Increased risk of atrial fibrillation among patients undergoing coronary artery bypass graft surgery while receiving nitrates and antiplatelet agents

BACKGROUND: Postoperative atrial fibrillation (POAF) is a frequent complication of coronary artery bypass graft (CABG) surgery. This arrhythmia occurs more frequently among patients who receive perioperative inotropic therapy (PINOT). Administration of nitrates with antiplatelet agents reduces the conversion rate of cyclic guanosine monophosphate to guanosine monophosphate. This process is associated with increased concentrations of free radicals, catecholamines, and blood plasma volume. We hypothesized that patients undergoing CABG surgery who receive PINOT may be more susceptible to POAF when nitrates are administered with antiplatelet agents. METHODS: Clinical records were examined from a prospectively maintained cohort of 4,124 patients undergoing primary isolated CABG surgery to identify POAF-associated factors. RESULTS: POAF risk was increased among patients receiving PINOT, and the greatest effect was observed when nitrates were administered with antiplatelet therapy. Adjustment for comorbidities did not substantively change the study results. CONCLUSIONS: Administration of nitrates with certain antiplatelet agents was associated with an increased POAF risk among patients undergoing CABG surgery. Additional studies are needed to determine whether preventive strategies such as administration of antioxidants will reduce this risk.