Postoperative atrial fibrillation and mortality after coronary artery bypass surgery.
OBJECTIVE
We sought to determine if the occurrence of postoperative atrial fibrillation (AF) affects early or late mortality following coronary artery bypass surgery (CABG).


BACKGROUND
Atrial fibrillation is the most common arrhythmia seen following CABG.


METHODS
The Texas Heart Institute Cardiovascular Research Database was used to identify all patients that developed AF after isolated initial CABG from January 1993 to December 1999 (n = 994). This population was compared with patients who underwent CABG during the same period but did not develop AF (n = 5,481). In-hospital end points were adjusted using logistic regression models to account for baseline differences. Long-term survival was evaluated using a retrospective cohort design, where Cox proportional hazards methods were used to adjust for baseline differences, and with case-matched populations (n = 390, 195 per arm).


RESULTS
Atrial fibrillation was diagnosed in 16% of the population. Postoperative AF was associated with greater in-hospital mortality (odds ratio [OR] 1.7, p = 0.0001), more strokes (OR 2.02, p = 0.001), prolonged hospital stays (14 vs. 10 days, p < 0.0001), and a reduced incidence of myocardial infarction (OR 0.62, p = 0.01). At four to five years, survival was worse in patients who developed postoperative AF (74% vs. 87%, p < 0.0001 in the retrospective cohort; 80% vs. 93%, p = 0.003 in the case-matched population). On multivariate analysis, postoperative AF was an independent predictor of long-term mortality (adjusted OR 1.5, p < 0.001 in the retrospective cohort; OR 3.4, p = 0.0018 in the case-matched population).


CONCLUSIONS
The occurrence of AF following CABG identifies a subset of patients who have a reduced survival probability following CABG. The impact of various strategies, such as antiarrhythmics and warfarin, aimed at reducing AF and its complications deserves further study.
Villareal
Rollo P
RP
Section of Cardiology, Self Regional Healthcare, Greenwood, South Carolina 29646, USA. rollovillareal@yahoo.com
Hariharan
Ramesh
R
Liu
Brant C
BC
Kar
Biswajit
B
Lee
Vei-Vei
VV
Elayda
MacArthur
M
Lopez
J Alberto
JA
Rasekh
Abdi
A
Wilson
James M
JM
Massumi
Ali
A
D000368:Aged; D001281:Atrial Fibrillation / Q000209:etiology* / Q000401:mortality*; D002300:Cardiac Care Facilities / Q000706:statistics & numerical data; D015331:Cohort Studies; D001026:Coronary Artery Bypass / Q000009:adverse effects* / Q000401:mortality*; D019992:Databases as Topic; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D007902:Length of Stay / Q000706:statistics & numerical data; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000453:epidemiology; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D020521:Stroke / Q000453:epidemiology; D016019:Survival Analysis; D013781:Texas / Q000453:epidemiology; D013997:Time Factors