Is the extent of left atrial fibrosis associated with body mass index in patients undergoing pulmonary vein isolation for atrial fibrillation?

Left atrial (LA) fibrosis is associated with a higher rate of recurrence of atrial fibrillation (AF) after pulmonary vein isolation (PVI). Body mass index (BMI) is strongly associated with the prevalence of AF, but there is insufficient data about the association between BMI and LA fibrosis. To examine the association between LA fibrosis and BMI in patients with AF undergoing PVI. In 114 patients an electro-anatomical voltage map was created using the Carto 3 3D system before PVI. The total fibrosis area (voltage criteria ≤ 0.5 mV), percentage and number of fibrotic areas were calculated. A general linear model was used to determine the differences in BMI with confounders between groups of patients with differing extents of fibrosis and numbers of focuses. Advanced fibrosis was found in 53 patients (47%), in up to 9 areas with a median of 2 and an IQR of 0-3. The median total fibrotic area was 27.3 cm2 with an IQR of 0.1 - 30.3 cm2. Patients were stratified by percentage of fibrotic area: < 5%, 5-20%, 20-35% and above 35%, and no significant difference in mean BMI was found between the groups (P = 0.57). When stratified by number of fibrotic areas: 0, 1, 2 and ≥ 3 fibrotic areas, no difference in BMI was noted between the groups (P = 0.67). Fibrosis of the LA, as the strongest predictor of AF recurrence after PVI, is not correlated with BMI in patients with atrial fibrillation where PVI is indicated.