Subacute postoperative atrial fibrillation after heart surgery: incidence and predictive factors in cardiac rehabilitation

Abstract

\n \n \n Type of funding sources: None.\n Background. Postoperative atrial fibrillation (POAF) is the most common arrhythmic complication following cardiac surgery. It may occur between the second and fourth postoperative days as acute POAF, or within 30 days as subacute POAF (sPOAF). The incidence varies from 15% to 60%, with the highest rates observed in patients undergoing valvular surgery. POAF is associated with longer hospital stay and higher thromboembolic risk, which consistently increase patients’ morbidity and mortality. Identification of high-risk categories may allow optimization of in-hospital prevention and treatment, possibly improving clinical outcomes.\n Aim of the study. The aim of this study was to assess the incidence of sPOAF and to identify possible predictors in patients performing Cardiovascular Rehabilitation (CR) after Cardiac Surgery (CS).\n Methods. A single-centre retrospective study was performed on 383 post-cardiac surgery patients hospitalised in our CR Unit for inpatient rehabilitation. The entire population was on sinus rhythm at the admission in CR and continuous monitoring with 12-lead ECG telemetry was performed during the hospital stay. We calculated the incidence of sPOAF and then evaluated the predictive value of the following variables: anamnestic data, type of cardiac intervention, clinical course in both CS and CR Unit, laboratory parameters including baseline neutrophil-to-lymphocyte ratio (NLR).\n Results. Median age was 65 years (63% male). sPOAF was documented in 122 cases (31.9%). Patients developing sPOAF were older [median age 69 (63-76) vs. 61 (51-70); p\u2009<\u20090.001)], more frequently underwent complex surgical procedures (50% vs. 36%; p\u2009=\u20090.009) and were known for previous episodes of atrial fibrillation (27.9% vs. 11.2%; p\u2009<\u20090.001). On the first day after surgery (T1), sPOAF group showed higher values of glycemia [median 155 (126.5–186.8) vs. 129 (106.5–164); p\u2009<\u20090.001] and troponin T [median 721.5 (470.1–1084.3) vs. 488 (301.6-776.2); p\u2009<\u20090.001]. The multivariate analysis identified advanced age (OR 1.04, 95% CI 1.01-1.08; p\u2009=\u20090.023), acute POAF in the Cardiac Surgery Unit (OR 3.51, 95% CI 1.62-7.59; p\u2009=\u20090.001), baseline NLR (OR 1.46, 95% CI 1.10-1.93; p\u2009=\u20090.008) and T1-troponin > 552 ng/L (OR 4.16 95% CI 1.50-11.53; p\u2009=\u20090.006) as independent risk predictors of sPOAF during the CR period.\n Conclusions. sPOAF is common after cardiac surgery occurring in 31.9% of patients during CR. Age, acute POAF, baseline NLR and elevated troponin T on the first postoperative day were shown predictors of increased sPOAF risk. Recognition of new predictors of POAF could be helpful to better stratify patients, improving management strategies and outcomes.\n