Bidirectional flow in congenital ventricular septal defect: a Doppler echocardiographic study.

The purpose of this study was to demonstrate the value of combined two-dimensional and pulsed Doppler echocardiography (echo) in localizing and recording bidirectional flow in congenital ventricular septal defect. Eight children, aged 8 months to 16 years, with clinical signs of a ventricular septal defect, underwent two-dimensional and pulsed Doppler echo study prior to cardiac catheterization. The ventricular septal defect was documented anatomically by two-dimensional echo in all eight patients. Flow patterns in systole and diastole through the ventricular septal defect and on both sides of the defect were carefully studied. In all eight children, systolic, high velocity, pathologic, left to right flow was documented when the sampling volume was positioned on the right ventricular side of the defect. When the sampling volume was positioned inside the defect, to and fro flow, left to right in systole and right to left in diastole, was observed. In children with moderate to large defects, the diastolic flow had a peak in early diastole. Increased pressure in the right ventricle over the left ventricle during the same period was demonstrated by cardiac catheterization and coincided with the Doppler flow. The direction of flow across the defect was affected by the size of the defect and the magnitude of the net shunt. Two-dimensional and pulsed echo Doppler were shown to be useful in demonstrating the ventricular septal defect and estimating its size and hemodynamic significance noninvasively.