A clinical, electrocardiographic and echocardiographic (M-Mode, 2D) study was performed to explain the causal relationship between mitral annular calcification and cardiac conduction disturbances. Forty-seven patients, 28 women and 19 men (mean age 69) with mitral annular calcification were studied. In 18 patients A-V and/or intraventricular conduction disturbances were present. In this study we have found: a greater incidence of posterior than anterior mitral annular calcification; the anterior mitral annular calcification is often associated with aortic valve calcification and ultimately the common association between anterior mitral annular calcification and conduction disturbances.