Normally, this defect causes no negative symptoms and the child grows and behaves normally, without the need for medicine or surgical intervention.

The amount of blood carried by a single pulmonary vein is not significant enough to cause right heart dilation.

However, if 50% or more of the pulmonary veins enter the right side of the heart, or if an entire lung is drained by pulmonary veins into the right heart, surgical correction of the defect may be necessary. In such cases, the increased blood volume in the right heart can cause enlargement (dilatation) of the right atrium, right ventricle, and the pulmonary artery. Also, the child may tire easily with strenuous exercise.  If an atrial septal defect is present, the child could appear mildly cyanotic.