New Onset Postoperative Atrial Fibrillation: Relevance of Peri- and Intraoperative Characteristics for Incidence of Atrial Fibrillation and Patient Outcome?

Objectives: New onset atrial fibrillation (NOAF) is distinct from paroxysmal or persistent atrial fibrillation (AF) and is assumed to increase the perioperative risk in standard cardiac surgery compared with minimally invasive procedures. We analyzed characteristics of patients and procedures to identify disposition, impact for perioperative morbidity and therapeutic targets for prevention of NOAF.

Methods: A total of 200 patients (sinus rhythm (SR)), undergoing coronary artery bypass surgery, aortic valve surgery or a combination of both were studied prospectively. Cardiovascular morbidity, serum parameters and perioperative therapy were recorded. NOAF incidence and morbidity, stroke and mortality were recorded. Serum samples were taken before, during or after operation, at incidence (NOAF) or discharge (SR). Right atrial appendage samples were screened for expressional patterns.

Results: Twenty-six patients of patients developed NOAF at postoperative day 2.5 ± 0.27. All patients regained SR by medical (91.2%) or electrical (8.8%) cardioversion. NOAF incidence did not differ regarding sex (p = 0.377), type of operative procedure (p = 0.106), extracorporal circulation time (p = 0.673), clamp time (p = 0.925), BMI (p = 0.499), diabetes mellitus (p = 0.130), left ventricular function (p = 0.225), postoperative delirium (p = 0.064) and wound healing disorders (p = 0.726), all reported to predispose for structural remodeling in AF before. NOAF increased duration of intensive care treatment (156.93 ± 35.83 versus 76.58 ± 13.15 hours, p = 0.023), need of hemodynamic treatment (p = 0.001) but did not prolong mechanical ventilation (p = 0.531). We observed 2 deaths in SR patients (sepsis). 1 NOAF and 3 SR patients developed postoperative stroke (p = 0.897). Age (70,608 ± 1,326 vs. 65,397 ± 1,038 years; p = 0.026), reoperation (p = 0.001), preoperative STEMI/NSTEMI (p < 0.001), increased left atrial area (19,903 ± 1,007 vs. 16,995 ± 0.792, cm², p = 0.041), use of diuretics (p = 0.01), reduced glomerular filtration rate (76,474 ± 3,986 versus 92,740 ± 4,200; p = 0.028), increased white blood cell count (16,940 ± 1,111 versus 14,538 ± 0.488; p = 0.023), and transfusion of red blood cells (1,114 ± 0,309 vs. 0.527 ± 0.107; p = 0.024) increased NOAF incidence.

Conclusion: Postoperative NOAF is frequent and may complicate postoperative course. Here, predisposing risk factors may offer therapeutic targets to reduce NOAF and perioperative morbidity. However, maintenance of NOAF is rare. Therefore, initiating mechanisms may be distinct from paroxysmal and persistent AF.

No conflict of interest has been declared by the author(s).