Fetal echo

I'm 21 weeks pregnant with my first baby and have a congenital heart disease.... since I have heart problems, they will check my baby's heart (fetal echocardiogram) through ultrasound. I'm super nervous, I don't want my child to have heart problems too :( please take a few seconds of your day to say a quick prayer for him, the test will be next Wednesday. Has anyone ever done this test before? If so, how did that go?