Effects of epicardial fat reduction on P-wave duration of morbidly obese patients submitted to bariatric surgery: an observational study

Introduction: Epicardial fat (EF) is biologically active and, through its paracrine effect, interacts with the atrial myocardium and may be involved in the atrial remodeling observed in obese individuals. P-wave duration (PWD) is a non-invasive marker of atrial conduction time and reflects changes related to atrial remodeling. The effects of the reduction of EF induced by bariatric surgery on PWD have not yet been defined. Methods: We prospectively recruited 22 morbidly obese patients with no other comorbidities at the Unidade de Cirurgia Bariátrica (Bariatric Surgery Unit) of Unviversidade de São Paulo’s Hospital das Clínicas. The patients were submitted to clinical and laboratorial evaluations, 12-lead eletrocardiography (ECG), two-dimensional echocardiogram and 24 h Holter. The same evaluation was performed 12 months after bariatric surgery. In order to make a comparison of the continuous variables, we used the paired and Wilcoxon T tests. To evaluate the association between independent variables, a regression model was used for repeated measures. Results: A total of 20 patients completed the protocol (age: 36.35 ± 10.26 years, 18 women). There was a significant reduction of PWD, body mass index (BMI) and EF after bariatric surgery (p<0.05). There was also an average reduction of 11.55 ± 8.49 ms in PWD. In the multiple regression analysis, an association was observed between the reduction of PWD and the reduction of EF and BMI. Conclusions: In morbidly obese patients with no other comorbidities, the reduction of EF after bariatric surgery was associated with an improvement in atrial remodeling indicated by a significant reduction in PWD.