Outcomes of patients undergoing atrial fibrillation ablation in relation to BMI

 Background:

Obesity represents a relevant risk factor for the manifestation of atrial fibrillation (AF) and will show a global increase in prevalence. AF ablation is the gold standard for rhythm control therapy. In addition to traditional thermal ablation approaches, such as RF- and cryoballoon-ablation, a new non-thermal approach using pulsed field ablation (PFA) has been introduced. AF ablation in overweight and obese patients is increasing, however data on this patient cohort in relation to the ablation mode is sparse.

Aim:

To investigate the safety and efficacy of different ablation modes in relation to the body weight.

Methods:
Patients with symptomatic AF undergoing their first PVI in our tertiary-center were retrospectively analyzed. All patients gave written informed consent. Baseline clinical parameters, procedural parameters and follow-up data were collected. Diagnosis of obesity was made according to the body mass-index:  normal weight (BMI 18,5-25 kg/m²), pre-obese (BMI 25-30 kg/m²), obese class I (BMI 30-35 kg/m²), obese class II (BMI 35-40 kg/m²) and obese class III (BMI over 40 kg/m²). Recurrence of atrial tachyarrhythmia was diagnosed via ECG or implanted device. Atrial fibrillation recurrence in relation BMI was analyzed.  

Results:
Four-hundred fifteen patients (61% male, 66 ± 11 years, mean BMI 28.2 ± 5 kg/m², 60% paroxysmal AF) were included. Patients were categorized into normal weight (BMI 18,5-25 kg/m²: 28%), pre-obese (BMI 25-30 kg/m²: 42%), obese class I (BMI 30-35 kg/m²: 21%), obese class II (BMI 35-40 kg/m²: 7%) and obese class III (BMI over 40 kg/m²: 3%). AF ablation using RF was performed in 45%, cryoballoon ablation in 13% and PFA in 42%. In relation to BMI, the used ablation mode was as follows: normal weight (RF: 25%, cryoballoon: 36%, PFA: 28%), pre-obese (RF: 41%, cryoballoon: 38%, PFA: 42%), obese class I (RF: 24%, cryoballoon: 15%, PFA: 19%), obese class II (RF: 9%, cryoballoon: 9%, PFA: 5%) and obese class III (RF: 1%, cryoballoon: 2%, PFA: 6%). Mean short time follow-up was 96 ± 55 days and 295 patients could be analyzed in a first follow-up. Overall AF recurrence rate was 31% (90 of 295 patients) and distribution according to BMI were: normal weight 31% (RF: 36%, cryoballoon: 30%, PFA: 27%), pre-obese 22% (RF: 19%, cryoballoon: 33%, PFA: 24%), obese class I 48% (RF: 56%, cryoballoon: 40%, PFA: 38%), obese class II 24% (RF: 27%, cryoballoon: 33%, PFA: 14%) and obese class III 33% (RF: 0% (no patient in this obesity class underwent ablation with RF energy, cryoballoon: 0% (1 patient in this obesity class underwent ablation and had no recurrence), PFA: 38% (8 patients underwent ablation using PFA and 3 had a recurrence)).

Conclusions:
In this retrospective single-center observation of AF patients, the chosen ablation mode was similar in relation to the different BMIs, with a tendency towards higher use of single-shot devices in higher obesity classes. AF recurrence rates were similar in non-obese, pre-obese and obese patients, but more patients are needed to improve validity.