Initial experience with single lead intracardial cardioversion for refractory atrial fibrillation

Chronic atrial fibrillation (AF) is a common arrhythmia, associated with a substantial morbidity (thromboemboli, worsening left ventricular function). Established therapy for pharmacological refractory AF is high-energy trans-thoracic electric cardioversion (TTCV), but this strategy is ineffective for 10-30% of the patients. The purpose of the present study is to establish the safety and efficacy of low-energy intracardiac cardioversion (ICCV) with a relatively new balloon-guided single-catheter system with dual chamber pacing possibility for this group of patients.

Patients in whom an attempt to restore sinus rhythm (SR) by TTCV under antiarrhythmic therapy failed were eligible for the study. For the ICCV-attempt, a single flow-guided atrial cardioversion catheter was used. Low-energy biphasic shocks of increasing energy (6-15 J) were delivered, if necessary in combination with intravenous amiodarone, until SR was restored. In case of early recurrence of AF, another attempt was made with immediate post-shock overdrive pacing (AOO) in order to suppress premature atrial activity.

Initially, 14 of the 16 treated patients (90%) were converted to SR successfully. In eight patients additional amiodarone i.v. was administered and in six patients atrial overpacing was used after ICCV. In seven and five patients, respectively, these strategies were successful. Long-term follow-up (1-3 months) showed that in nine patients (56%) SR was preserved; eight of them on oral amiodarone. No adverse events were seen during the procedure and follow-up, especially no bleedings, despite puncturing under adequate anticoagulation therapy.

ICCV using a single atrial cardioversion catheter is a safe and effective method to restore SR in patients in whom TTCV failed previously. Long-term follow-up of this procedure is comparable to that of other studies. Results are influenced by antiarrhythmic drug therapy, compliance and patient selection.