Tetralogy of Fallot with pulmonary stenosis (fetal echocardiogram)

Case contributed by Cathy Cluver

Presentation

Tertiary review for fetal echocardiography.

Patient Data

Age: Second trimester
Gender: Female

Four chamber view (4CV)

ultrasound

Four chamber view demonstrates a perimembranous VSD. Right ventricular hypertrophy may or may not be seen on the antenatal 4CV.

Left ventricular outflow tract (LVOT) or 5 chamber view

ultrasound

The left ventricular outflow tract is seen to be overriding the ventricular septum. This in association with the ventricular septal defect is referred to as a malaligned VSD.  The color images demonstrate filling of the LVOT from both the left and right ventricles with more than 50% of flow coming from the left ventricle.  The LVOT is dilated. 

Also, note the left axis deviation.

Right ventricular outflow tract (3 vessel view)

ultrasound

In the scenario of TOF with pulmonary stenosis, the three-vessel view shows the narrow right ventricular outflow tract and dilated aorta.

This is in contrast to a TOF with pulmonary atresia, where the RVOT is absent in this view, and to a TOF with dysplastic pulmonary valve syndrome, where there is a dilated RVOT with turbulent flow.

Three vessel - trachea (3VT) view

ultrasound

In the scenario of TOF with pulmonary stenosis, the 3VT view demonstrates a narrow duct with forward flow.  

This is in contrast to a TOF with pulmonary atresia, where there is reverse flow in the duct, and to a TOF with dysplastic pulmonary valve syndrome, where the duct is typically absent.

Case Discussion

There are a number of different subtypes of tetralogy of Fallot: Tetralogy of Fallot with pulmonary stenosis (75%), Tetralogy of Fallot with pulmonary atresia (20%) and dysplastic (absent/ring) pulmonary valve syndrome (5%).

This case demonstrates the typical findings on the standard fetal echo views in a case of tetralogy of Fallot with pulmonary stenosis.

 

Images courtesy of Dr Simon Meagher

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