 9 of 15 patients on mexiletine (600 mg per day). In the subgroup of patients receiving 600 and 1,000 mg per day of mexiletine, the statistically significant reduction was reached in three out of seven patients after 600 mg and in six out of seven patients after 1,000 mg per day. No complication occurred in any patient. We conclude that at daily dosages of 600 mg, disopyramide is more effective than mexiletine for suppressing chronic ventricular arrhythmias, but that this difference disappears when mexiletine dosage is raised to 1 g per day.