Association of left atrial strain by cardiovascular magnetic resonance with recurrence of atrial fibrillation following catheter ablation

Background Atrial fibrillation (AF) is a progressive condition, which is characterized by inflammation/fibrosis of left atrial (LA) wall, an increase in the LA size/volumes, and decrease in LA function. We sought to investigate the relationship of anatomical and functional parameters obtained by cardiovascular magnetic resonance (CMR), with AF recurrence in paroxysmal AF (pAF) patients after catheter ablation. Methods We studied 80 consecutive pAF patients referred for ablation, between January 2014 and December 2019, who underwent pre- and post-ablation CMR while in sinus rhythm. LA volumes were measured using the area-length method and included maximum, minimum, and pre-atrial-contraction volumes. CMR-derived LA reservoir strain (R), conduit strain (CD), and contractile strain (CT) were measured by computer assisted manual planimetry. We used a multivariate logistical regression to estimate the independent predictors of AF recurrence after ablation. Results Mean age was 58.6 +/- 9.4 years, 75% men, mean CHA(2)DS(2)-VASc score was 1.7, 36% had prior cardioversion and 51% were taking antiarrhythmic drugs. Patients were followed for a median of 4 years (Q1-Q3 = 2.5-6.2 years). Of the 80 patients, 21 (26.3%) patients had AF recurrence after ablation. There were no significant differences between AF recurrence vs. no recurrence groups in age, gender, CHA(2)DS(2)-VASc score, or baseline comorbidities. At baseline, patients with AF recurrence compared to without recurrence had lower LV end systolic volume index (32 +/- 7 vs 37 +/- 11 mL/m2; p = 0.045) and lower x2107;CT (7.1 +/- 4.6 vs 9.1 +/- 3.7; p = 0.05). Post-ablation, patients with AF recurrence had higher LA minimum volume (68 +/- 32 vs 55 +/- 23; p = 0.05), right atrial volume index (62 +/- 20 vs 52 +/- 19 mL/m2; p = 0.04) and lower LA active ejection fraction (24 +/- 8 vs 29 +/- 11; p = 0.05), LA total ejection fraction (39 +/- 14 vs 46 +/- 12; p = 0.02), LA expansion index (73.6 +/- 37.5 vs 94.7 +/- 37.1; p = 0.03) and x2107;CT (6.2 +/- 2.9 vs 7.3 +/- 1.7; p = 0.04). Adjusting for clinical variables in the multivariate logistic regression model, post-ablation minimum LA volume (OR 1.09; CI 1.02-1.16), LA expansion index (OR 0.98; CI 0.96-0.99), and baseline x2107;R (OR 0.92; CI 0.85-0.99) were independently associated with AF recurrence. Conclusion Significant changes in LA volumes and strain parameters occur after AF ablation. CMR derived baseline x2107;R, post-ablation minimum LAV, and expansion index are independently associated with AF recurrence.