From the Guidelines
Tetralogy of Fallot (TOF) screening should be performed through targeted evaluation when suspected, using echocardiography as the definitive diagnostic test, and cardiac MRI for surgical planning, as recommended by the most recent guidelines 1.
Screening Recommendations
- Prenatal screening via fetal echocardiography is recommended for pregnant women with risk factors such as family history of congenital heart disease, maternal diabetes, or abnormal obstetric ultrasound findings, to be performed at 18-22 weeks gestation by specialists in maternal-fetal medicine.
- After birth, diagnosis is often prompted by clinical signs including cyanosis, heart murmur, or respiratory distress.
- Pulse oximetry screening is now standard for all newborns before discharge from the hospital and can help identify critical congenital heart defects including severe forms of TOF.
Diagnostic Tests
- Echocardiography is the definitive diagnostic test, which can visualize all four characteristic defects: pulmonary stenosis, ventricular septal defect, overriding aorta, and right ventricular hypertrophy.
- Cardiac MRI may be used for surgical planning and to assess the severity of pulmonary regurgitation and associated pathology.
Importance of Early Detection
- Early detection is crucial as TOF requires surgical correction, typically performed between 3-6 months of age, to prevent complications such as hypoxic spells, growth failure, and long-term cardiac dysfunction.
- The 30-year survival rate for TOF patients is > 90% with timely and appropriate treatment 1.
Follow-up Care
- Patients with repaired TOF should have at least annual follow-up with a cardiologist who has expertise in adult congenital heart disease (ACHD) 2, 3.
- Echocardiographic examinations and/or MRIs should be performed by staff with expertise in ACHD to monitor for residual abnormalities and complications 2, 3.
From the Research
Tetralogy of Fallot Screening
- Tetralogy of Fallot is one of the most common forms of cyanotic congenital heart disease, characterized by four main anatomic features: a large ventricular septal defect, overriding aorta, right ventricular outflow obstruction, and right ventricular hypertrophy 4.
- The refinement of fetal screening and echocardiography has led to an increase in prenatal diagnosis, allowing for prenatal counseling and prediction of the postnatal course and surgical repair 4.
- Echocardiography plays a crucial role in the follow-up of patients with tetralogy of Fallot, particularly in adulthood, where residual anatomic and hemodynamic abnormalities are common 5, 6.
- The essential echocardiographic features of tetralogy of Fallot can be demonstrated in infants, children, and fetuses, including subpulmonary stenosis, ventricular septal defect, aortic override, and right ventricular hypertrophy 7.
Diagnosis and Treatment
- Prenatal diagnosis of tetralogy of Fallot, along with the recognition of extracardiac anomalies and genetic abnormalities, sets the framework for prenatal counseling and can help predict the postnatal course and surgical repair 4.
- Full surgical repair within the first year of life, either primary or after a palliative procedure, is the mainstay of therapy for tetralogy of Fallot 4.
- Adult patients with repaired tetralogy of Fallot require careful follow-up, as mortality starts to increase 25 years after surgery, and residual anatomic and hemodynamic abnormalities are common 5, 8.
Echocardiographic Evaluation
- Echocardiography is essential for the evaluation of tetralogy of Fallot, including the assessment of the ventricular septal defect, overriding aorta, pulmonary stenosis, and right ventricular hypertrophy 6, 7.
- Multiple echocardiographic techniques can be used to evaluate patients with tetralogy of Fallot, including the assessment of pulmonary valve morphology and the main and branch pulmonary arteries 7.