A comparison of antiarrhythmic drugs for the suppression of ventricular ectopic depolarizations: a meta-analysis

This article reports the results of a meta-analysis of the effectiveness of antiarrhythmic drugs for the suppression of ventricular ectopic depolarizations. We analyzed 97 published articles that referred to a total of 27 drugs and contained data from 2989 patient-treatment trials; our goal was to determine the number of patients responding to therapy, defined as greater than or equal to 80% suppression of ventricular ectopic depolarizations. By means of logistic regression we tested the effect of 10 clinical and experimental variables on the likelihood of response to therapy. The likelihood of a drug response was significantly affected by the following six variables: increased by the use of dose titration (t = 3.59, p less than 0.0001), increased by the use of a higher daily dose (t = 3.21, p less than 0.0001), decreased by older age (t-2.67, p = 0.004), decreased by the use of blinding (t = -2.28, p = 0.011), increased by treating more male patients (t = 1.72, p = 0.043), and decreased by the presence of cardiovascular disease (t = -1.52, p = 0.064). Incorporating these six variables into our logistic regression model, we adjusted the response rate in each published study and calculated the mean response and standard error for each drug. Of the drugs tested in at least 100 patients, the most effective were amiodarone (estimated response rate 90%), encainide (80%), flecainide (79%), and propafenone (74%). Class IC drugs were significantly more effective than class IB and II drugs (p less than 0.05). With the exception of lorcainide and moricizine, class IC drugs were also more effective than class IA drugs (p less than 0.05). Amiodarone was significantly more effective than all drugs except encainide and flecainide (p less than 0.05). We found no significant differences among the response rates to class IA, IB, and II drugs. Whereas several patient and study characteristics affect the likelihood of response to antiarrhythmic drugs, class IC drugs and amiodarone are significantly more effective than other drugs in suppressing ventricular ectopic depolarizations.