Does a higher body mass index influence additional presence of low voltage areas in the left atrium in patients with persistent atrial fibrillation?

Abstract

Abstract Introduction Pulmonary vein isolation (PVI) is recommended during all atrial fibrillation (AF) catheter ablation procedures. In nearly half of patients with persistent AF, low voltage areas (LVAs), commonly defined as areas in left atrium (LA) with a bipolar electrogram amplitude of < 0.5 mV, could be documented during electrophysiological study (EP). The remaining presence of these areas in LA after a PVI-only catheter ablation procedure is identified as a risk factor for recurrence of AF. Targeting and ablating (substrate modification) these areas reduces recurrency of AF. Pre-procedural identification of patients with additional LVAs is thus very important, until date very challenging and not established. Many markers are evaluated but it remains elusive. Extensive adipose tissue in obese patients leads to LA enlargement and remodeling via different mechanisms, leading to higher incidence of AF. The link between obesity and presence of LVAs in LA other than of pulmonary veins (PV) is to our knowledge not yet evaluated. Aim of the study Is to evaluate role of body mass index (BMI) in the presence of low voltage areas in left atrium besides pulmonary vein by comparing the BMI in patients with persistent AF with and without LVAs in LA, thus eventually identifying BMI as a possible pre-procedural marker of the presence of these areas. Methodology We analyzed data from 91 consecutive patients with persistent AF undergoing first time LA catheter ablation from 09/2021 until 10/2023 inside of the Jen-PACE study. In all patients a high-density 3D endocardial voltage mapping was carried out using EnSite Precision™/ Ensite X™ and the Advisor™ HD-Grid Mapping Catheter. Results The mean BMI was 29.6 ± 4.8, mean LV-EF was 53,4% ± 9.7, 24 patients (27%) were females, average age was 67 years. Depending on the presence of low voltage areas, the patients underwent either PVI only when no such areas were documented (61 patients, 67%) or PVI and substrate modification (30 patients, 33%) with documentation of LVAs. There was no statistical difference in the BMI between the two groups (29.9 ± 4.9 in patients with PVI only vs 29.0 ± 4.8 in patients with PVI + substrate modification; p=0.37). Furthermore, in a subgroup analysis of only adipose patients with a BMI higher than 30 (44 patients; 48%; mean BMI 33.8 ± 3.0), there was no significant difference in BMI between the two groups (34.2 ± 3.3 in PVI only vs 33.2 ± 2.4 in patients with PVI and substrate modification; p=0.2) Discussion and conclusion Even though a high BMI is generally related to a higher incidence of AF, a higher BMI was not observed in patients having additional low-voltage areas in LA compared to patients in whom such areas could not be identified. Electric remodeling caused by obesity could be rather diffuse than localized in specific areas in LA. BMI is not a pre-procedural marker for the presence of additional low voltage areas in LA.