Combined anti-arrhythmic therapy with class 1 and class 3 drugs

This study was designed to investigate the differences in efficacy between 3 different combinations of amiodarone and a class 1 anti-arrhythmic drug (one from each class). The purpose was to determine whether the known differing electrophysiological properties of class 1 drugs result in any particular one making a superior combination with the class 3 drug amiodarone. Eight patients were studied in a randomized single blind cross-over trial. Amiodarone and flecainide proved to be the superior combination producing a significantly greater reduction in mean ectopic counts/24 hours than the amiodarone/mexilitene combination (1,286 vs 3,243; P less than 0.05) or the amiodarone/disopyramide combination (3,795; P less than 0.05). All 3 combinations reduced mean ectopic counts from the baseline value (8,729), but this was only significant for amiodarone/flecainide (P less than 0.01) and amiodarone/mexilitene (P less than 0.05). In addition the amiodarone/flecainide combination produced a significant reduction in complex forms of arrhythmia with ventricular tachycardia abolished in all cases, which was not achieved by any other combination.