Atrial fibrillation (AF) commonly develops after cardiac valvular surgery. The objective
of this study was to identify risk factors for postoperative AF following valvular
surgery. A cohort of 915 consecutive adult patients undergoing isolated valvular surgery
with preoperative sinus rhythm was analyzed. Univariate and independent multivariate
risk factors for postoperative AF were determined. A second cohort of 305 patients
with the same inclusion criteria was used to validate the multivariate predictors.
Patients studied had a mean age of 56.1 +/- 14.7 years, 57.9% were men, 79.6% had
a normal left ventricular ejection fraction, and their mean left atrial size was 46.2
+/- 9.3 mm. The incidence of postoperative AF was 36.7%. Independent predictors of
postoperative AF included: advanced age (odds ratio [OR] 1.506 per decade, 95% confidence
interval, [CI] 1.35 to 1.68, p = 0.0001); mitral stenosis (OR 2.066, CI 1.21 to 3.52,
p = 0.0077); left atrial enlargement (OR 1.468, CI 1.07 to 2.01, p = 0.0165); use
of systemic hypothermia (OR 0.572, CI 0.422 to 0.776, p = 0.0003); and a history of
cardiac surgery (OR 0.676, CI 0.465 to 0.981, p = 0.0393). Among these variables,
advanced age, mitral stenosis, and left atrial enlargement were confirmed as independent
risk factors in the validation cohort.