Tricuspid atresia is a cyanotic congenital cardiac anomaly which is characterised by agenesis of the tricuspid valve and right ventricular inlet. There is almost always an obligatory intra-atrial connection through either an ASD or patent foramen ovale (PFO) in order for circulation to be complete 5. A small VSD is often also present. In a proportion of cases, tricuspid atresia may also be associated with transposition of great arteries (TGA).
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Clinical presentation
Presentation is in the neonatal period if not diagnosed antenatally, with progressive cyanosis, which is classically worse when crying 7.
ECG
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giant (>5 mm) P waves 6
with peaked morphology in lead II
exaggeration of right atrial enlargement morphology
referred to as "Himalayan P waves"
extreme axis deviation
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high left ventricular voltage (HLVV)
left ventricular hypertrophy voltage criteria
Pathology
It results from an unequal atrioventricular canal division and the right ventricle is typically hypoplastic.
Associations
Recognised extra-cardiac associations include:
absent spleen: asplenia
Radiographic features
Plain radiograph
Chest radiographic features may vary depending on the presence and extent of a ventricular septal defect or transposition of the great arteries. May demonstrate decreased pulmonary vascularity (i.e. oligaemic appearance). Cardiac size may be normal or enlarged.
Echocardiography/ultrasound
Usually the 1st line imaging modality in utero. It allows direct visualisation of the anomaly.
CT and MRI
Allows direct visualisation of the anomaly and may typically show a fatty and/or muscular separation of the right atrium from the right ventricle. Cine MRI can offer functional information in addition to anatomy.
Treatment and prognosis
Treatment is surgical. Initially a shunt is placed to increase pulmonary blood flow (e.g. Blalock-Taussig shunt). Definitive repair is with a Fontan procedure (which has several indications but was first described to treat tricuspid atresia 8). Patients successfully corrected can live into adulthood.