Characterization of Post Coronary Artery Bypass Grafting Atrial Fibrillation Patterns: Rationale and Design of an Investigator-Initiated Observational Study

New-onset postoperative atrial fibrillation (POAF) after cardiac surgery is associated with increased rates of adverse events (including mortality and stroke). Its incidence after coronary artery bypass grafting (CABG) is considered to be approximately 30%, and it is believed to be a transient condition. However, studies investigating POAF after CABG fail to provide appropriate data on incidence and arrhythmia patterns due to the use of intermittent rhythm detection strategies. These methods have a low sensitivity as compared with continuous monitoring. Subsequently, studies using these techniques most likely do not identify all patients with arrhythmia and do not adequately demonstrate the long-term incidence of arrhythmia, which in turn may affect its association with adverse events. The Characterization of Post Coronary Artery Bypass Grafting Atrial Fibrillation Patterns (CABG-AF) study (German Clinical Trials Register Number: DRKS00018887) tests the hypothesis that the incidence of AF in the first 12 months after CABG is significantly underestimated. CABG-AF is an investigator-initiated multicenter, prospective, observational study in which 196 patients with no history of arrhythmia who underwent first-time CABG receive an insertable cardiac monitor for continuous postoperative rhythm monitoring. The primary end point of the study is any episode of AF within the first 12 months after surgery. Secondary end points include AF burden, AF density, and the ratio of silent to symptomatic AF episodes. End points will be investigated by automatic and patient-initiated data transfers from the implanted device, by telephone interview of patients, and by follow-up forms sent to patients by mail. The patients will be followed for a planned follow-up of 3 years. In conclusion, the CABG-AF study will provide information on the true incidence of AF after CABG and on the temporal patterns of the arrhythmia.