EFFECT OF ELECTRODE POSITION ON OUTCOME OF LOW-ENERGY INTRACARDIAC CARDIOVERSION OF ATRIAL-FIBRILLATION

The aim of this study was to evaluate the new method of low-energy, ca theter-based intracardiac cardioversion in patients with chronic atria l fibrillation (AF) and to compare 2 different lead positions. Accordi ngly, we prospectively studied 80 consecutive patients with chronic AF (9.8 +/- 7.9 months) who were randomly assigned to undergo internal c ardioversion either via defibrillation electrodes placed in the right atrium and coronary sinus (coronary sinus group) or via defibrillation electrodes placed in the right atrium and left pulmonary artery (pulm onary artery group). Intracardiac shocks were delivered by an external defibrillator synchronized to the QRS complex. After conversion, all patients were treated orally with sotalol (mean daily dose, 189 +/- 63 mg/day). For conversion to sinus rhythm, the overall mean energy requ irement was 5.6 +/- 3.1 J. In the coronary sinus group, cardioversion was achieved in 35 of 38 patients at a mean energy level of 4.1 +/- 2. 3 J (range 1.0 to 9.9), and in the pulmonary artery group in 39 of 42 patients with 7.2 +/- 3.1 J (range 2.5 to 14.8). Although there was no difference with regard to success rate, the energy differed significa ntly between the 2 groups (p < 0.01). Mean lead impedance was 56.4 +/- 7.0 Ohm and 54.6 +/- 8.4 Ohm, respectively (p = NS). No serious compl ications were observed in either lead group. At a mean followup of 14. 2 +/- 7.0 months, 54% and 56%, respectively, of patients who had been converted successfully remained in sinus rhythm. Thus, low-energy biph asic shocks delivered between the right atrium and coronary sinus or p ulmonary artery are equally effective for cardioversion of patients wi th chronic AF. The energy requirements for conversion from a pulmonary artery electrode position are higher than for the coronary sinus posi tion. (C) 1997 by Excerpta Medica, Inc.