Internal atrial defibrillation - a new treatment of postoperative atrial fibrillation

Atrial fibrillation (AF) commonly occurs following open heart surgery and may delay hospital discharge. Transthoracic electrical cardioversion is used when medical treatment is ineffective or associated with side effects. Traditionally general anesthesia is required. The aim of this multicenter study was to examine the feasibility and efficacy of low-energy atrial defibrillation using temporary epicardial defibrillation wire electrodes.

Epicardial stainless-steel defibrillation wire electrodes were sutured onto the left and right atrium during open heart surgery in 238 patients (age 64+/-9 years; 180 males). In case of postoperative AF R-wave synchronous low-energy shocks (0.6-10.8J) were applied to achieve cardioversion without anesthesia.

Implantation of the electrodes added 4.3+/-2.8 minutes to the operating time. During the hospital stay AF occurred in 47 patients (20%) at 2.1+/-1.3 days postoperatively. Fifty-one episodes of AF occurring in 44 patients were treated by atrial defibrillation. Primary success rate of cardioversion was 33/51 (65%). Early recurrence of AF (within 60 seconds after defibrillation) developed in 15 patients. Seven of these 15 patients were successfully defibrillated later on. Overall success rate was 40/51 (78%). The mean energy of successful shocks was 5.8+/-2.7 J. A mean of 2.3+/-1.7 shocks were applied per patient. The shocks were well tolerated by the patients in the absence of anesthesia. No complications were observed with shock application or with lead extraction.

Atrial defibrillation using temporary epicardial wire electrodes can be performed safely and effectively in patients following cardiac surgery. The shock energy required to restore sinus rhythm is low.