Pulmonary-to-systemic shunt

A pulmonary-to-systemic shunt is a cardiac shunt which allows, or is designed to cause, blood to flow from the pulmonary circulation to the systemic circulation. This occurs when: A pulmonary-to-systemic shunt functions as follows:
 * 1) there is a passage between two or more of the great vessels; and,
 * 2) pulmonic pressure is higher than systemic pressure and/or the shunt has a one-way valvular opening.
 * 1) right-to-left in the absence of arterioventricular discordance.
 * 2) left-to-right if the great vessels are transposed.