The aim of our study was to investigate atrial conduction time in patients with mitral annulus calcification (MAC) using P-wave dispersion (PWD) and electromechanical coupling measured with the surface electrocardiogram and the tissue Doppler echocardiography. Fifty-nine patients with MAC and 43 control subjects underwent resting the surface electrocardiogram and tissue Doppler echocardiography. The difference between the maximum (Pmax) and minimum P-wave durations was calculated and defined as PWD. Interatrial and intraatrial electromechanical delays were measured with tissue Doppler echocardiography. Both Pmax and PWD were higher in patients with MAC compared with controls (111.4 +/- 15.8 vs 97.3 +/- 18.8 milliseconds; P < .0001 and 46.4 +/- 14.6 vs 31.4 +/- 13.1 milliseconds; P < .0001, respectively). Both interatial and intraatrial conduction time were also delayed in patients with MAC compared with controls (29.8 +/- 13.3 vs 17.6 +/- 12.5 milliseconds; P < .0001; 9.4 +/- 5.1 vs 6.8 +/- 4.0 milliseconds; P < .008, respectively). Left atrial (LA) diameter was significantly higher in patients with MAC compared with controls (35.4 +/- 5.0 mm vs 32.3 +/- 4.2 mm; P < .001). The LA diameter correlated significantly with both interatrial conduction times and PWD (r = 0.56; P < .0001 and r = 0.47; P < .0001, respectively). There is a delay in both intraatrial and interatrial electromechanical coupling intervals in patients with MAC. (C) 2010 Elsevier Inc. All rights reserved.