title: Pre-operative left atrial mechanical function predicts risk of atrial fibrillation following cardiac surgery.
abstract: OBJECTIVE
  The purpose of this study was to examine whether left atrial (LA) mechanical function, as measured by LA total emptying fraction (TEF), is a predictor for the development of post-operative atrial fibrillation (POAF) following cardiac surgery.
  
  
  BACKGROUND
  POAF is an important and frequent complication of cardiac surgery. LA enlargement has been reported to be a risk factor for POAF, but the relationship between LA mechanical function and POAF is not well understood. We examined the relationship between pre-operative LA function and POAF in patients without a history of atrial fibrillation.
  
  
  METHODS
  A total of 101 subjects (mean age 64 ± 13 years) underwent pre-operative transthoracic echocardiograms and were followed for occurrence of POAF during the hospitalization for cardiac surgery. The left atrial maximum volume (LAVmax) and left atrial minimum volume (LAVmin) were measured and indexed to body surface area (LAVmaxI and LAVminI, respectively). LA TEF was calculated as: {[(LAVmax - LAVmin)/LAVmax] × 100%}. Univariate and multivariate analyses examined clinical and echocardiographic predictors of POAF.
  
  
  RESULTS
  POAF occurred in 41% of subjects. Mean LA TEF was 49 ± 15%, mean LAVmaxI was 38 ± 15 ml/m(2), and mean LAVminI was 20 ± 13 ml/m(2). Age, LA TEF, and LAVminI were independent predictors of POAF. LA TEF was lower in patients with POAF compared with those without POAF (43 ± 15% vs. 55 ± 13%, p < 0.001), and patients with a LA TEF <50% had a high risk of POAF (odds ratio: 7.94, 95% confidence interval: 3.23 to 19.54, p < 0.001). Compared with LAVmaxI >32 ml/m(2), LA TEF <50% had higher discriminatory power for POAF, which remained significantly higher when adjusted for age (p = 0.04).
  
  
  CONCLUSIONS
  LA TEF is an independent predictor of POAF and is a stronger predictor of POAF than LAVmaxI is. Impaired LA mechanical function may help to identify patients who are most likely to benefit from prophylaxis for POAF.
authors.affiliation: Cardiovascular Imaging and Hemodynamic Laboratory, Tufts Medical Center, Boston, Massachusetts 02111, USA.
authors.forename: Jessica A
authors.initials: JA
authors.lastname: Haffajee
authors.forename: Yoojin
authors.initials: Y
authors.lastname: Lee
authors.forename: Alawi A
authors.initials: AA
authors.lastname: Alsheikh-Ali
authors.forename: Jeffrey T
authors.initials: JT
authors.lastname: Kuvin
authors.forename: Natesa G
authors.initials: NG
authors.lastname: Pandian
authors.forename: Ayan R
authors.initials: AR
authors.lastname: Patel
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000209:etiology* / Q000503:physiopathology; D016279:Atrial Function, Left; D001900:Boston; D006348:Cardiac Surgical Procedures / Q000009:adverse effects*; D016009:Chi-Square Distribution; D015150:Echocardiography, Doppler; D005260:Female; D006325:Heart Atria / Q000000981:diagnostic imaging; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D011237:Predictive Value of Tests; D011300:Preoperative Care; D011446:Prospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D016896:Treatment Outcome