Incidence of Atrial Fibrosis in Non-Valvular Atrial Fibrillation Patients and its Impact on Recurrence after Pulmonary Vein Antral Isolation

BACKGROUND: Atrial fibrillation (AF) is the most common sustained arrhythmia; it affects 1%-2% of the general population [1]. Many studies demonstrated an association between atrial fibrosis and AF [2]. There is increasing evidence that even in patients with lone AF; the AF is an arrhythmic manifestation of a structural atrial disease which has been described as fibrotic atrial cardiomyopathy [3]. It is unknown whether the presence of atrial fibrosis has any impact on post pulmonary vein antrum isolation outcome. PURPOSE OF THE STUDY: This study aims to determine the incidence of atrial fibrosis in patients with non-valvular AF and its impact on recurrence after pulmonary vein antrum isolation. PATIENTS AND METHODS: This study included twenty eight consecutive patients referred for first-time pulmonary vein antrum isolation for the treatment of symptomatic recurrent non-valvular AF not responding to medical treatment, Isolation of the pulmonary veins antra was performed using three dimensional electroanatomical mapping, detailed voltage map was done in the right and left atrium, before ablation and Low-voltage zones were identified. Follow up of the patients was done for 6 months after the procedure to detect recurrence of AF. RESULTS: Left atrium fibrosis was present in 6 (21.4%) cases, right atrium fibrosis was present only in 1 (3.6%) case and recurrence of atrial fibrillation after 6 months occurred in 12 (42.9%) cases. AF burden was significantly higher in the recurrence group [50.33 ±19.7 (48) (hour/month)] as compared to no recurrence group [29.5 ± 6.99 (32) (hour/month)] with P-value 0.002 and the incidence of left atrium fibrosis was significantly higher in the recurrence group as compared to no recurrence group with P-value 0.024. The only significant predictors of recurrence were the presence of left atrium fibrosis (OR 10.71, 95% CI 1.05 to 109.78; P=0.046) and AF burden (OR 1.14, 95% CI 1.02 to 1.27; P=0.023). The only significant predictor of the presence of left atrium fibrosis was AF burden (OR 1.06, 95% CI 1.01 to 1.13; P=0.031). CONCLUSIONS: The presence of the atrial fibrosis in the left atrium is an independent predictor of atrial fibrillation recurrence after pulmonary vein antrum isolation after 6 months without left atium substrate modification.