Left atrial electromechanical conduction time can predict six-month maintenance of sinus rhythm after electrical cardioversion in persistent atrial fibrillation by Doppler tissue echocardiography

Background: The purpose of this study was to determine whether atrial electromechanical conduction time (EMT) measured by echocardiography can predict 6-month maintenance of sinus rhythm (SR) after electrical cardioversion in patients with atrial fibrillation (AF).

Methods: Fifty-three patients with persistent AF (>1 month) who had successful cardioversion and 30 controls with SR were prospectively enrolled. SR maintenance was assessed during 6-month follow-up. EMT was measured as the time interval from the onset of the P wave on electrocardiography to the peak of the late diastolic wave from the septal and lateral mitral annulus (EMT-S and EMT-L, respectively) and the lateral tricuspid annulus (EMT-T) on tissue Doppler echocardiography.

Results: Compared with controls, left atrial (LA) volume index, P-wave duration, and EMT were significantly larger in patients with AF (all P values<.001). In patients with AF, the duration of AF (P=.71) and P-wave duration (P=.24) were not different between the SR maintenance group (n=23) and the AF recurrence group (n=30), and there was a trend toward increased LA volume index in the AF recurrence group (47.0+/-12.4 vs 45.3+/-12.6 mL/m2, P=.07). EMT-S and EMT-L were significantly larger in the AF recurrence group (131.4+/-20.9 vs 116.3+/-15.5 ms, P=.005, and 152.2+/-15.7 vs 128.9+/-13.8 ms, P<.001, respectively), but not EMT-T. EMT-S and EMT-L were related to LA volume index (r=.36, P=.008, and r=.33, P=.02, respectively). On multivariate logistic regression analysis, only EMT-L was an independent predictor of identifying patients who remained in SR (P<.001), and the sensitivity and specificity for the prediction of 6-month maintenance of restored SR were 82.6% and 83.3% using a cutoff value of EMT-L<or=138.0 ms (odds ratio, 0.862; 95% confidence interval, 0.788-0.942; P=.001).

Conclusion: LA EMT was significantly prolonged in patients with recurring AF, indicating significantly depressed atrial conduction in enlarged LA, and can predict 6-month maintenance of SR after electrical cardioversion.