Tetralogy of Fallot
Introduction
-Tetralogy of Fallot (TOF) is the most common form of cyanotic Congenital heart disease
-it is associated with trisomy 21
–it has 4 anatomic components:
1.ventricular septal defect
2.right ventricular hypertrophy
3.pulmonary stenosis
4.overriding aorta
-It results in not enough blood going to the lungs to get oxygen, and the oxygen-poor blood is pumped to the rest of the body
Symptoms & Signs
-Clinical presentation depends on the degree of RV outflow obstruction
-Most present by 6 months of age; -right to left shunt causes cyanosis, hypoxemia (blue illness); Baby ‘turning blue’ with feeding or crying, failure to thrive
‘Tet spells’: cyanotic episodes with deep breathing, irritability, prolonged crying, child squats to interrupt the spells
-Harsh crescendo-decrescendo systolic ejection murmur best heard at the left upper sternal border (due to RVOT obstruction), single second heart sound
-Most common residual defect after TOF surgery: pulmonary regurgitation
Diagnosis
ECG: The ECG reveals RVH and right axis deviation; in repaired tetralogy, there is often a right bundle branch block pattern.
Chest X-ray: Boot-shaped heart (coeur en sabot sign)
Echocardiogram: Delineates TOF and quantifies degree of RV outflow obstruction
Cardiac MRI and CT can quantitate both the pulmonary regurgitation and the RV volumes.
Treatment
-Surgical repair is the definitive treatment of choice
-most adult patients have had surgical repair,
-The goal of surgical repair is to alleviate the pulmonary stenosis and close the VSD