The Impact of Obesity on the Left Atrium and Arrhythmia Recurrence in Patients with Atrial Fibrillation Undergoing...

Objectives: Obesity and atrial fibrillation (AF) are strongly linked and are both associated with significant left atrial (LA) pathology. This study aimed to assess differences in LA size and function between obese and non-obese AF patients and to evaluate AF recurrence in both groups. Materials and Methods: We retrospectively analyzed patients undergoing first-time ablation for AF. Obesity was defined as body mass index ≥30 kg/m², and patients were divided accordingly into obese and non-obese groups. Results: Among 672 patients (median age of 66 years; 39.1% women), 308 (45.8%) were obese. Obese patients had significantly larger LA dimensions (LA area, LA volume, and LAVI indexed to height² (but not that indexed to body surface area (BSA)); p < 0.001), as well as higher LA-pressure-related parameters (LA stiffness index (p = 0.004), E-wave velocity (p = 0.002), and E/e' ratio (p < 0.001)) and invasively measured mean LA pressure (p < 0.0001). However, there were no significant differences in parameters directly reflecting LA function, such as LA emptying fraction, LA reservoir strain, or LA appendage velocity. These findings remained consistent in the sinus rhythm subgroup (n = 374). The 1-year AF recurrence rate did not differ between obese and non-obese groups (data available for 73.8% (496) patients; p = 0.40), regardless of baseline rhythm. Conclusions: In AF patients undergoing their first ablation, obesity was associated with a larger LA size and higher LA pressure. In obese individuals, indexing LA dimensions to height² seems to better reflect LA enlargement than indexing to BSA. LA function and AF recurrence rates after a 1-year follow-up period were similar between obese and non-obese patients.