Causes and Diagnoses

Causes and Diagnoses of Patent Foramen Ovale

When a baby is born and their lungs start to work, the pressure inside their heart normally causes the foramen ovale to close. The patent foramen ovale may not close for a year or two after birth. In some cases, it never closes. This results in a PFO. Sometimes a PFO occurs with other heart problems. It is not known what causes PFO. There are also no known risk factors.


If you have had a stroke without warning or risk factors, a cardiologist at Northwestern Medicine may do an ultrasound of the heart (echocardiogram). This can show if you have a PFO.

Once you are diagnosed, Northwestern Medicine neurology and interventional cardiology teams will work with you to decide the best treatment options.