Cancer Is a Major Determinant of Postoperative Atrial Fibrillation After Cardiac Surgery

<b>Background/Objectives:</b> Postoperative atrial fibrillation (POAF) occurs frequently after cardiac surgery and is associated with increased morbidity and mortality. The pathogenesis of POAF in this setting is complex and not completely understood. Since cancer is a well-known risk factor for AF, the aim of this study was to identify potential predictors, including cancer, of POAF after cardiac surgery. <b>Methods</b>: This prospective study included 400 consecutive patients in sinus rhythm who underwent elective cardiac surgery in Aretaeio Hospital (Nicosia, Cyprus) from January 2020 till January 2023. The primary outcome was the development of POAF during hospitalization, defined as any documented AF episode lasting >30 s. Predictors of the primary outcome were studied using univariable and multivariable logistic regression analysis. <b>Results</b>: Of the 400 patients (68 [61-73] years, 64 [16%] females) studied, 66 (16.5%) developed POAF. Among the variables examined, the only predictors of POAF were cardiopulmonary bypass time (odds ratio [OR] = 1.001, 95% confidence interval = [95% CI, 1.000-1.001], <i>p</i> = -0.031) and cancer (OR = 3.852, 95% CI = [1.535-9.664], <i>p</i> = 0.004). Cancer was present in 13 (4%) and in 10 (15%) of patients without and with POAF, respectively (<i>p</i> < 0.001). <b>Conclusions</b>: Cancer was associated with a dramatic increase in POAF risk early after elective cardiac surgery in this study. Whether patients developing POAF after cardiac surgery should be searched for cancer deserves further investigation.