Usually 1 Pulmonary Vein, rarely all pulmonary vein
Partial anomalous pulmonary venous connection (PAPVC) is a rare congenital cardiac defect. As the name suggests, in PAPVC, the blood flow from a few of the pulmonary veins return to the right atrium instead of the left atrium. Usually, a single pulmonary vein is anomalous. Rarely, all the veins from one lung are anomalous.
PAPVC from the rt lung is twice as common as PApVC from left lung. The most common form of PAPVC is one in which a rt upper pulmonary vein connects to the right atrium or superior venacava

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