An implantable atrial defibrillator successfully terminated 89% (8 of 9) of spontaneous atrial fibrillation episodes in three patients, with no ventricular proarrhythmia observed.
Case Report (n=3)
Does an implantable atrial defibrillator safely and effectively restore sinus rhythm in patients with drug-refractory paroxysmal AF?
Initial clinical experience demonstrates that an implantable atrial defibrillator is capable of accurate AF detection, R wave synchronization, and successful defibrillation without ventricular proarrhythmia in patients with paroxysmal AF.
Low energy biatrial shock is an effective means of restoring sinus rhythm in patients with atrial fibrillation (AF). Ventricular proarrhythmia is avoided provided that shocks are well synchronized to R waves that are not at closely coupled intervals or preceded by long-short cycles. Based on these principles, an implantable atrial defibrillator has been developed and was implanted in three patients with drug refractory paroxysmal AF. The device detects AF via an actively fixed right atrial and a self-retaining coronary sinus defibrillating leads, and delivers 3/3 ms biphasic shocks up to 300 V synchronized to the R wave. The mean implant threshold (ED50) was 195 V (1.8 J). and minimum voltage at conversion during follow-up assessments at 1, 3, and 6 months were 260 V, 2.5 J. 250 V, 2.3 J, and 300 V, 3.0 J respectively. Detection of AF was 100% specific and shocks were 100% synchronized, although only a proportion of synchronized R waves were considered suitable for shock delivery primarily because of closely coupled cycles. Three patients had 9 spontaneous AF episodes, 8/9 (89%) successfully defibrillated by shocks of 260-300 V. Sedation was not used in 4 out of 9 (45%) episodes. Backup ventricular pacing was initiated by the device in 6 out of (67%) episodes. One patient had more frequent AF after lead placement, which subsided after a change of medication. There was no ventricular proarrhythmia. It is concluded that an implantable atrial defibrillator is a viable therapy for selected patients with paroxysmal AF. The device is capable of accurate AF detection, R wave synchronization and ventricular support pacing after successful defibrillation of AF.
Lau et al. (Wed,) conducted a case report in Drug refractory paroxysmal atrial fibrillation (n=3). Implantable atrial defibrillator was evaluated on Successful defibrillation of spontaneous AF episodes. An implantable atrial defibrillator successfully terminated 89% (8 of 9) of spontaneous atrial fibrillation episodes in three patients, with no ventricular proarrhythmia observed.