A NEW STATISTICAL-METHOD FOR ASSESSING ANTIARRHYTHMIC DRUG EFFICACY AND A DRUG-INDUCED ARRHYTHMOGENIC EFFECT IN INDIVIDUAL PATIENTS

Abstract

Standards to define both antiarrhythmic drug efficacy and a drug-induced arrhytmogenic effect were developed. In 45 patients with frequent and complex ventricular tachyarrhythmias 3 continuous 24 h Holter recordings were performed. The spontaneous variability of ventricular premature beats and ventricular pairs was calculated using a new statistical method (transformation model). If 2 24 h Holter monitoring periods, 1 period before and the other with antiarrhythmic therapy, are compared, at least 75% reduction of ventricular premature beats and 90% reduction of ventricular pairs is necessary to be reasonably certain that a drug response rather than spontaneous arrhythmia reduction (P .ltoreq. 0.05) is being increased. Drug-induced aggravation can be assumed if ventricular premature beats and ventricular pairs have increased by more than 144% and 227%, respectively, (P .ltoreq. 0.05).