The association of vasoactive agents with postoperative atrial fibrillation after cardiac surgery

Abstract Background Postoperative atrial fibrillation (POAF) constitutes a common complication after cardiac surgery, that is associated with major adverse cardiac events and prolonged hospital stay. Causes for developing POAF are multifactorial. While there are non-modifiable predisposing characteristics such as higher age or comorbidities, several factors of postoperative patient management could be modulated in order to lower the individual risk of POAF. In this regard, inotropic agents (i.e. norepinephrine, dobutamine) in postoperative care are known to possess arrhythmogenic potential. It is unknown, however, to what extent this postoperative catecholamine therapy influences the emergence of POAF. Methods Within this prospective observational study 514 patients were included who underwent elective coronary artery bypass graft (CABG), heart valve, or combined valve/CABG surgery. In total, 438 patients received vasoactive drugs during the postoperative course. These participants were subsequently followed for the occurrence of POAF. Results Overall, 43.4% (n=190) of all catecholamine-receiving patients developed POAF. Interestingly, participants who developed POAF had received significantly higher median doses of norepinephrine as compared to non-POAF individuals (POAF: 0.083μg/kg/min vs. non-POAF: 0.062μg/kg/min; p=0.001), while the median dobutamine dose did not significantly differ between groups (POAF: 3.332 μg/kg/min vs. non-POAF 3.289μg/kg/min; p=0.254). Moreover, regression analysis identified norepinephrine with an adjusted hazard ratio (HR) per standard deviation (1-SD) of 1.388 (95% CI:1.114-1.728; p=0.003) as an independent risk factor for the occurrence of POAF. In addition, a norepinephrine dose of 0.18μg/kg/min was determined as the cut-off value, from which the POAF risk increased significantly. Notably, no association between dobutamine and POAF was found (adjusted HR 1.140 [95% CI:0.773-1.683; p=0.508]). Conclusion Within this prospective observational study, we were able to demonstrate that the postoperative use of norepinephrine, in contrast to dobutamine, represents an independent risk factor for the development of POAF. Furthermore, a dose dependency was found for norepinephrine from which the risk for POAF substantially increased. To prevent POAF episodes and thus prolonged intensive care unit stay it may be suggested to further promote rapid norepinephrine weaning if feasible.