Effect of the implantable atrial defibrillator on the natural history of atrial fibrillation

Implantable Atrial Defibrillator. Introduction: The purpose of our study wa s to evaluate the effect of repeated cardioversion with an implantable atri al defibrillator on the clinical outcome of patients with atrial fibrillati on. Methods and Results: The effects of the implantable atrial defibrillator on the total duration of atrial fibrillation, number of atrial fibrillation r ecurrences, and left atrial size were evaluated prospectively in 16 patient s with atrial fibrillation (13 men and 3 women; mean age 58 +/- 11 Sears). Seven patients had no cardiovascular disease, 5 patients had hypertension, 3 patients had coronary heart disease, and 1 patient had congenital heart d isease. Eight patients had paroxysmal atrial fibrillation for a mean durati on of 80 +/- 61 months, and eight patients had persistent atrial fibrillati on for a mean duration of 68 +/- 119 months. Except for one patient who rec eived digoxin throughout the study, all patients received the same Class I or III antiarrhythmic agent throughout the study. The implantable atrial de fibrillator successfully converted 50 (93%) of 54 spontaneous episodes of a trial fibrillation in 12 patients. During the initial 3 months of clinical follow-up, the atrial defibrillator documented 261 +/- 270 hours of atrial fibrillation compared with 126 +/- 172 hours (P = 0.01) during the subseque nt 3 months. The left atrial size decreased from 4.4 +/- 0.7 cm at the time of atrial defibrillator implantation to 4.1 +/- 0.6 cm (P = 0.02) 6 months later. The number of atrial fibrillation recurrences did not change. These findings were observed in the absence of changes in drug therapy. No compl ications were observed. Conclusion: Restoration and maintenance of sinus rhythm in patients with at rial fibrillation by repeated cardioversion,vith an implantable atrial defi brillator was associated with a reduction in the total arrhythmia duration and a reduction in left atrial size. These results suggest that maintenance of sinus rhythm with the atrial defibrillator may reverse the remodeling p rocess associated with atrial fibrillation.