How is an ASD diagnosed?

Tests to check for an ASD include:

  • Electrocardiogram (ECG/EKG) – a graph of the heart’s electrical activity (heartbeat)
  • Chest X-ray to check the size of the heart and the blood vessels that supply blood to the lungs
  • Transthoracic echocardiography/Doppler examination – an ultrasound image of the heart combined with measurements of blood flow to check the heart’s structure and see how well it is working.
  • Transesophageal echocardiography (TEE) Doppler examination – an ultrasound taken through the esophagus is used to get a better picture of the atria and more details about the size and shape of the ASD. A TEE helps the doctor can also be used to check the heart valves.
  • Intracardiac echocardiography (ICE)/Doppler examination – an ultrasound taken inside the heart. A tiny camera (echo probe) is sent to the heart through a peripheral vein. The test shows the size and shape of the defect and the direction of the blood flow across it. This study is often used during percutaneous (nonsurgical) repair of the defect.
  • Right heart catheterization – a small, thin tube (catheter) is inserted into the heart through a peripheral vein. Pressures and the amount of oxygen in the blood (oxygen saturations) are measured in each chamber of the heart. The oxygen levels determine how much blood is flowing across the ASD. Your doctor may also use a tiny balloon at the end of the catheter or a special dye to check the size of the defect (atrial angiogram).
  • Left heart catheterization – during this procedure, a special dye is sent into the blood vessels of the heart through a catheter (angiography). The test can check for coronary artery disease (hard, narrow arteries).

Last reviewed by a Cleveland Clinic medical professional on 07/17/2019.



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  • American Heart Association. About Congenital Heart Defects Accessed 3/12/2015.
  • Centers for Disease Control and Prevention. Facts about Congenital Heart Defects Accessed 3/12/2015.
  • National Heart, Lung, and Blood Institute. What are Congenital Heart Defects? Accessed 3/12/2015.
  • Hirsh JC, Devaney EJ, Ohye RG, Bove EL. Chapter 19B. The Heart: II. Congenital Heart Disease. In: Doherty GM. eds. CURRENT Diagnosis & Treatment: Surgery, 13e. New York, NY: McGraw-Hill; 2010.

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