Body mass index and body fat distribution and new-onset atrial fibrillation: Substudy of the European Prospective Investigation into Cancer and Nutrition in Norfolk (EPIC-Norfolk) study.

BACKGROUND AND AIM: Obesity is a recognized risk factor for new-onset atrial fibrillation (AF). The association between body fat distribution, which is measured by body mass index (BMI) and waist-hip ratio (WHR), its changes, and new-onset AF is conflicting. METHODS AND RESULTS: Participants of the European Prospective Investigation into Cancer and Nutrition in Norfolk cohort study were included, with exclusion criteria of prevalent AF, rheumatic heart disease, and cancer. AF was confirmed by the International Classification of Diseases-10 hospital discharge code I48. Adjusted sex-specific Cox proportional hazards models were used to quantify the AF risk per 1 standard deviation increase and for quintiles of adiposity indices. A total of 10,885 men and 12,857 women were followed up for a median of 19 years, yielding 451,098 person-years. New-onset AF was diagnosed in 1408 (12.9%) men and 1102 (8.6%) women. Multivariable analyses showed that BMI predicted new-onset AF in all, while WHR predicted only in men. New-onset AF risk gradually increased across the range of adiposity indices: for men in the highest BMI quintile, HR: 1.59 (CI 1.32-1.91, p for trend<0.001), whereas for women in the highest BMI quintile, HR: 1.52 (CI 1.23-1.88, p for trend<0.001). Further, for men in the highest WHR quintile, HR: 1.31 (CI 1.09-1.57, p for trend: 0.01), whereas for women in the highest WHR quintile, HR: 1.12 (CI 0.90-1.41, p for trend: 0.17). The change in BMI and WHR was similar in participants with or without new-onset AF. CONCLUSIONS: An increased body mass, as measured by BMI, is associated with an increased risk of developing new-onset AF. More abdominal fat distribution, as measured by WHR, is associated with an increased risk of developing new-onset AF in men but not in women.

Does left atrial epicardial conduction time reflect atrial fibrosis and the risk of atrial fibrillation recurrence after thoracoscopic ablation? Post hoc analysis of the AFACT trial.

OBJECTIVES: To determine the association between left atrial epicardial conduction time (LAECT), fibrosis and atrial fibrillation (AF) recurrence after thoracoscopic surgical ablation of persistent AF. SETTING: Single tertiary care centre in the Netherlands. PARTICIPANTS: Patients with persistent AF from the randomised Atrial Fibrillation Ablation and Autonomic Modulation via Thoracoscopic Surgery (AFACT)-trial were included. Patients eligible for thoracoscopic AF ablation were included, full inclusion and exclusion criteria were previously published. All patients underwent thoracoscopic ablation, encompassing pulmonary vein isolation with an additional roof and trigone lesion. In patients with conduction block across the roof and trigone lesion, LAECT was measured. LAECT was defined as the time to local activation at one side of the roofline on pacing from the opposite side. Collagen fibre density was quantified from left atrial appendage histology. OUTCOME MEASURES: Primary outcome: AF recurrence during 2 years of follow-up. RESULTS: 121 patients were included, of whom 35(29%) were women, age was 60.4±7.8 and 51% (62) had at least one AF recurrence during 2 years of follow-up. LAECT was longer in patients with versus without AF recurrence (182±43 ms vs 147±29 ms, p<0.001). LAECT was longer in older patients, in patients with a higher body mass index (BMI) and in patients using class IC antiarrhythmic drugs. LAECT was shorter in patients with higher collagen fibre density. A previously failed catheter ablation, LAECT and BMI were independently associated with AF recurrence. CONCLUSION: LAECT is correlated with collagen fibre density and BMI and is independently associated with AF recurrence in patients with persistent AF. In these patients, LAECT appears to reflect substrate characteristics beyond clinical AF type and left atrial volume. TRIAL REGISTRATION NUMBER: NCT01091389.