Short- and long-term associations of atrial fibrillation catheter ablation with left atrial structure and function: A cardiac magnetic resonance study

Background The effects of atrial fibrillation (AF) catheter ablation on the left atrium (LA) are poorly understood. Objectives To examine short and long-term associations of AF catheter ablation with LA function using cardiac magnetic resonance (CMR). Methods Fifty-one AF patients (mean age 56±8 years) underwent CMR at baseline, 1 day (n=17) and 11±2 months after ablation (n=38). LA phasic volumes, emptying fractions (LAEF), and longitudinal strain were measured using feature-tracking CMR. LA fibrosis was quantified using late gadolinium enhancement (LGE). Results There were no acute changes in volume, however, active, total LAEF, and peak LA strain decreased significantly compared to the baseline. During long-term follow-up, there was a decrease in maximum but not minimum LA volume (from 99±5.2ml to 89±4.7ml, p=0.009) and a decrease in total LAEF (from 43±1.8% to 39±2.0%, p=0.001). In patients with AF recurrence, LA volumes were unchanged. However, total LAEF decreased from 38±3% to 33±3%; p=0.015. Patients without AF recurrence had no changes in LA functional parameters during follow-up. The amount of LA LGE at long term follow-up was higher compared to the baseline, however was significantly less compared to immediately post procedure (37±1.9 % vs. 47±2.8%, p=0.015). A higher increase in LA LGE extent compared to the baseline was associated with a greater decrease in total LAEF (r=-0.59, p Conclusions LA function is impaired acutely following AF catheter ablation. However, long-term changes of LA function are associated positively with successful restoration of sinus rhythm and inversely with increased LA LGE. This article is protected by copyright. All rights reserved.