Tetralogy of Fallot
Definition
The combination of four defects: (1) large, overriding aorta, (2) peri-membranous ventricular septal defect, (3) pulmonary stenosis, and (4) right ventricular hypertrophy. The pulmonary stenosis may be valvular, subvalvular (infundibular), supravalvular, sub-infundibular, atretic, or any combination.
Signs and Symptoms
- Cyanosis and cyanotic spells
- Squatting
Shunt
- Due to the obstruction at the pulmonary level, blood shunts right to left out to the aorta
Cardiac Auscultation
- A harsh midsystolic murmur with a systolic thrill at the left midsternal border
- Single S2
- Early ejection sound
Electrocardiogram
- Right ventricular hypertrophy
- Left ventricular hypertrophy
Chest X-ray
- Boot shaped heart
- Right-sided aortic arch
Treatment
- Repair ventricular septal defect and pulmonic stenosis
M-Mode
- Limited, overriding aorta
2-D
- Parasternal long-axis view demonstrates overriding aorta, ventricular septal defect and right ventricular hypertrophy
- Parasternal short axis view of the aortic valve demonstrates pulmonic stenosis
- Evaluate pulmonary and coronary artery anatomy
Doppler
- Localize the region of stenosis with PW Doppler
- Determine the maximum instantaneous pressure gradient across the pulmonic stenosis with CW Doppler
Post-Surgical
- Evaluate ventricular septal defect repair
- Determine the presence and severity of pulmonary regurgitation
- Evaluate right ventricular hypertrophy