Case report:
A 26-year-old primigravida was referred for fetal echocardiography at 28 weeks gestation in view of suspicion of pulmonary stenosis and VSD on screening ultrasound. Fetal cardiac screening preformed at first and second trimester were reported normal. The apical 4-chamber view demonstrated dilated right atrium and to and fro flow across the TV. There was low pressure tricuspid regurgitation (TV PGmax 3.9mmHg).[Figure 1; Movie 1] The lateral 4-chamber view showed normal offsetting of the atrioventricular (AV) valves and the anterior tricuspid valve leaflet (ATL) was inserted to the anterior papillary muscle.[Movie 2] The 4-chamber view continuous sweep from posterior to anterior showed absent posterior tricuspid leaflet and partially deficient ATL. [Figure 2; Movie 3] Left ventricular outflow tract view showed a large VSD particularly restricted by thickened septal tricuspid leaflet (STL).[Figure 3; Movie 4 and 5] High short axis view of the fetal heart showed a large VSD in the conoventricular region.[Figure 4; Movie 6]The outflow tracts were normally related and the main pulmonary artery was smaller [MPA 4.6mm (Z score -2.4)] than the ascending aorta. There was antegrade flow across the pulmonary valve (Vmax 0.72 m/s). Low short axis view at AV valves showed a normal mitral valve(MV) and a tricuspid valve (TV) with absent posterior tricuspid leaflet [PTL].[Figure 5A; Movie 7] Parasternal long axis right ventricle inflow view showed absent PTL, deficient ATL and color Doppler demonstrated free TR. [Figure 5B and 5C; Movie 8] Four dimensional images were obtained using volume transducer probe CV 1-8A [Samsung W10 equipment]. 4-dimensional high definition transverse surface rendering of the fetal heart slightly above the level of AV septum revealed the anatomy of both the AV valves. The MV was normal and there was non coaptation of TV. The TV was dysplastic with completely absent PTL and deficient ATL. [Figure 6A-C; Movie 9]