Impact of volume reduction in giant left atrium during surgical ablation of atrial fibrillation

Abstract

Background: An enlarged left atrium (LA) is a well-known risk factor for ablation failure of atrial fibrillation (AF). We analyzed the result of concomitant AF ablation in patients with a giant LA and evaluated the effect of LA volume reduction.

Methods: Between 2000 and 2011, 116 patients with a giant LA (antero-posterior dimension ≥70 mm) who underwent surgical AF ablation during MV surgery were retrospectively reviewed. Among these, 28 patients received aggressive LA volume reduction procedure (reduction group) while the other 88 patients received the surgery without LA volume reduction (non-reduction group). Mean follow-up duration was 6.8±3.0 years.

Results: Aortic clamping and cardio-pulmonary bypass times were significantly longer in reduction group than non-reduction group (P<0.001 and 0.025, respectively). There were no significant differences in early mortality rates (3.7% vs. 5.7%, P>0.99) and major complication rates. Rates of freedom from AF at 1, 3 and 5 years were 84.2%, 74.3% and 54.5%, respectively in reduction group and 49.0%, 33.2% and 28.4%, respectively in non-reduction group (P=0.013). Multivariable analysis revealed severe pulmonary hypertension as an independent risk factor for AF recurrence (HR, 15.9; 95% CI, 1.69–149.54, P=0.015) while LA volume reduction (HR, 0.50; 95% CI, 0.28–0.89, P=0.018) and the use of cryoablation instead of radiofrequency (HR, 0.11; 95% CI, 0.01–0.95, P=0.045) were found to be protective against AF recurrence.

Conclusions: Aggressive LA volume reduction was found to improve rhythm outcomes in patients with a giant LA undergoing surgical AF ablation.