Tetralogy of Fallot

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