How can an ekg show if ive had a heart attack? ive been having heart problems and my doctor wants to do an ekg. she says it will show if ive had a heart attack. how does it do that?

EKGs : Ekgs are great screening tools to look for major heart problems, and in particular can show evidence of an old heart attack. An ekg is a measurment of electrical activity in the heart and when you have a prior heart attack, the heart cells affected no longer work correctly, and this can show up as abnormal electical activity. Particularly very specific downward deflections (q-waves) in certain patterns can suggest this. But recognize that not all q-waves indicate prior heart attack. If your doctor is concerned, they may order a more confirmatory test.

Electrical signals: The ekg is a sensitive test of the heart's electrical system. Heart attacks damage the muscle which often shows up as abnormal looking signals on the ekg. Of course since it is sensitive, sometimes there are false positives. An abnormal ekg may need to be followed up by further testing. A normal ekg is pretty reliable.