Cross-sectional echocardiography in the diagnosis of atrioventricular septal defect.

Between 1983-1988 cross-sectional echocardiography was performed in 63 patients having an atrioventricular septal defect with common atrioventricular orifice. We excluded from this study all those patients with separate right and left orifices ("ostium primum" defects), those with isomerism of the right and left atrial appendages, those with univentricular atrioventricular connexions and those with discordant atrioventricular and ventriculo-arterial connexions. Parasternal long- and short-axis views, apical 4-chamber views and subcostal long-axis views were employed in all patients. In the last 26 cases, we also obtained the subcostal short-axis view. Nineteen patients showed ventricular dominance, with the right ventricle being dominant in 15. Ten patients had an associated defect in the oval fossa, while the atrial septum was partially or completely absent in the other 53. A ventricular septal defect was observed in all, but it was small in 10 and multiple in 2. Attachments of the superior and inferior bridging leaflets to the crest or the right side of the ventricular septum were seen in 32 cases. The inferior leaflet was hypoplastic in 19 patients. There was narrowing of the left ventricular outflow tract in 8 patients, and obstruction of the right ventricular outflow tract in 3. Abnormal attachment of the right portion of the common valvar orifice was present in 2 cases. A solitary papillary muscle supporting the left ventricular component of the common valve was seen in 6 cases producing a parachute-like arrangement. Our study shows that cross-sectional echocardiography is an excellent technique for the analysis of this anomaly.