Total anomalous pulmonary venous return

In total anomalous pulmonary venous return (TAPVR), the pulmonary veins incorrectly send blood to the heart's upper right chamber. That chamber is called the right atrium. As a result, oxygen-rich blood mixes with oxygen-poor blood, as shown in purple. In a typical heart, shown on the left, oxygen-rich blood flows from the pulmonary veins to the upper left chamber, also called the left atrium.