A bubble echo is a straightforward test which is performed by a trained physiologist.
To begin the test, you’ll have a cannula (thin plastic tube) inserted into a vein in the back of your hand. A small amount of sterile saline with microscopic bubbles will then be injected. The bubble are best created by mixing the saline with a drop of your own blood. The protein in the blood holds the bubbles in the mixture. You’ll be asked to lie down on your left side with your left arm above your head.
As the bubbles from the injection flows through your bloodstream and into your heart, your physiologist will track them using an echocardiogram. If your heart is normal, the bubbles will only be visible in the right side. If bubbles appear in the left side of your heart, this indicates the valve is still open and you have an ASD or PFO. You will be asked to do certain manoeuvres to see if bubbles cross from right to left- sniffing, and Valsalva, straining down as if pushing hard.
A bubble echo usually takes around 30 to 45 minutes.