Hey Lynn!
I'm sure the cardiologist just wants to go over the test with you. Both of my parents had heart problems and the doctor's made absolutely certain they had immediate care. If there was something wrong, they would've told you and wanted you in right away - not make an appointment.
My mother was on a heart transplant list because the bottom of her heart had actually died! They gave her a new medication to keep her heart going while she was on the list and it actually healed her heart completely! This amazes me! I am terrified of cardio problems and I have to remind myself that there are amazing things doctor's can do with heart issues these days.
-IF- something is wrong, there are many, many things that can be done for you. Try not to worry about it. See your cardiologist and put your fears to rest.