Abstract 1841: Left Atrial Volume From 3-dimensional CT Correlates With Atrial Fibrillation Recurrence Following Ablation
Objective: Recurrence of atrial fibrillation (AF) following ablation is common, and further delineation of prognostic markers is needed. We investigated whether LA volume, which can be accurately obtained from 3-dimensional CT, correlates with AF recurrence.
Methods: 73 consecutive patients (52 paroxysmal, 21 persistent) undergoing AF ablation were studied. Follow-up was for a minimum of 9 months, and success was determined by 12-lead EKG and lack of symptoms (unless symptoms proven not AF by Holter). LA volume was calculated by summation of axial CT slices. The left atrial appendage was measured separately.
Results: Overall procedure success was 66% including 11 (15%) who had repeat ablations and 9 (12%) who were on antiarrhythmics. Pulmonary vein isolation was performed in all, with additional linear ablation in 44 (60%). The mean (95% CI) LA volume for those with recurrent AF was 119 cc (104, 135) versus 98 cc (90, 106) for no recurrence (p=0.01, rank sum). Wide variation in LA volume was noted in both groups (see box plot). For those patients with a volume >135cc (n=11), 9 (82%) had recurrent AF. No correlation existed between recurrence and type of AF or ablation strategy. Patients who had received a linear ablation had a larger mean LA volume than those who had not (111 cc vs. 97 cc, p=0.03, rank sum). LA appendage volume was not associated with recurrence.
Conclusion: LA volume variation is large in both those with and without successful AF ablations. Mean LA volume is significantly larger in those with recurrent AF. Patients with LA volumes >135 cc are very likely to experience recurrent AF. More aggressive ablation strategies may be required in patients with large LA volumes.