How is the disease diagnosed?

Diagnosis begins with the physical exam. A chest X-ray may reveal an abnormally shaped heart. A heart tracing, called an electrocardiogram or ECG, may also be abnormal. The provider may order an echocardiogram, which uses ultrasound waves to see the beating heart. This test can show most of the defects in the heart and how they affect the heart's function.

A special procedure called a cardiac catheterization may also be done. This procedure involves inserting a tube though the skin and into a blood vessel, usually in the groin. The tube can then be advanced through the blood vessel into the heart. A contrast agent can be squirted through the tube and pictures taken while it is inside the heart and main blood vessels. This can help better define the defects in the heart. This procedure also allows tools to be passed through the tube and into the heart. These tools can make special holes in the heart to improve circulation until surgery can be done.