PANCE Blueprint Cardiology (13%)

Tetralogy of Fallot

Patient will present as → a 2-week-old newborn brought to the ER by his mom who reports a sudden loss of consciousness during feeding and with crying. She also has noticed that the infant's lips have turned blue on three occasions during feeding.  blood pressure is 75/45 mmHg, a pulse is 170/min, and respirations are 44/min. A grade 3/6 harsh systolic ejection murmur is heard at the left upper sternal border. A CXR shows a small boot-shaped heart and decreased pulmonary vascular markings.

Tetralogy of Fallot is the only cyanotic congenital heart disease on the NCCPA blueprint!

Cyanotic heart disorder that is characterized by four defects (tetra = 4) that together cause oxygen-deficient blood to flow out of the heart and into the rest of the body

Four features: PROVe

  1. ulmonary Stenosis
  2. R ight ventricular hypertrophy
  3. verriding aorta
  4. V entricular septal defect

The pulmonary stenosis causes a right to left shunt through the VSD, thereby causing cyanosis.

  • TET SPELLS: hypercyanotic episodes that develop during crying or feeding

Tetralogy of Fallot

What is the classic chest x-ray finding in Tetralogy of Fallot?
Chest x-ray classically shows boot-shaped heart

Murmur is classically described as a harsh systolic ejection murmur heard best at the left sternal border

  • Echocardiography is the diagnostic modality of choice. This test can clearly define the four abnormalities as well as provide important information about aortic arch anatomy
  • A chest x-ray classically shows a boot-shaped heart
  • EKG may show enlarged RA and RV. Check the width of QRS annually via ECG to reduce the risk of sudden cardiac death
  • Cardiac catheterization may be required in some patients to fully define the anatomy
  • Squatting decreases the cyanosis in tetralogy of Fallot

Treatment is surgical. Most patients have surgery within the first year of life

  • Twenty-year survival rates after surgery are above 80%. The most common causes of death are sudden cardiac death and heart failure
  • Complications after surgery include arrhythmias, pulmonary regurgitation, residual outflow obstruction, and heart failure

osmosis Osmosis
Tetralogy of Fallot


Tetralogy of Fallot is a congenital birth defect of the heart leading to cyanosis. It presents with up to 4 different heart defects, and is the most common cause of blue baby syndrome. The four pathologies in this disease are pulmonary infundibular stenosis, right ventricular hypertrophy, overriding aorta, and ventricular septal defect.

Play Video + Quiz

Question 1
A 10-month-old girl was admitted to the hospital for cardiac catheterization. Her history included cyanosis noted at about 6 weeks of age, increasing over the last 7 months and becoming more severe with crying or physical activity. The chest x-ray demonstrates a "boot shaped heart" A presumptive diagnosis of tetralogy of Fallot (TOF) was made on admission. TOF has 4 components, which of the following below is not part of the diagnosis?
Pulmonary valve stenosis
See E for explanation
See E for explanation
Overriding aorta
See E for explanation
Right ventricular hypertrophy
See E for explanation
Question 1 Explanation: 
In 1888, Fallot described a congenital heart defect composed of four characteristics (a) large ventricular septal defect (VSD) (b) right ventricular outflow obstruction (pulmonary valve stenosis) (c) overriding aorta (d) right ventricular hypertrophy. The main characteristic of TOF is cyanosis. Hypercyanotic spells or "tet spells" are paroxysmal episodes in which the cyanosis acutely worsens. Crying, feeding, or defecating can bring on these episodes.
Question 2
A 12 month-old child with tetralogy of Fallot is most likely to have which of the following clinical features?
Chest pain
Chest pain is not a feature of tetralogy of Fallot.
Convulsions are occasionally seen as part of severe hypoxic spells in infancy rather than a feature of tetralogy of Fallot.
Palpitations are uncommon in tetralogy of Fallot.
Question 2 Explanation: 
Cyanosis is very common in tetralogy of Fallot.
There are 2 questions to complete.
Shaded items are complete.

References: Merck Manual · UpToDate

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