Ultrasonic cardiography (UCG) shows that tachycardia tends to truncate or eliminate diastolic closing of the anterior leaflet of the miral valve (ALMV). This tendency is more promounced in miral stenosis. Atrial fibrillation and flutter are characterized by fine and coarse diastolic oscillations of the ALMV. In complete heart block the ALMV close rapidly after dissociated atrial contractions and the velocity of closure is unrelated to the phase of ventricular diastole.