Influence of body mass index on recurrence of atrial fibrillation after electrical cardioversion

Background Several studies have shown an independent relationship between body mass index (BMI) and the incidence of atrial fibrillation (AF). However, little is known about the influence of BMI on AF recurrence after electrical cardioversion (ECV). Methods We selected 1121 patients who reverted to sinus rhythm after scheduled ECV and were included in three prospective Spanish registries of ECV in persistent AF. The patients were classified according to baseline BMI into three categories (normal weight, overweight, obesity). We assessed the influence of BMI on the rate of AF recurrence at 3 months. Results We identified 538 patients (48%) who had AF recurrence in the first 3 months after successful ECV. The patients who suffered AF recurrence had a higher BMI than those who remained in sinus rhythm (29.66 +/- 4.57 vs. 28.87 +/- 4.64 Kg/m(2), respectively; p = 0.004). We observed a higher incidence of AF recurrence in the overweight and obese patients (BMI >= 25 kg/m(2)) than in those classified as normal weight (50.5% vs. 35.6%, respectively; p<0,001). BMI >= 25 Kg/m(2) was shown to be independently related to of AF recurrence in the multivariate analysis (OR = 1.75, 95% confidence interval = 1.20-2.58; p = 0.004). Conclusions Increased BMI is independently related to AF recurrence after ECV. BMI should also be taken into account when making decisions about the indication for ECV in persistent AF.