What is meant by nonspecific STT changes/exercise induced STT depression? In my internet research, it relates to a heart attack and cardiac injury. Is it possible that I had a heart attack, or could something else cause this ? (I'm 24, female, 120 pounds). Can something like stress or tachycardia or anxiety cause these changes temporarily? In October, My EKG was normal. I had three this month, all showing these changes. Now I'm having a cardiac catheter. i'm just really wondering what this could mean - what they might find. Anyone know anything about STT depression?