Objectives Pwave dispersion and electromechanical delay increase in patients with mitral annulus calcification. We hypothesized that the degree of Pwave dispersion and electromechanical delay increase with increasing extent of calcification.Methods and results We enrolled 50 consecutive subjects with mitral annulus calcification documented by trans-thoracic echocardiography, and 50 matched controls. All subjects underwent 12-lead electrocardiography to measure Pwave dispersion (maximum – minimum Pwave duration), and tissue Doppler imaging to measure electromechanical delay. The time interval from the onset of the Pwave on the electrocardiogram to the onset of the late diastolic a wave (PA interval) was obtained from the lateral and septal mitral annulus, and the tricuspid annulus. Inter-atrial and intra-atrial electromechanical delay were calculated as lateral PA - tricuspid PA, and septal PA - tricuspid PA, respectively. Mitral annulus calcification was assigned as mild, moderate and severe when it affected ≤ one-third, between one-third and two-thirds, and > two-thirds of the annulus, respectively. Mean age was 61.8 ± 9.8 years; 50% were males. Patients with mitral annulus calcification had greater Pwave dispersion, inter-atrial and intra-atrial electromechanical delay, versus controls (P <0.05 for all). There was a progressive increase of Pwave dispersion with increasing extent of calcification (P <0.05). Similarly, there was a progressive increase of lateral PA interval, inter-atrial and intra-atrial electromechanical delay with increasing extent of calcification (P <0.05 for all).Conclusions Patients with mitral annulus calcification had increased Pwave dispersion and electromechanical delay, versus matched controls. Pwave dispersion and electromechanical delay increased progressively with increasing extent of calcification.