BACKGROUND: It has been shown that obesity and higher body mass index (BMI) are associated with higher recurrence rate of atrial fibrillation (AF) after successful catheter ablation (CA). The same has been proven for left atrial volume index (LAVI). It has also been shown that there is a correlation between LAVI and BMI. However, whether LAVI prognostic impact on AF recurrence is BMI independent, remains unclear. METHODS: We prospectively included 62 patients with paroxysmal AF who were referred to our institution for CA. All patients underwent radiofrequency CA with standard pulmonary veins isolation. Transthoracic 2-D echocardiography was performed one day after CA to obtain standard measures of cardiac function and morphology. Recurrence was defined as documented AF within 6 months of follow-up period. Patients were also instructed to visit outpatient clinic earlier in case of symptoms suggesting AF recurrence. RESULTS: We observed AF recurrence in 27% of patients after 6 months. The mean BMI in our cohort was 29.65 ± 5.08 kg/cm2 and the mean LAVI was 38.04 ±11.38 ml/m2. We further divided patients into 2 groups according to BMI. Even though LAVI was similar in both groups, we found it to be significant predictor of AF recurrence only in obese patients (BMI ≥ 30), but not in the non-obese group (BMI < 30). There was also no significant difference in AF recurrence between both cohorts. The significance of LAVI as AF recurrence predictor in obesity group was also confirmed in multivariate model. CONCLUSION: According to our results LAVI tends to be significant predictor of AF recurrence after successful catheter ablation in obese patients, but not in normal-weight and overweight patients. This would suggest different mechanisms of AF in non-obese patients in comparison to the obese. Further studies are needed in this regard.