Atrial fibrillation after minimally invasive coronary artery bypass grafting: A retrospective, matched study

Background: Atrial fibrillation after cardiac operations is a source of mor bidity and resource consumption, Various factors common to cardiac operatio ns have been cited as causal. Comparison of the incidences of atrial fibril lation after conventional cardiac operations and minimally invasive cardiac operations may provide some insight into the mechanisms of this complicati on, Methods: All patients undergoing minimally invasive direct coronary art ery bypass grafting from January 26, 1996, through September 17, 1997, were evaluated for the occurrence of in-hospital postoperative atrial fibrillat ion, Data from these 55 patients were compared with data from a control coh ort of patients undergoing conventional, solitary coronary artery bypass gr afting. Each patient undergoing minimally invasive direct coronary artery b ypass grafting was matched by age (+/- 3 years) and date of operation (+/- 7 days) with a patient undergoing conventional coronary artery bypass graft ing. Results: During the period since the advent of minimally invasive dire ct coronary artery bypass grafting at our institution, the incidence of pos toperative atrial fibrillation has been slightly lower among the patients u ndergoing this form of coronary artery bypass grafting (26%) than among the total population of patients undergoing conventional coronary artery bypas s grafting (34%). Comparison of the age-matched groups, however showed the incidence to be slightly but not significantly greater in the minimally inv asive direct coronary artery bypass grafting cohort (13/55, 24%) than in th e conventional coronary artery bypass grafting cohort (11/55, 20%; P =.6). The minimally invasive direct coronary artery bypass grafting group was les s likely to be discharged with antiarrhythmic therapy than was the conventi onal coronary artery bypass grafting group (6 versus 10; P =.006), Conclusi ons: According to these data, mechanisms traditionally implicated in atrial fibrillation after coronary artery bypass grafting, such as the use of car diopulmonary bypass, mechanical manipulation of the atrium, and atrial isch emia, are not causal but may be related to the duration of the arrhythmic c omplication, Strategies directed toward management and reduction of the inc idence of postoperative atrial fibrillation should be focused accordingly.