Partial anomalous pulmonary venous connection

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-In-Chief: Priyamvada Singh, M.B.B.S. [2], Keri Shafer, M.D. [3]; Assistant Editor(s)-In-Chief: Kristin Feeney, B.S. [4]

In partial anomalous pulmonary venous connection (PAPVC) with intact atrial septum a portion (hence the term partial) of veins return to the right atrium rather than the left atrium. As a result oxygenated blood returning form the lung returns to the venous system via the right atrium.

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-In-Chief: Priyamvada Singh, M.B.B.S. [2], Keri Shafer, M.D. [3]; Assistant Editor(s)-In-Chief: Kristin Feeney, B.S. [4]

Partial anomalous pulmonary venous connection (PAPVC) results the malformation of the heart during fetal development. Anatomically a PAPVC involves overcirculation of blood to the lungs through malconfigured pulmonary veins.

Anatomically, partial anomalous pulmonary venous connection (PAPVC) can involve a wide variety of connections. PAPVC from the right lung is twice as common as PAPVC from the left lung. The most common form of PAPVC is one in which a right upper pulmonary vein connects to the right atrium or the superior vena cava (SVC). This form is almost always associated with a sinus venosus type of atrial septal defect (ASD).

In addition to draining into the right atrium, the anomalous right pulmonary veins can also drain into the inferior vena cava. Similarly, the left pulmonary veins can drain into the innominate vein, the coronary sinus. More rarely, the left pulmonary vein can drain into the cavae, the right atrium, or the left subclavian vein.

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-In-Chief: Priyamvada Singh, M.B.B.S. [2], Keri Shafer, M.D. [3]; Assistant Editor(s)-In-Chief: Kristin Feeney, B.S. [4]

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.

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.

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-In-Chief: Priyamvada Singh, M.B.B.S. [2], Keri Shafer, M.D. [3]; Assistant Editor(s)-In-Chief: Kristin Feeney, B.S. [4]

Partial anomalous pulmonary venous connection is a rare congenital heart disease. There is a very low incidence rate. Prevalence is difficult to determine due to the asymptomatic nature of the disease.

Autopsy data suggests that partial anomalous pulmonary venous connection (PAPVC) has an incidence of 0.4-0.7%. Many of these autopsy cases were asymptomatic and as a result the clinical incidence of PAPVC is much lower.

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-In-Chief: Priyamvada Singh, M.B.B.S. [2], Keri Shafer, M.D. [3]; Assistant Editor(s)-In-Chief: Kristin Feeney, B.S. [4]

During diagnostic evaluation, it is important to recognize that signs and symptoms of partial anomalous pulmonary venous connection can be similar to other congenital heart diseases.

PAPVC is present in approximately 10% of patients with an ASD. Depending upon the hemodynamics and magnitude and direction of shunting, an ASD may either improve or exacerbate the shunting associated with a PAPVC. These two defects have a common embryologic origin. However, in contrast to PAPVC, in TAPVC all pulmonary venous return is to the right atrium.

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