###Human: I have a 3 mm patent foramen ovale. Is treatment required? ###Assistant: Hi. Small PFO (patent foramen ovale) is usually silent but may cause a stroke or pulmonary embolism if thrombus travels across it from right to left or left to right respectively. Moreover, your report says aneurysm of 12 mm, that needs consideration. I would suggest transesophageal echo to study it in detail. Usually, PFO is closed by the device but an aneurysm may need surgery. So, I advise you to have a transesophageal echo done and then plan will be decided accordingly.