This defect often remains undiagnosed during childhood, and even during adulthood. Later in life, however, symptoms may arise that make surgical repair necessary. These include dyspnea (breathlessness) in response to exertion, atrial arrhythmias (flutter or fibrillations), or, more rarely, right heart failure and pulmonary hypertension.

Adult patients who have not been operated on in childhood may need to undergo repair if right heart enlargement (dilalation) occurs. This will be recognized by a heart murmur or by echocardiography.

After repair, the patient may expect to remain free of adverse symptoms. Rarely, obstruction (stenosis) of the reimplanted pulmonary vein or veins may cause recurrent chest infections or other problems. Pulmonary hypertension may also occur and arrhythmias are sometimes experienced after surgery - a situation that increases in likelihood with the age at repair. Therefore it is important that all patients be examined regularly by a cardiologist throughout life.