The affects of Ebstein's Anomaly depend on the position and functioning of the tricuspid valve. In mild cases, no symptoms may be present and there is no need for treatment. In more severe cases, the baby may become "blue," or cyanotic, because there is a significant amount of de-oxygenated blood crossing the atrial septal defect (ASD in diagram) to the left heart.

The "blueness" is caused by a blockage of the opening into the pulmonary artery (PA) and the leakiness of the tricuspid valve. The blockage is a result of the abnormal position of the tricuspid valve. The greater the blockage, the leakier the tricuspid valve and the more deoxygenated blood crosses the atrial septal defect into the left heart.  In some circumstances, the tricuspid valve is so insufficient that there is very little blood flow into the pulmonary resulting in profound cyanosis.

In some cases, an abnormal heart rhythm (an abnormal fast heart rate, tachycardia) may occur with Ebstein's Anomaly that requires medicine.