[What is the latest in anti-arrhythmia therapy?]

Author(s): Gloor HO

Affiliation(s): Klinik im Schachen, Aarau.

Publication date & source: 1991-11-23, Schweiz Med Wochenschr., 121(47):1711-4.

Publication type: English Abstract; Review

Ventricular premature beats are an independent risk factor for sudden cardiac death. Class Ic antiarrhythmic drugs suppress these premature contractions. The Cardiac Arrhythmia Suppression Trial (CAST-Trial) tested the hypothesis that the suppression of ventricular premature beats after myocardial infarction reduces the incidence of cardiac death. The results of treatment in this low risk group were, however, disappointing. Cardiac mortality (mortality related to arrhythmia and myocardial infarction) was higher in the group treated with flecainide or encainide than in the placebo group. After a treatment period of 10 months, 89 of 1498 patients had died, 63 (8.3%) of them in the flecainide/encainide and only 26 (3.5%) in the placebo-treated group. Drugs that increase the refractory period of a myocardial substrate are obviously more effective in suppressing cardiac death than drugs that delay conduction. In the Basel Antiarrhythmic Study of Infarct Survival (BASIS study) patients with complex ventricular arrhythmias after infarction were treated with low dose amiodarone (200 mg/day). After a follow-up period of 12 months, mortality was lower in the amiodarone treated group (5/98 patients, 5%) than in the group that received no antiarrhythmic treatment (15/114 patients, 13%). Amiodarone was also more beneficial than individual antiarrhythmic therapy (mortality 10/100 patients, 10%). In the past few years no new antiarrhythmic drugs have been registered in Switzerland. Our pathophysiological and clinical knowledge has, however, increased and we know that the asymptomatic patient with low grade ventricular ectopies after myocardial infarction need not be treated. However, if we decide to use antiarrhythmic drugs, strict quality control of the effects of the treatment is mandatory.(ABSTRACT TRUNCATED AT 250 WORDS)