Thickening of the Left Atrial Wall Shortly After Radiofrequency Ablation Predicts Early Recurrence of Atrial Fibrillation

BACKGROUND: Inflammatory responses following atrial fibrillation (AF) ablation may aggravate arrhythmogenic activity and cause an early recurrence of AF (ERAF). METHODS AND RESULTS: In 56 patients who underwent circumferential pulmonary vein ablation (CPVA) for paroxysmal AF, cardiovascular magnetic resonance imaging (CMRI) was evaluated in 5 subdivided left atrial (LA) regions before the CPVA and at 1 day and 1 month after. At a mean of 7+/-10 days after the CPVA, 23 patients (41%) developed 1 or more episodes of AF (ERAF group), while 33 patients (59%) remained free from AF during the first month of follow up (no-ERAF group). LA wall thickness increased 1 day after the CPVA in both groups, as demonstrated by high T2-weighted signal. The LA roof thickness and its increase, however, were greater in the ERAF group than in the no-ERAF group (P<0.05). Regions of delayed enhancement (DE) were also frequently detected in both groups, but the total number of DE regions did not differ between the 2 groups. The thickening of the LA wall associated with a high T2-weighted signal resolved within 1 month. No significant difference between the 2 groups was found in any of the CMRI parameters before or 1 month after CPVA. CONCLUSIONS: Thickening of the LA roof shortly after CPVA may predict an ERAF.