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 ≤ 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.

Keywords: Electromechanical conduction time, Atrial fibrillation, Cardioversion, Tissue Doppler echocardiography