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Atrial Septal Defect Reference Guide

Atrial Septal Defect

This is an auscultation example of an atrial septal defect as heard at the pulmonic position. Atrial Septal Defect is a congenital condition associated with abnormal blood flow between the left atrium and the right atrium. Before birth there is a large connection between right and left atria. During development of the fetus the connection gradually disappears. However, in some cases the opening persists and is known as an atrial septal defect. Both the first and second heart sounds are split. The second heart sound splitting is fixed at 80 milliseconds. There is a brief diamond shaped murmur in early systole and another brief diamond shaped murmur in early diastole In the anatomy video you see an enlarged right atrium and right ventricle. You see turbulent blood flow across the tricuspid valve between the right atrium and the right ventricle (the diastolic murmur). This is caused by blood flow from the left atrium into the right atrium through the atrial septal defect. There is further turbulent flow into the pulmonary artery causing the systolic murmur.

Auscultation Sound From Lesson

auscultation sound from lesson

Patient Recording

patient heart or lung sound
Atrial Septal Defect

Patient Recording - Half Speed Playback

patient heart or lung sound
Atrial Septal Defect


Patient position
The patient's position should be supine.

Listening Tips

Systole:Diamond shaped, brief, early murmur
S2:Fixed splitting
Diastole:Diamond shaped, brief, early murmur

Waveform (Phonocardiogram)

Observe Cardiac Animation

Play the cardiac animation and look for an enlarged right atrium and right ventricle.

Authors and Sources

Authors and Reviewers


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Atrial Septal Defect | Description, Audio and Animations | #110
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