Right to left shunt across subaortic VSD – echocardiogram
Blue colour in colour flow mapping (Color Doppler) echocardiography indicates flow away from the transducer. In this case it is flow from the right ventricle to the left ventricle, across the large ventricular septal defect. This can be seen in VSD with shunt reversal and in tetralogy of Fallot. In this case the aortic override suggests tetralogy of Fallot, though a similar picture can be there in double outlet right ventricle as well. VSD: ventricular septal defect; IVS: interventricular septum; LV: left ventricle; AML: anterior mitral leaflet; LA: left atrium; Ao: aorta; Ao valve: aortic valve; RV: right ventricle. Such large subaortic VSD with aortic override can be seen in tetralogy of Fallot and double outlet right ventricle. A similar appearance can be seen with the subtruncal VSD in truncus arteriousus.