Flow Velocity Patterns across Atrial Septal Defects Recorded with Doppler Echocardiography

During a two-year period pulsed Doppler combined with two-dimensional echocardiography was used in evaluating patients for atrial septal defects. Blood flow velocities were recorded with pulsed Doppler in the right atrium along the atrial septum, across the atrioventricular and semilunar valves and when a shunt was detected also on the left side of the atrial septum. The typical flow velocity pattern most often seen is described and is related to the differences in pressure between the two atria during the cardiac cycle. Deviations from this velocity pattern are described and their hemodynamic significances discussed. Diagnosis and assessment of pulmonary hypertension from tricuspid and pulmonary flow velocities are described.