The aim of this retrospective study was to determine the incidence of symptomatic AF of patients who had undergone coronary artery bypass grafting (CABG) during long-term follow-up. The study population included 305 post-CABG patients who were regularly followed in the outpatient clinic. Paroxysmal AF (PAF) was defined as an episode of symptomatic AF when symptoms were prolonged enough for the patient to request medical care. Perioperative AF occurred in 88 (28.9%) patients. Postdischarge symptomatic PAF occurred in 25 (8.2%) patients with an annual incidence of 2% during a mean follow-up of 48 +/- 30 months. Eighteen (20.4%) patients also experienced perioperative AF with an annual incidence of 5.1%, while only 7 (3.2%) of 217 patients, without perioperative AF, had postdischarge AF (P < 0.0003). During long-term follow-up, postdischarge AF has a low incidence and prophylactic antiarrhythmic therapy is not recommended. The method of follow-up and retrospective analysis may understate PAF and even miss some symptomatic episodes. Perioperative AF is a predictor of symptomatic late PAF recurrences, particularly in patients with reduced left ventricular function.