Could successful cryoballoon ablation of paroxysmal atrial fibrillation prevent progressive left atrial remodeling?

BACKGROUND Radiofrequency catheter ablation of atrial fibrillation (AF) has been proved to be effective and to prevent progressive left atrial (LA) remodeling. Cryoballoon catheter ablation (CCA), using a different energy source, was developed to simplify the ablation procedure. Our hypothesis was that successful CCA can also prevent progressive LA remodeling. METHODS 36 patients selected for their first CCA because of nonvalvular paroxysmal AF had echocardiography before and 3, 6 and 12 months after CCA. LA diameters, volumes (LAV) and LA volume index (LAVI) were evaluated. LA function was assessed by: early diastolic velocities of the mitral annulus (Aa(sept), Aa(lat)), LA filling fraction (LAFF), LA emptying fraction (LAEF) and the systolic fraction of pulmonary venous flow (PVSF). Detailed left ventricular diastolic function assessment was also performed. RESULTS Excluding recurrences in the first 3-month blanking period, the clinical success rate was 64%. During one-year of follow-up, recurrent atrial arrhythmia was found in 21 patients (58%). In the recurrent group at 12 months after ablation, minimal LAV (38 ± 19 to 44 ± 20 ml; p < 0.05), maximal LAV (73 ± 23 to 81 ± 24 ml; p < 0.05), LAVI (35 ± 10 to 39 ± 11 ml/m2; p = 0.01) and the maximal LA longitudinal diameter (55 ± 5 to 59 ± 6 mm; p < 0.01) had all increased. PVSF (58 ± 9 to 50 ± 10%; p = 0.01) and LAFF (36 ± 7 to 33 ± 8%; p = 0.03) had decreased. In contrast, after successful cryoballoon ablation LA size had not increased and LA function had not declined. In the recurrent group LAEF was significantly lower at baseline and at follow-up visits. CONCLUSIONS In patients whose paroxysmal atrial fibrillation recurred within one year after cryoballoon catheter ablation left atrial size had increased and left atrial function had declined. In contrast, successful cryoballoon catheter ablation prevented progressive left atrial remodeling.