Factors influencing post-coronary artery bypass grafting atrial fibrillation episodes.

Copyright © Polskie Towarzystwo Kardiologiczne INTRODUCTION Although postoperative atrial fibrillation (AF) was first described in 1959 as a complication of mitral valvotomy, this arrhythmia still remains the most common complication following cardiac surgery [1–8]. Postoperative AF has significant adverse effects on patient recovery, affecting shortand long-term outcomes [4–19]. In addition, the impact of postoperative AF on hospital resources is substantial [14–23]. Therefore, intensive research has been carried out to address the issue of postoperative AF, its prevention and preoperative risk assessment. A common approach in previous studies was to look for preoperative means of stratification to enable novel preventive therapeutic strategies [4–10, 24]. Although several studies have analysed the risk factors for postoperative AF, the exact pathophysiology of this complication has not yet been elucidated [2]. Postoperative AF is the consequence of the interplay of different mechanisms, with patient-related factors and cardiopulmonary bypass (CPB) being major causes [2–4, 10]. A re-entry mechanism is considered as the main contributor to the onset of AF after cardiac surgery, resulting from an inhomogeneous distribution of atrial refractoriness [24–28]. Alterations of automaticity are considered to be other causative factors [29–31]. The phenomenon of altered automaticity requires an atrial substrate, which may reflect an association with multiple preoperative predisposing factors [25–31]. Operative and postoperative factors may also contribute to the development of this structural substrate [3–10, 24]. Therefore, several risk factors acting at pre-, intra-, and postoperative levels have been recognised [2, 3]. SEARCH STRATEGY We searched using electronic databases [PUBMED/MEDLINE (1966–April 2013), EMBASE and SCOPUS (1965–April 2013), DARE (1966–April 2013)]. Additionally, abstracts from national and international cardiovascular meetings were searched. Where necessary, the relevant authors were contacted to obtain further data. Retrospective studies, as well as small studies with the number of patients below 100, were excluded from the review. The main data search terms were: ‘postoperative atrial fibrillation’, ‘postoperative AF’, ‘POAF’, ‘arrhythmias’, ‘risk factors’, ‘predictors’, and ‘clinical trials’.