Sotalol for ventricular tachyarrhythmias: Beta-blocking and class III contributions, and relative efficacy versus class I drugs after prior drug failure

In the Electrophysiologic Study Versus Electrocardiographic Monitoring (ESVEM) trial, d,l-sotalol was associated with a lower arrhythmia recurrence and mortality than class I antiarrhythmic drugs. To further evaluate the relative efficacy of d,l-sotalol compared with class I drugs, and to assess the relative importance of its class II (β-blocking) and class III effects, 6-year arrhythmia recurrence and mortality in patients receiving sotalol were compared with those in patients receiving class I drugs, subdivided according to whether they also received coadministered β blockers. Relative efficacy was also determined far sotalol and for class I drugs as stratified by the presence/absence of prior drug failure. Arrhythmia recurrence was lower for the 84 patients receiving sotalol than for patients given class I agents with (n = 28) (p = 0.008) or without (n = 184) (p = 0.001) a β blocker. Mortality was lower for patients taking sotalol than for those given a class I drug without a β blocker (p = 0.034), but similar (p = 0.835) if a β blocker was also administered. In contrast to class I drugs, which had lower efficacy rates when prior drug trials had failed, sotalol maintained its efficacy despite prior drug failures preceding or during the ESVEM trial. Both class II and III actions in the ESVEM trial were important to the clinical superiority of sotalol in the treatment of ventricular tachyarrhythmias.