Incidence and predictors of new-onset silent atrial fibrillation after coronary artery bypass graft surgery

Abstract

Aims. We investigated the incidence, risk factors, and prognostic impact of silent atrial fibrillation (AF) after coronary artery bypass graft (CABG) surgery. Methods. This observational study prospectively included 100 patients referred for CABG surgery. Holter ECG monitoring was used to record every arrhythmic event for 7 days. AF was defined as at least one episode >30 s. Episodes recorded on Holter ECG monitoring but not clinically identified were classified as silent AF. Results. Among 34 patients who developed new-onset AF, 13 had silent AF. Compared with patients with maintained sinus rhythm (SR), silent AF patients had a significantly higher logistic EuroSCORE (2.9 (1.5-5.2) versus 2.3 (1.4-3.7), p=0.017) and were more likely to have previous sleep apnea (31% versus 8%, p=0.016) and left atrial diameter >45 mm (36% versus 5%, p=0.002). At one-year follow-up, 30% of silent AF patients had developed symptomatic AF versus 7% in the SR group (p=0.03) and 11% in the clinical AF group (p=0.21). Conclusion. After CABG surgery, silent AF is common and may be associated with a higher incidence of recurrences at one-year follow-up than clinical AF. Improved screening for silent AF may help to reduce thromboembolic events in this high-risk population.