Atrial septal defect: shunt physiology and consequences
THE CONTEXT
Differences in ventricular compliance explain the atrial shunt and the resulting enlargement of right-sided cardiovascular structures.
Shunt direction and enlargement
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The normal right ventricle is more compliant than the left ventricle.
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The passage describes blood passing through a patent foramen ovale from the left atrium to the right atrium, then to the right ventricle and pulmonary arteries.
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This flow produces gradual enlargement of the right side of the heart and the pulmonary arteries.
Later complications
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Pulmonary hypertension and shunt reversal sometimes complicate atrial septal defect.
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These complications are less common and tend to occur later in life than with other left-to-right shunts.