Related Subjects:
|Congenital Acyanotic Heart Disease
|Congenital Cyanotic Heart Disease
|Cardiac Embryology
|Cyanosis - Central and Peripheral
|Down's syndrome (Trisomy 21)
|Tetralogy of Fallot
|Patent Foramen Ovale (PFO)
|Ventricular Septal defect (VSD)
|Tricuspid Atresia
|Transposition of the great arteries (TGA)
💙 Tricuspid Atresia is a rare congenital heart defect where the tricuspid valve fails to develop, blocking blood flow from the right atrium to the right ventricle.
➡️ This results in an underdeveloped (hypoplastic) right ventricle and reduced pulmonary blood flow.
⛔ Without intervention, survival is not possible, as oxygenated and deoxygenated blood cannot mix effectively.
📖 About
- Important cause of cyanotic congenital heart disease.
- Survival depends on alternative pathways for blood mixing (ASD, VSD, PDA).
🧬 Aetiology
- Absent functional tricuspid valve → ineffective or hypoplastic RV.
- Impaired blood flow to lungs causes systemic hypoxaemia.
🩺 Clinical Features
- 🌫️ Cyanosis: Blue lips/skin soon after birth.
- 😮💨 Difficulty breathing: tachypnoea, respiratory distress.
- 🥛 Poor feeding & failure to thrive.
- 😴 Fatigue and lethargy.
- 🔊 Heart murmur (from associated VSD/PDA flow).
- 👉 Clubbing: chronic hypoxaemia leads to finger clubbing later in infancy/childhood.
🔎 Investigations
- Echocardiography: Diagnostic test of choice – shows absent tricuspid valve, RV hypoplasia, flow patterns.
- ECG: Right atrial enlargement, left ventricular hypertrophy (since LV pumps systemic and pulmonary flow).
- Chest X-ray: Cardiomegaly, reduced pulmonary vascular markings.
- Pulse oximetry: Persistent desaturation.
- Cardiac catheterization: Defines anatomy, pressures, and used before interventions (e.g. shunt).
- MRI: Used when echo is inconclusive for detailed anatomy.
- Genetic testing: To detect syndromic associations.
🛠️ Management
| Management Option |
Description |
Comments |
| 💉 Prostaglandin Infusion |
Keeps ductus arteriosus open (PGE1). |
Immediate emergency stabilisation to allow pulmonary blood flow. |
| 🕳️ Atrial Septostomy |
Enlarges ASD for atrial mixing. |
Improves systemic oxygenation in neonates. |
| 🔗 Blalock–Taussig Shunt |
Shunt from subclavian artery → pulmonary artery. |
Palliative, improves pulmonary flow until definitive repair. |
| ↔️ Bidirectional Glenn |
SVC connected to pulmonary arteries (blood from upper body flows directly to lungs). |
Usually performed at 4–6 months; step towards Fontan. |
| 🔄 Fontan Procedure |
IVC connected to pulmonary arteries → systemic venous blood bypasses heart. |
Final stage palliation (18 months–4 years). Provides long-term survival pathway. |
| 📅 Long-term Follow-up |
Monitoring for arrhythmias, heart failure, protein-losing enteropathy. |
Lifelong cardiology follow-up is essential post-Fontan. |
💡 Teaching Pearl:
Unlike TGA, where circulation is parallel, in tricuspid atresia the LV handles both systemic and pulmonary flow.
📊 ECG clue: left ventricular hypertrophy is typical (unlike most cyanotic CHDs which show RVH).
