is where an ultrasound
machine is used to look at the pumping action of your heart.
It's the same machine used to look at unborn babies in pregnant women. The worst thing they do to you is smear that jelly stuff on your skin. :)
They might be looking for something called mitral valve regurgitation, which can usually be diagnosed with an echocardiogram. I don't really know for sure, but you can always call your doctor if you have any questions.
Good luck. :)