Impairment of left atrial function predicts post-operative atrial fibrillation after coronary artery bypass graft surgery.
OBJECTIVE
Despite the prevalence of atrial fibrillation (AF) occurring after cardiac surgery, its pathophysiology is incompletely understood. Specifically, whether left atrial (LA) structural remodelling occurs, contributing to a decrement in atrial function and AF has not been previously determined. This study sought to determine the relationship between LA function and post-operative AF.


RESULTS
Three hundred patients undergoing elective coronary artery bypass graft surgery were monitored with intraoperative transoesophageal echocardiography to determine LA function and dimensions. Post-operative AF was monitored with continuous telemetry until hospital discharge. The relationship between clinical factors versus LA function and dimension was assessed using multi-variate logistic regression. By univariate analysis, patients who subsequently developed post-operative AF had a larger LA area and LA appendage area, and lower LA ejection fraction measured in the pre-bypass period compared to those without subsequent AF. By multivariable analysis, in addition to clinical data including age (odds ratio [OR] 1.11, 95% confidence interval [CI] 1.05-1.16, P<0.0001), body surface area (OR 13.31, 95% CI 1.87-94.5, P=0.0097) and white race, post-bypass atrial systolic function (atrial filling fraction 0.36, OR 2.51, 95% CI 1.03-6.13, P=0.04) and abnormal relaxation of the left ventricle (E duration 270 ms) (OR 2.89, 95% CI 1.34-6.24, P=0.0067) independently increased the risk of post-operative AF.


CONCLUSIONS
These results demonstrate that some of the structural and functional changes in the atria common to chronic AF in the elderly population are also prevalent in surgical patients who develop post-operative AF, suggesting that post-operative and chronic AF may have similar pathophysiology.
Department of Anesthesia and Perioperative Care, University of California, 521 Parnassus Avenue, San Francisco, CA 94143-0648, USA. jmleung@itsa.ucsf.edu
Jacqueline M
JM
Leung
Wayne H
WH
Bellows
Nelson B
NB
Schiller
D001281:Atrial Fibrillation / Q000209:etiology* / Q000503:physiopathology; D016279:Atrial Function, Left / Q000502:physiology*; D001026:Coronary Artery Bypass; D003327:Coronary Disease / Q000503:physiopathology / Q000601:surgery*; D017548:Echocardiography, Transesophageal; D005260:Female; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D007430:Intraoperative Care / Q000379:methods; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000209:etiology* / Q000503:physiopathology; D012044:Regression Analysis; D016896:Treatment Outcome