Abstract
In order to assess the performance of pulsed Doppler echocardiography and to examine the factors affecting its reliability for the diagnosis of ventricular septal defects, 51 patients, in whom angiographic studies had recently been performed, were investigated before and after operation by this technique. The diagnosis was correct in all cases with left-to-right shunt, when the defect was located either in the upper muscular or in the infracristal portion of the septum, even when pulmonary hypertension or additional cardiac malformations were present. Pulsed Doppler echocardiography did not differentiate between supracristal ventricular septal defects and obstruction of the right ventricular outflow. Apical muscular defects were never observed in our cases. Defects of the inlet portion were not localised by the method. In cases with bidirectional shunt, pulsed Doppler echocardiography failed to provide any diagnostic clue. When a right-to-left shunt was present, only in one case with membranous pseudoaneurysm could pulsed Doppler echocardiography provide an exact description of the haemodynamics before and after operation. In 12 of 22 patients with tetralogy of Fallot, pulsed Doppler echocardiography showed flow tracings possibly related to the septal defect. The site of defect and the extent and direction of intracardiac shunting seem to be the main factors affecting its diagnostic performance in ventricular septal defects.