Success of Radiofrequency Catheter Ablation of Atrial Fibrillation: Does Obesity Influence the Outcomes?

Background: Catheter ablation of atrial fibrillation (AF) is an increasingly popular therapeutic option for symptomatic patients who have failed multiple antiarrhythmic drugs (AADs). Patients of higher body mass index often fail direct current cardioversion. The role of body mass index (BMI) on the success of AF ablation is not well understood. Methods: We prospectively studied 511 patients who underwent AF ablation at the Cleveland Clinic Foundation between 2002 and 2005. Patients were divided into four classes based on their BMI: Class I ( 25); Class II (25.1-30); Class III (30.1-35) and Class IV (>35). These groups were compared for baseline demographic and clinical characteristics. Any recurrence of AF after 3 months of ablation was considered as failure. All classes were followed for at least 12 months and rates of failure were compared. Results: Based on their BMI, 25% of patients were assigned to class I, 37% in class II, 21% in class III and 16% in class IV. Patients of higher classification (class III or IV) were more likely to be male (p<0.001), diabetic (p<0.001), smokers (p=0.002), with coronary artery disease (=0.018), left atrial enlargement (p=0.015) and longstanding AF (p=0.007). Severity of obesity as measured by BMI had a direct correlation to early (p=0.05) and late (p=0.01) recurrence of AF. Conclusion: Obesity is significantly associated with long-term AF recurrence after catheter ablation. Higher incidence of smoking & left atrial enlargement may possibly contribute to higher failure rates in this sub-group of patients.