Remodeling and Reverse-Remodeling of Left Atrium and Appendage After Catheter Ablation for Atrial Fibrillation

The processes of remodeling and reverse-remodeling of left atrial (LA) and LA appendage (LAA) after catheter ablation for atrial fibrillation (AF) are insufficiently evaluated. A total of 372 consecutive AF patients undergoing ablation procedure with contrast CT images and whose follow-up CT images were acquired after the procedure were enrolled. From those CT images, LA volume (LAV), LA emptying fraction (LAEF), LAA volume (LAAV), and LAAEF were measured. Mean age of patients was 70 years, and CHA₂DS₂-VASc score was 2.5 ± 1.7. Mean LAV, LAEF, LAAV, and LAAEF were 121.3 ml, 22.1%, 18.6 ml, and 23.5%, respectively. For patients with LA and LAA remodeling, nonparoxysmal AF (non-PAF) was more prevalent and strongly correlated with heart failure-related parameters. All types of remodeling were associated with recurrent postprocedure atrial tachyarrhythmias, and LAV emerged as an independent risk factor for recurrent tachyarrhythmias (adjusted hazard ratio 1.01, p = 0.02) in multivariable analysis. Follow-up CT images showed that LAV and LAAV significantly decreased, while LAEF and LAAEF significantly increased accompanied by a reduction in filling defects in the LAA. After the procedure, reverse-remodeling was prominent in non-PAF patients, while LAEF significantly decreased in PAF patients. The decrease in LAEF for PAF patients was significantly larger in those who received additional ablation beyond pulmonary vein isolation (PVI) than those who received PVI alone. On the other hand, in non-PAF patients, postprocedure LA reverse-remodeling was consistent regardless of ablation strategy, but significantly poor in those with recurrence. In conclusions, LA and LAA remodeling were more prevalent in non-PAF patients. LA and LAA reverse-remodeling after the ablation procedure were remarkable in non-PAF patients, especially those without recurrence. Meanwhile, LAEF decreased after the procedure in PAF patients, particularly in those who received additional ablation beyond PVI.