Atrial septal defect


Definition: Left to right shunt of blood because the pulmonary vascular resistance is low and the right ventricle is easily distened→considerable increase in right heart out flow.

Atrial septal defect (ASD) is a form of  congenital heart defect that enables blood flow between two compartments of the heart called the left and right atria . Normally, the right and left atria  are separated by a septum called the interatrial septum . If this septum is defective or absent, then oxygen -rich blood can flow directly from the left side of the heart to mix with the oxygen-poor blood in the right side of the heart, or vice versa.This can lead to lower-than-normal oxygen levels in the arterial blood that supplies the brain, organs, and tissues. However, an ASD may not produce noticeable signs or symptoms, especially if the defect is small.

Types:There are two types

  1. Osteum secondum.
  2. Osteum primum.

Clinical features:

  1. Asymptomatic(most children).
  2. Some parents give the H/O RTI of child.
  3. Arrhythmia
  4. Weakness

Physical sign: On CVS examination-

  1. Left parasternal heave (due to Rt ventricular dilatation)
  2. Heart sound: Loud wide & fixed splitting of
  3. Murmurs:
  • Systolic flow murmur over pulmonary area.
  • Diastolic flow murmur over tricuspid area.
  • Apical systolic murmur (in septum primum type with defective mitral valve causing MR)



X-ray chest:

  • Right venticular enlargement.
  • Prominent pulmonary artery.
  • Plethoric lung fields, abnormally small aorta.

Fluoroscopy: Expansile pulsation of pulmoanry arteries.


  • Right axis deviation (in septum secundum type)
  • Left axis deviation (in septum prium type)


  • Pulmonary aterial dilation.
  • Demonstration of defect.
  • RV dilatation and hypertrophy.


  1. Pulmonary hypertension.
  2. Pulmonary embolism.
  3. Atrial flutter.
  4. Atrial fibrilation.
  5. CCF
  6. Brain abscess.
  7. Infective endocarditis.

Management:A significant ASD should be repaired before the age of 10 years or as soon as possible.If first diagnosed in adulthood:

  1. Direct suture.
  2. Pericardial patch.
  3. Synthetic

If disgnosed lately-no surgery.


  1. Davidson’s Principles and Practice of Medicine, 21st
  2. Wikipedia the free encyclopedia.

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