Abstract 168: Impact of Obesity and Atrial Fibrillation on Arterial Stiffness

Abstract

Introduction Turbulent blood flow which occurs in atrial fibrillation patients due to an irregular heart rate may lead to vascular abnormalities and increased thrombotic risk. Obesity is an important emerging substrate for the development of atrial fibrillation. Obesity is also associated with endothelial dysfunction and increased arterial stiffness. We sought to determine the impact of obesity on arterial stiffness in patients with atrial fibrillation. Methods 34 patients with atrial fibrillation (age 59±12 years,) were evaluated in lean (n=21) and obese (n=13) subgroups, and compared to age-matched lean (n=15) and obese (n=14) control subjects. Arterial stiffness was assessed using radial applanation tonometry (SphygmoCor). Heart rate adjusted aortic augmentation index (AIx: a measure of arterial stiffness) was calculated from the corresponding waveforms utilizing validated transfer functions. Results Obese controls and obese atrial fibrillation patients had significantly higher AIx (arterial stiffness) than lean controls and lean atrial fibrillation patients (p=0.003 and p=0.03, respectively: Figure). There was no difference in AIx scores between obese atrial fibrillation patients and obese control subjects (p=0.3) and between lean atrial fibrillation and lean control subjects (p=0.8). Conclusion We conclude that obesity is associated with arterial stiffness and atrial fibrillation does not add additional burden. These results suggest the interaction between obesity and atrial fibrillation may contribute to the observed increase in thromboembolic risk, in part, through vascular abnormalities other than increased arterial stiffness.