Diagnosis of tetralogy of Fallot almost always occurs during pregnancy or early infancy. In extremely rare cases, it is first diagnosed in adults. Adult patients will need ongoing diagnostic tests to measure how well their heart works and to check for possible problems. In addition to blood tests, diagnosis may include cardiac imaging.

A chest X-ray takes pictures of your heart, lungs and arteries and can reveal signs of heart disease, such as enlarged areas or calcium deposits in your heart and fluid in your lungs.

An echocardiogram records activity of the heart using high-frequency sound waves, or ultrasound. A technologist called a sonographer conducts this test by applying gel to your chest that makes it easier for sound waves to reach your heart. The sonographer will then wave a transducer across your chest to send sound waves to your heart. The echo created by those waves is translated into images of your heart as it beats.

Providing information about your heart’s electrical activity, an electrocardiogram can help your provider understand your heart rate and whether you have an arrhythmia. Alternatively, your provider might ask you to wear a monitor for a day or two to record how well your heart’s circuitry works.

Cardiac magnetic resonance imaging (MRI) uses magnets to create detailed images of the heart’s structure and show blood flow and heart valve function. Using cardiac MRI, your physician can diagnose heart valve disease by evaluating leaky or narrowed valves.

A stress test measures certain indicators of heart health while stressing your heart through exercise or medications. Certain heart conditions are easier to diagnose when your heart is under stress, and a stress test gets your heart beating hard under controlled conditions.

During a cardiac catheterization, a thin tube called a catheter is maneuvered from an opening in the groin to the heart. The catheter can measure pressure and blood flow. Some types of heart problems can be repaired from within the blood vessels during a cardiac catheterization procedure.