Preoperative Left Atrial Mechanical Dysfunction Predicts Postoperative Atrial Fibrillation After Coronary Artery Bypass Graft Operation - A Velocity Vector Imaging-Based Study -

Background: The aim of the present study was to evaluate pre-existent subclinical mechanical atrial dysfunction in patients with postoperative atrial fibrillation (POAF) by using novel echocardiographic techniques. Methods and Results: Ninety-six patients with sinus rhythm, undergoing coronary artery bypass graft (CABG) operation were prospectively enrolled. Preoperative left atrial (LA) reservoir, conduit and booster functions were evaluated by 3 different methods: conventional echocardiography, tissue Doppler imaging (TDI), and 2-dimensional strain imaging based-velocity vector imaging (VVI). POAF occurred in 25 out of 96 patients (26%). LA volume index (LAVI) was the only conventional parameter associated with POAF. TDI-derived LA velocities were similar in study groups. In VVI analysis, LA systolic strain, strain rate (SRs) and early diastolic strain rate (ESRd) were impaired in patients who developed POAF after CABG (P=0.0001). Age, LAVI, LA peak systolic strain, SRs and ESRd were found to be the independent predictors of POAF. The optimal cut-off point of 44.0% (88.7% sensitivity, 96% specificity) for LA strain, 1.7s(-1) (88% sensitivity, 86.2% specificity) for SRs and 1.95s(-1) (sensitivity 72%, 70.4% specificity) for ESRd predicted POAF in this study. Conclusions: VVI-derived strain imaging could be used as an adjunctive non-invasive method for evaluating subclinical atrial mechanical dysfunction in patients undergoing CABG. This might help us to identify patients with high risk of POAF in clinical practice. (Circ J 2010; 74: 2109-2117)