Left atrial function in obese and non-obese patients undergoing percutaneous pulmonary vein isolation

Obesity constitutes a risk factor for atrial fibrillation (AF) and modifies the efficacy of invasive AF treatment. Left atrial (LA) global longitudinal strain (GLS), which is measured using speckle-tracking echocardiography (STE), is one of the new methods that are helpful in evaluating the function of LA. The aim of the study was to evaluate LA function in obese and non-obese patients that were undergoing percutaneous pulmonary vein isolation (PVI) before and 6 months after the procedure. 89 patients (F/M: 31/58; mean age: 55.8 ± 9.8 years) with paroxysmal or persistent symptomatic AF that had been qualified for percutaneous PVI were prospectively enrolled in the study. Body mass index (BMI) constituted as a discriminating factor for the study groups: obese group: BMI ≥ 30 kg/m² (29 patients, F/M: 13/16, mean age: 55.13 ± 10.1 years) and non-obese group BMI < 30 kg/m² (60 patients, F/M: 18/42, mean age: 57.17 ± 9.0 years). Transthoracic echocardiography (TTE) with LA GLS and segmental longitudinal strain were analysed 1 day before and 6 months after PVI. PVI efficacy was evaluated 6 months after PVI via a seven-day Holter monitoring. Baseline analysis revealed significantly lower two-chamber (2-Ch) LA GLS in the obese patients compared to the non-obese subjects (- 10.55 ± 3.7 vs - 13.11 ± 5.1, p = 0.004). Segmental strain analysis showed no significant differences between the groups. The data that was obtained 6 months after PVI showed a significantly lower 4-Ch LA GLS in the obese patients compared to the non-obese subjects (- 11.04 ± 5.0 vs - 13.91 ± 4.2, p = 0.02), which was accompanied by a significantly lower segmental 4-Ch LA function in the obese patients (med-sept: - 11.66 ± 11.2 vs - 15.97 ± 5.3, p = 0.04; api-sept: - 9.04 ± 6.3 vs - 13.62 ± 6.5, p < 0.001; api-lat: - 7.62 ± 4.0 vs - 13.62 ± 6.5, p < 0.001; med-lat: -9.31 + - 7.9 vs - 15.04 + -  6.3, p = 0.003, global: - 11.04 + - 5.0 vs - 13.91 + - 4.2, p = 0.02). PVI efficacy was confirmed in 52 (58.4%) patients and was similar in both groups. Comparison of the baseline and 6-month strain revealed no differences in LA GLS in either group. Differences in LA GLS before and after the procedure (delta LA GLS) were not obesity dependent. Apical-septal and apical-lateral strain in the obese group, which were measured in 4-Ch view, were significantly lower after the procedure compared to the baseline (p < 0.001). Obese patients with paroxysmal AF were characterised by impaired LA GLS, which is persistent and was accompanied by segmental dysfunction after PVI at the 6-month follow-up. PVI efficacy was comparable between the obese and non-obese patients.