Increased intracardiac vascular endothelial growth factor levels in patients with paroxysmal, but not persistent atrial fibrillation

Abstract

Although inflammation appears to play a pivotal role in the pathophysiology of atrial fibrillation (AF), the source of inflammation is unknown. We hypothesized that multilevel measurement of several inflammatory proteins in AF patients would help assess the extent and the source of inflammation. Thirty-nine patients with paroxysmal AF, 33 with persistent AF, and 9 control patients with Wolff-Parkinson-White syndrome were enrolled. Peripheral, left atrial, coronary sinus, and pulmonary vein blood samples were obtained during catheterization. Serum levels of vascular endothelial growth factor (VEGF), interleukin-8 (IL-8), soluble intercellular adhesion molecule 1 (sICAM-1), and transforming growth factor-β1 (TGF-β1) were measured at the four sampled sites. Interleukin-8, sICAM-1, and TGF-β1 levels did not differ among groups at any of the sampled sites. Peripheral VEGF levels were higher in both paroxysmal and persistent AF patients than in controls (P ≤ 0.03). Left atrial VEGF levels were higher in paroxysmal AF (P = 0.05), but not in persistent AF (P = 0.32), compared with controls. Coronary sinus and pulmonary vein VEGF levels did not differ significantly among groups. Low levels of several inflammatory markers in both paroxysmal and persistent AF patients suggest that the inflammatory process is of low grade, if present. In the context of normal pulmonary vein VEGF levels, the heart itself is the most likely source of high left atrial VEGF levels in paroxysmal AF patients; however, this disorder appears to be a transient event in the natural history of AF.