A EKG test can determine if a cardiac event is in progress or if you have had one in the past. The EKG can give clues to determine if your chest pain is caused by an inflammatory progress or if it is due to inadequate blood flow to the heart. Normally your heart rate is fairly constant; your doctor will look for consistencies and variations in your heart rate and rhythm-which can help your doctor diagnose or rule out the presence of heart disease.
Your doctor can't tell how well your heart is working until it's put to the test. If you have heart disease—or if you're at risk—your doctor may want to examine your heart during exercise. The stress test can spot hidden problems with your heart.
I would guess that you will have a pre-stress test EKG done on Monday for a baseline to compare with your stress test.
Good Luck and I will be waiting to hear how things turn out for you.