Differing Electrophysiological Effects of Various Antiarrhythmic Drugs on the Cardiac Chamber in Atrial Fibrillation

Jang, Su Young; Cho, Jeong Gwan; Jung, Hyung Ki; Ki, Won Ju; Lee, Kyoung Jin; Ko, Jum Suk; Lee, Min Goo; Park, Keun Ho; Sim, Doo Sun; Yoon, Nam Sik; Yoon, Hyun Ju; Hong, Young Joon; Park, Hyung Wook; Kim, Ju Han; Ahn, Youngkeun; Jeong, Myung Ho; Park, Jong Chun; Kang, Jung Chaee

Abstract

BACKGROUND/AIMS
Long-term antiarrhythmic drug therapy remains the principal approach for suppressing atrial fibrillation (AF) and maintaining sinus rhythm. In this study, we examined the differing electrophysiological effects of various antiarrhythmic drugs on the cardiac chamber and atrial selectivity in patients with AF.
METHODS
We analyzed 134 patients (60.4 +/- 12.5 years, M:F = 1.14:1) who were administered a single antiarrhythmic agent for AF over 6 months: amiodarone (group A), flecainide (group F), or propafenone (group P). The P wave, QRS complex duration and dispersion, and QT interval and its dispersion were evaluated using a standard 12-lead electrocardiogram.
RESULTS
There was no significant difference in age, gender ratio, or associated diseases among the three groups. In group A, Pmax, Pmin, P dispersion, QRSmax, QRSmin, and QRS dispersion were shorter than in groups F and P, whereas Pmax/QRSmax was the highest in group A (A = 1.2, F = 0.9, P = 1.0; p < 0.01). QTcmax and QTcmin were longer in group A, whereas QTc dispersion and the QT peak to end (A = 13.3 +/- 11.2, F = 30.7 +/- 24.9, P = 31.8 +/- 21.6; p < 0.01) were shorter in group A than in the other groups.
CONCLUSIONS
Amiodarone had a weaker, but more selective, inhibitory effect on intra-atrial conduction, and inhibited ventricular repolarization more effectively and homogenously than flecainide or propafenone. These differing electrophysiological effects may contribute to the superior effectiveness and safety of amiodarone over flecainide or propafenone.