Prediction of paroxysmal atrial fibrillation after aortic valve replacement in patients with aortic stenosis: identification of potential risk factors.

BACKGROUND AND AIM OF THE STUDY: Paroxysmal atrial fibrillation (AF) is a frequent complication after cardiac surgery. The study aim was to identify preoperative predictors of risk for this condition in patients with aortic stenosis after aortic valve replacement.
METHODS: The influence of clinical, echocardiographic and 24 h electrocardiogram (ECG) parameters on episodes of paroxysmal AF after aortic valve replacement (AVR) in 423 patients (156 women, 267 men; mean age 58 +/- 10 years) with aortic stenosis was analyzed. Episodes of postoperative paroxysmal AF were noted in 120 patients (28%).
RESULTS: Univariate analyses identified the following variables as risk factors for arrhythmia: age, NYHA functional class, history of preoperative paroxysmal AF, left ventricular mass index, >300 supraventricular beats on 24h ECG before surgery, presence of supraventricular tachycardia (SVT), SVT of >5 beats or with a rate >120 beats/min. Concomitant coronary artery bypass (CABG) grafting and presence of enlarged left atrium had no impact. By multivariate analysis, four variables were identified as independent predictors: age (odds ratio 1.7; 95% CI 1.2-2.1); history of paroxysmal AF (OR 3.2; CI 1.4-7.3); presence of >300 supraventricular beats/24 h (OR 1.9; CI 1.1-3.4); and presence of SVT (OR 2.1; CI 1.3-3.4). Discriminatory analysis revealed that a model comprising these four parameters enabled risk prediction in 68% of patients.
CONCLUSION: In patients with isolated aortic stenosis, age, past history of paroxysmal AF episodes, >300 supraventricular beats/24 h and presence of SVT during 24 h before AVR were predictors of postoperative paroxysmal AF episodes. Left atrial diameter and simultaneous CABG during AVR did not influence the likelihood of postoperative paroxysmal AF.