Left Atrial Dysfunction Is a Predictor of Postcoronary Artery Bypass Atrial Fibrillation: Association of Left Atrial Strain and Strain Rate Assessed by Speckle Tracking

Abstract

Background: Even though atrial fibrillation (AF) is the most common arrhythmia after coronary artery bypass grafting (CABG), its etiology remains poorly understood. Several factors are linked to postoperative AF (POAF), including advanced age and systemic inflammation. However, left atrial (LA) contractile dysfunction has not been evaluated in the perioperative scenario. Aim: To evaluate LA function through strain and strain rate in patients with coronary artery disease undergoing CABG and its correlation with POAF. Methods: We studied 70 patients undergoing CABG in sinus rhythm at the time of surgery. Preoperative echocardiography with evaluation of LA strain and strain rate by speckle tracking was performed. The occurrence of POAF was evaluated by continuous monitoring. Baseline and postoperative C-reactive protein (CRP) levels were measured to evaluate systemic inflammation. Results: After 1-week follow-up 26% of subjects developed AF. LA strain s wave (LASs) and LA strain rate s (LASRs) and a wave (LASRa) were significantly decreased in patients who developed POAF: LASs (10 +/- 1% vs. 24 +/- 1%, P < 0.001), LASRs (0.6 +/- 0.1 sec1 vs. 1.2 +/- 0.1 sec-1, P < 0.001), LASRa (-0.6 +/- 0.1 sec1 vs. 1.8 +/- 0.1 sec-1, P < 0.001). LASRs, LASRa, age, and LA volume were independent predictors of POAF. CRP at baseline was similar irrespective of POAF development. Conclusions: LA dysfunction, evaluated by strain and strain rate is an independent predictor of POAF and contributes to classic risk factors like age and atrial volume. (Echocardiography 2011;28:1104-1108)