A comparison of treatment of atrial fibrillation with low-energy intracardiac cardioversion and conventional external cardioversion

AIM: Low-energy (1 to 15 J), catheter-based intracardiac cardioversion was compared with transthoracic external cardioversion (360 J) in a prospective, cross-over clinical trial. METHODS AND RESULTS: In 187 consecutive patients with chronic atrial fibrillation, over a period of a mean of 10.0 +/- 7.3 (SD) months, 217 cardioversion attempts were made. Intracardiac shocks were randomly applied between two 6-F catheters located in either the right atrium and coronary sinus or between the right atrium and left pulmonary artery. When a cardioversion attempt with one method failed, the other method was implemented. After cardioversion, all patients were treated orally with sotalol with a mean daily dose of 174 +/- 54 mg. Internal cardioversion was more effective than external cardioversion (65/70 = 93% vs 92/117 = 79%, P < 0.01). The mean energy for successful cardioversion was 5.8 +/- 3.2 J for the internal and 313 +/- 71 J for the external cardioversion group. At a mean follow-up of 12.5 +/- 6.4 months, 48% (38%) of the patients treated with internal (external) cardioversion were in sinus rhythm (P < 0.05). In 22 of 25 patients in whom external cardioversion failed, sinus rhythm was restored with internal cardioversion at a mean energy of 6.5 +/- 3.0 J. Overweight patients had twice the risk of unsuccessful external cardioversion. CONCLUSIONS: Internal cardioversion is effective in restoring sinus rhythm. It might be indicated in patients in whom external cardioversion had failed or in whom external cardioversion is assumed to be difficult or even contraindicated.