Left-atrial function in relation to BMI in patients undergoing catheter ablation for atrial fibrillation

Background Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia. Catheter ablation (CA) has become first line therapy for patients with symptomatic AF. Overweight/ obesity are both a common comorbidity and risk factor for AF, as they promote atrial remodeling. Atrial remodeling can lead to left-atrial (LA) – dysfunction. LA reservoir strain (LArS) is suggested to be a sensitive marker for LA-function. However, data on body mass index (BMI) – related differences in LA-function in the context of CA are limited. Purpose To evaluate the relationship of BMI and LA-function and analyze in relation to the outcome after CA for AF. Methods Patients with symptomatic AF undergoing first CA for AF between 2018 and 2024 were included. Inclusion criteria were as following: No prior CA in the LA, pre- and postprocedural transthoracic echocardiography (TTE) in continuous sinus rhythm (SR) of adequate image quality and follow-up information about postprocedural outcome after blanking period. LA strain analysis was performed for pre- and postprocedural TTE. Clinical as well as procedural parameters were retrospectively analyzed. BMI & postprocedural outcome after CA were correlated with biomarkers and parameters of LA-function. Correlation between BMI and markers of LA-function was assessed using spearman`s rho. Results The study population comprised 220 patients, with 30% of patients having normal weight (NW) (BMI< 25kg/m², n=66), 42% being overweight (OW) (BMI 25-29.9kg/m², n=93), and 28% of patients being obese (OB) (BMI≥30kg/m², n=61). Higher BMI was neither associated with alterations of preprocedural LArS (ρ=-0.015, P=0.82), nor LAVI (ρ=0.097, P=0.15), nor NT-proBNP (ρ=-0.058, P=0.406). Within 12 months follow-up recurrence rate was 32%. There were no differences across BMI categories (NW: 32%, OW: 30%, OB: 34%; log rank: chi²=0.703, P=0.704). In contrast, patients with recurrence of AF (n=70) showed significantly impaired markers of LA-function in comparison to patients without recurrence: Reduced preprocedural LArS (Recurrence: 20.09 ± 6.37% vs. No recurrence: 24.19 ± 6.77 %, P<0.001), higher values for preprocedural LAVI (Recurrence: 41.90 [27.95 – 51.10] ml/m² vs. No recurrence: 35.05 [26.60 – 44.75] ml/m², P<0.046) and preprocedural NT-proBNP (Recurrence: 853.00 [294.00 – 2011.00] pg/dl vs. No recurrence: 386.00 [170.00 – 874.00] pg/dl, P<0.001). Multivariate regression analysis – including sex, age, comorbidities, BMI and markers of LA-function – revealed only preprocedural LArS to be an independent predictor of AF recurrence after CA (OR 0.891, 95% CI: 0.838-0.947; P<0.001). Conclusion In our cohort, no significant correlations were observed between BMI and markers of LA-function. Outcome after CA was not influenced by BMI category of the patient. Yet, patients with impaired markers of LA-function showed higher recurrence rates after CA. Lager studies are needed to confirm these findings.