ABSTRACT
The loss of a normal offset between the A-V valves suggests the presence of an A-V canal defect—called the A-V septal defect—and this is associated with a 50%–60% risk of underlying chromosomal abnormalities. Asymmetry of the cardiac chambers usually reflects a structural problem in the A-V or outflow tract valves. Rare causes include anomalous venous drainage of the pulmonary veins where the drainage is into the right side of the heart rather than the left side of the heart in one or more veins. In routine screening of the fetal heart, one should ideally be able to extend views to check the outflow tracts and use color Doppler to assess the fetal heart thoroughly. Cardiomegaly by itself is an indicator for detailed fetal echocardiography and detailed fetal assessment of the hemodynamic state in the fetus. The fetal heart points to the left side with the majority of the heart lying in the left chest.
