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For further information, see CMDT Part 10-08: Tetralogy of Fallot

Key Features

Essentials of Diagnosis

  • Five features are characteristic:

    • Ventricular septal defect (VSD)

    • Concentric right ventricular hypertrophy (RVH)

    • Right ventricular (RV) outflow obstruction due to infundibular stenosis

    • Overriding aorta (requires < 50% of the aorta to override the septum) in half

    • A right-sided aortic arch in 25%

  • Most adult patients have undergone surgical repair, usually with an RV outflow patch and VSD closure; if patch overrides the pulmonary valve annulus, pulmonary regurgitation is common

  • Physical examination may be deceptive after classic tetralogy repair, with severe pulmonary valve regurgitation often present if a transannular patch was used

  • Echocardiography/Doppler may underestimate significant pulmonary valve regurgitation; be wary if the RV is enlarged

  • Arrhythmias are common; periodic ambulatory monitoring is recommended

  • Serious arrhythmias and sudden death may occur if the QRS is wide or the RV becomes quite large or both

General Considerations

  • If there is an associated atrial septal defect (ASD), the complex is called pentalogy of Fallot

  • Pulmonary valve stenosis may also be present, usually due to either a bicuspid pulmonary valve or RV outflow hypoplasia

  • The aorta can be enlarged and aortic regurgitation may occur

  • If > 50% of the aorta overrides into the RV outflow tract, the anatomy is referred to as a double outlet RV

  • Two vascular abnormalities are common

    • An inconsequential right-sided aortic arch (in 25%)

    • Anomalous left anterior descending coronary artery from the right cusp (7–9%)

Clinical Findings

Symptoms and Signs

  • Most adult patients in whom tetralogy of Fallot has been repaired are relatively asymptomatic unless right heart failure or arrhythmias occur

  • Physical examination should check both arms for any loss of pulse from a prior shunt procedure in infancy

  • Jugular venous pulsations (JVP) may reveal

    • An increased a wave from poor RV compliance

    • A c-v wave due to tricuspid regurgitation (rarely)

  • The precordium may be active

  • P2 may or may not be audible

  • A right-sided gallop may be heard

  • A residual VSD or persistent pulmonary outflow or aortic regurgitation murmur may be heard

  • The insertion site of a prior Blalock or other shunt may create a stenotic area in the branch pulmonary artery (PA) causing a continuous murmur

  • Pulmonary arterial stenotic bruits may best be heard on the lateral chest wall


Imaging Studies

  • Chest radiograph shows

    • A classic boot-shaped heart with prominence of the RV and a concavity in the RV outflow tract

    • An enlarged and right-sided aorta

  • Echocardiography/Doppler

    • Establishes the diagnosis by noting the unrestricted (large) VSD, the RV infundibular stenosis, and the enlarged aorta

    • Provides data regarding the amount of residual pulmonary valve regurgitation if a transannular patch is present, RV and LV function, and the presence of aortic regurgitation in patients ...

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