ABSTRACT
Objectives: This study aims to analyze the relationship between late gadolinium enhancement cardiac magnetic resonance imaging (LGE-cMRI) detected scar formation of circumferential pulmonary vein and recurrence rate after catheter ablation in patients with atrial fibrillation, and to compare the efficacy of the single-step cryoballoon ablation with the point-by-point radiofrequency current ablation. Methods: A total of 56 patients with nonvalvular atrial fibrillation who underwent catheter ablation from July 2014 to December 2016 in Fujian Provincial Hospital were enrolled in this study. Among them, 27 patients underwent radiofrequency ablation (RFA), and 29 cases underwent cryoballoon ablation (CBA). Scar formation of circumferential pulmonary vein was detected by LGE-cMRI in all patients at 3 months after ablation. All patients were monitored by telephone or outpatient follow-up (patients complaint, ECG or 24-hour Holter, etc.) at 6 months post ablation. Recurrent atrial tachyarrhythmias were defined as ≥ 30 seconds AF, atrial flutter, or atrial tachycardia. Results: AF recurrence was defined in 13 (23.21%) patients. The ratio of scar formation in circumferential pulmonary vein was significantly lower in recurrence patients than that in the non-recurrent patients ([63.23±5.86]% vs [79.95±7.47]%, P<0.001). The ratio of scar formation in each pulmonary vein of 56 patients was as follows: (76.80±11.60)% in the left superior pulmonary vein, (78.90±10.64)% in the left inferior pulmonary vein, (83.35±9.44)% in the right superior pulmonary vein (P<0.05 vs the left superior pulmonary vein), which was significantly lower in the right inferior pulmonary vein (66.13±13.44)% than above veins (all P<0.05). The ratio of scar formation of all four pulmonary vein was significantly lower in recurrence patients than in the non-recurrent patients, especially in left superior pulmonary vein ([61.19±4.89]% vs [81.52±8.43]%) and the right lower pulmonary vein ([52.47±7.62] % vs [70.26±12.03]%), both P<0.001.Univariate analysis showed that the recurrence rate , the total ratio of scar formation in circumferential pulmonary vein and the ratio of scar formation in recurrence patients were similar between the CBA group and the RFA group. Conclusions: Lower circumferential pulmonary vein scar is associated with higher recurrence rate post catheter ablation in atrial fibrillation patients. The scar formation ratio is low in the right inferior pulmonary vein and the left superior pulmonary vein. The circumferential pulmonary veins scar after cryoablation and radiofrequency catheter ablation is equivalent, indicating the pulmonary vein isolation efficacy of the two procedual methods is comparable.