Partial anomalous pulmonary venous connection pathophysiology


 * Associate Editor(s)-In-Chief: Priyamvada Singh, M.B.B.S. [mailto:psingh@perfuse.org], Keri Shafer, M.D. [mailto:kshafer@bidmc.harvard.edu]; Assistant  Editor(s)-In-Chief: Kristin Feeney, B.S. [mailto:kfeeney@perfuse.org]

Overview
A congenital heart disease, like partial anomalous pulmonary venous connection, directly influences the normal mechanical, physical and biomechanical functioning of the heart. Partial anomalous pulmonary venous connection involves an exceeding ratio of the pulmonary blood flow to systemic blood flow.

Pathophysiology
The most important determinant of the ratio of pulmonary blood flow (Qp) to systemic flow (Qs) (the Qp/Qs ratio or the magnitude of the shunt) is the number of pulmonary veins that drain into the RA. The greater the number of pulmonary veins that drain into the RA}}, the greater the magnitude of the shunt. It has been speculated that when the proportion of returning [[pulmonary veins  that drain anomalously exceeds 50% of the pulmonary veins, then the anomaly is clinically significant. The position of the patient relative to the position of the anomalous pulmonary veins may also influence the magnitude of shunting. If a patient is standing, pulmonary blood flow is predominantly to the middle and the lower lobes of the lung. If there are a greater proportion of anomalous veins draining these portions of the lung, then standing can exacerbate the shunt.  Other noncardiac conditions may influence the magnitude of shunting. One such disease state is the scimitar syndrome or pulmonary venolobar syndrome.  In scimitar syndrome there is abnormal right-sided pulmonary venous drainage into the inferior vena cava. There is also malformation and/or hypoplasia of the right lung along with anomalous arterial flow to the right lung.