Testing for Patent Foramen Ovale (Hole in the Heart)
Bubble contrast echocardiography
This test is used for patients who have a history of stroke, TIA, decompression illness and sometimes migraine to see if there is a hole in the heart. Dr Turner performs this in the out-patients department at the time of the consultation, avoiding repeat visits to the hospital.
An ultrasound scan of the heart is performed with the probe on the skin of the chest. This shows the structure of the heart. A small cannula (small needle) is placed in a vein in the arm and microbubbles are injected. These outline the right side of the heart, but should be absorbed by the lungs. We then ask the patient to undertake straining manoeuvres to see if any bubbles can be forced through a hole in the heart into the left side of the circulation.
If done in a reproducible way, this can estimate the size of a hole in the heart, as well as whether it is present or not.
Some hospitals perform a procedure called a transoesophageal echocardiogram which is less reliable for detecting PFOs and is also more invasive and more expensive. Therefore a transthoracic bubble contrast echocardiogram is what Dr Turner recommends, with only a small minority needing any additional testing.
During the video you can see the bubbles are predominantly on the left of the screen, but then a cloud of bubbles cross over to the left heart through a PFO. When shown how big his PFO was the patient answered “wow”.