Both clinical and experimental studies highlight inflammation as a predisposing factor for AF and its complications. Nevertheless, the source of high inflammatory proteins in patients with AF is still unknown. We hypothesized that multilevel intracardiac and extracardiac (left femoral vein, coronary sinus, left atrium, pulmonary vein) measurements of several inflammatory proteins (VEGF) would help assessing the extent and the source of inflammation in AF patients.