Intracardiac Shunts: Diagnosis Make an Appointment Refer a Patient Ask a Question Reviewed by Andrew M. Freeman, MD, FACC, FACP (November 01, 2018) How Is an Intracardiac Shunt Diagnosed? Patent foramen ovales (PFO) and atrial septal defects (ASD) are often diagnosed by an ultrasound of the heart (echocardiogram), often with a saline bubble test. An echocardiogram allows for the visualization of the hole, determination of the direction of the shunt, and estimation of the amount of shunt. Other imaging tests include: transesophageal echo (TEE), cardiac CT and cardiac MRI (CMR). These may be done if an echocardiogram is inconclusive or if supportive information is required. Cardiac catheterization (and to a lesser extent, CMR) can be performed to give a more accurate estimation of the degree of shunt when the decision to treat is unclear. Intracardiac Shunts: Treatment Clinical Trials For more than 100 years, National Jewish Health has been committed to finding new treatments and cures for diseases. Search our clinical trials.