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.