Truncus arteriosus


Truncus arteriosus anatomy
  • A cyanotic congenital heart defect
  • Blood is pumped through a single truncal valve into a truncal artery which gives rise to the aorta and the pulmonary arteries
  • Associated with large VSD in most patients
  • Incidence ranges from 6 to 10 per 100,000 live births, accounts for 4% of all congenital heart disease [1]


  • PVR is high in the newborn infant, so there is little left to right shunting at birth
  • Over first several weeks of life, PVR drops, left to right shunting increases, leading to heart failure
  • Mixing of systemic and pulmonary blood leads to mild to moderate cyanosis
  • Pulmonary vascular obstructive disease may develop in surgically uncorrected patients

Clinical Features

  • Most present within the first weeks of life with

Differential Diagnosis

Congenital Heart Disease Types


  • ECG
    • May be normal
    • May have evidence of left or right ventricular hypertrophy
  • Chest x-ray
    • Enlarged cardiac silhouette
    • Increased pulmonary vascular markings
    • May see absent thymus in patients with TA associated with DiGeorge syndrome
  • Echocardiography



  • Admit

See Also

External Links


  1. Reller MD. Prevalence of congenital heart defects in metropolitan Atlanta, 1998-2005. J Pediatr. 2008;153(6):807-13.
  2. Knipe K et al. Cyanotic congenital heart diseases. Radiopaedia.
  3. Thompson LD. Neonatal repair of truncus arteriosus: continuing improvement in outcomes. Ann Thorac Surg. 2001;72(2):391-5.