Patent Foramen Ovale (PFO)
A patent foramen ovale, or PFO, is a special type of hole between the upper chambers of the heart. While an Atrial Septal Defect is always considered a structural abnormality in the heart, everyone at birth has a PFO. In about 75% of patients, the PFO closes on its own after birth, but about a quarter of people may have persistent, although usually very small, amounts of blood which can go across this hole. PFOs are very common: in most patients they are not clinically significant, and do not require specific therapy. The one exception is that in rare cases, a PFO can be a risk factor for stroke.
Symptoms of Patent Foramen Ovale
PFOs usually are benign and do not cause symptoms or require specific treatment. However in a very small minority of patients, small blood clots can form in the legs, get passed through the PFO, travel to the brain and cause a stroke, similar to an Atrial Septal Defect.
Testing for Patent Foramen Ovale
A bubble study is performed with echo, where IV fluid is agitated in a syringe to create microbubbles. The IV fluid is then injected into a vein, and the bubbles can be visualized in the right chambers of the heart. It bubbles cross into the left chambers of the heart, it is suggestive of an abnormal communication between the chambers of the heart. This is particularly useful when diagnosing a PFO: these holes are small enough that they will not cause abnormal murmurs, ECGs, chest x-rays, or an obvious abnormality on echo.
Treatment for Patent Foramen Ovale
If a PFO does not cause symptoms, it does not require any therapy. Patients, especially younger patients under the age 60, who have suffered a stroke should be evaluated for a PFO; this is particularly true if they do not have another cause of, or risk factors for, stroke. If the PFO is felt to be a possible contributor to the stroke, patients may be treated with aspirin or blood thinners such as warfarin. Alternatively, some patients may be considered for a closure device — similar to an ASD closure device — which is inserted through a catheter in the groin.