In a left to right shunt oxygenated blood flows across a defect into the lower pressure right heart. It is then directed to the pulmonary bed and is returned to the left atrium. Because of the increased volume load all chambers and vessels that are overloaded by the shunt dilate and hypertrophy. The pattern of vessels and chambers affected by a shunt is specific to particular types of shunt eg an atrial septal defect overloads the right atrium and right ventricle, a persistent ductus arteriosus overloads the left atrium and left ventricle, and a ventriculoseptal defect overloads both ventricles.
The magnitude of the left to right shunt is determined by a variety of factors:
Annotations allow you to add information to this page that would be handy to have on hand during a consultation. E.g. a website or number. This information will always show when you visit this page.