Tetralogy of Fallot

Consists of a triad of

1. Ventricular Septal Defect as large as aortic value annulus
2. Overriding of aorta
3. Right ventricular outflow tract obstruction / Pulmonary Stenosis
4. Right ventricular hypertrophy

Clinical Presentation

• Symptoms develop anytime after birth
• Clubbing and Cyanosis
• Mild ( RVOT ) obstruction – Presents with an isolated murmur ( Pink tetralogy )
• Severe obstruction –
  • Presents with cyanosis, a prominent parasternal heave
  • S2 – late and soft P2 ( inaudible), A2 is the single and audible sound

Cyanotic spells

• Dyspnea on exertion ( like excessive crying ) or in morning
• The toddlers assume a squatting position after physical exertion
• Child starts crying → Becomes more hyperpnoeic → Cyanosis deepens ( child becomes bluer ) → Syncope → Severe spells may lead to convulsions

Physical Examination

• Cyanosis and Clubbing present
• Slight prominent a waves in JVP
• Normal S1, Single S2 heard
• Ejection systolic murmur

Investigations

ECG

• RVH and Right axis deviation
• T waves are usually inverted
• P pulmonale may be present

Chest X ray – Boot shaped heart

For confirmation – ECHO, Cardiac catheterization in specific cases

Hemodynamics

Complications

• Pulmonary stenosis becomes severe with age
• Dyspnea and increasing exercise intolerance.
• Anemia
• Cardiac enlargement & congestive cardiac failure
• Patients prone to infective endocarditis
• Anoxic infarction in the central nervous system occurs leading to hemiplegia
• Hemiplegia can also occur due to paradoxical embolism to CNS and venous thrombosis
• Brain abscess
• Congested retina and papilledema

Treatment

For cyanotic spells –

• Oral Propranolol ( 0.5 – 1.5 mg / kg / dose)
• Iron supplementation

Surgery

Definitive

• Closure of VSD and relief of pulmonary stenosis
• Relief involves placement of transannular patch across the pulmonary value

Palliative

• Blalock- Taussig Shunt – Subclavian artery- pulmonary artery anastomosis using a Goretex graft
• Alternatives – Balloon dilatation of the pulmonary value or stenting of patent arterial duct

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