Right Ventricular Volume Overload Caused by “Aorta” to Right Heart Shunt: Echocardiographic Observations

Abstract

Right ventricular volume overload produces an enlarged right ventricle and paradoxical motion of the interventricular septum on the echocardiogram. We have observed a hitherto undescribed cause of the characteristic right ventricular volume overload pattern on the echocardiogram, caused by aorta to right heart shunting. Two patients had persistent truncus arteriosus and truncal valve incompetence. One patient had rupture of a sinus of Valsalva into the right atrium. In the two patients with truncus arteriosus, the anterior wall of the truncus was noted to be anterior to the interventricular septum, i.e. there was overriding of the septum. We conclude that “aorta” to right heart shunt should be included in the differential diagnosis of the echocardiography pattern of right ventricular volume overload. The association of this pattern with overriding of the “aorta” in a cyanotic patient may be a clue to the diagnosis of truncus arteriosus.