The pathophysiology of coronary artery disease (CAD) includes low-grade chronic inflammation. At its turn, inflammation is known to promote myocardial structural remodeling and to increase vulnerability to atrial arrhythmias. Meanwhile, the impact of chronic inflammation on the electrophysiological properties of the atria remains unknown. We aimed to evaluate the impact of low-grade chronic inflammation on atrial electrophysiology in patients with stable CAD undergoing elective coronary artery bypass grafting (CABG). Circulating levels of several inflammatory, angiogenesis, and endothelial dysfunction markers were determined 1 day before CABG in 30 consecutive CAD patients. Right atrial appendage samples were collected during the CABG procedure; action potential recordings were performed in six study patients using the microelectrode technique. Interleukin (IL)-1b (r = 1.00, P = 0.01), IL-6 (r = 0.98, P < 0.01), vascular endothelial growth factor (VEGF) (r = 0.98, P < 0.01), and hemoglobin (r = 0.98, P < 0.01) levels significantly positively correlated with the duration of atrial depolarization. Consequently, IL-6, VEGF, and hemoglobin (r = -0.86, P = 0.03 for all) levels significantly negatively correlated with the velocity of atrial depolarization. There was no significant correlation between any of the studied markers levels and any of the other parameters of the action potential (all P > 0.05). The present study is the first to demonstrate that in patients with stable CAD, chronic inflammation and ischemia are associated with pro-arrhythmic atrial electrical remodeling. These changes may contribute to the increased propensity to postoperative atrial arrhythmias seen in some of the patients undergoing CABG.
Keywords: Action potential; coronary artery bypass grafting; inflammation; ischemia; pro-arrhythmic electrical remodeling.