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Tetralogy of Fallot (TOF)

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TOF-Definition

A congenital heart defect (CHD) which is

classically understood to involve four

anatomical abnormalities (although only three

of them are always present).

It is the most common cyanotic heart defect,

representing 55-70%, and the most common

cause of blue baby syndrome.

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Component

A. Pulmonary stenosis

B. Overriding aorta

C. Ventricular septal defect(VSD)

D. Right ventricular hypertrophy (RVH)

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A. Pulmonary valve stenosis

Valvular heart disease in which outflow of

blood from the right ventricle of the heart is

obstructed at the level of the pulmonic valve.

reduction of flow of blood to the lungs.

80% of right ventricular outflow tract

obstruction.

causes: congenital heart disease, rheumatic

heart disease or a malignant carcinoid tumor.

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Symptoms

Jugular venous distension, cyanosis (usually

visible in the nail beds), right ventricular

hypertrophy and general symptoms of

lowered oxygenation of the blood.

sudden fainting or dizziness if exercised too

much, an enlarged liver (hepatomegaly) and

swelling in the legs (oedema).

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Evaluation

echocardiography

The degree of stenosis is typically determinedby the peak pressure gradient across thevalve. If the peak gradient across the valve isgreater than 50 mmHg, intervention isgenerally warranted. If the peak gradient is