system
Given the following post, respond as if you're commenting on Reddit:
human
How can doctors tell if you've had a heart attack well after the event?

I had a family friend recently suffer a heart attack and she said that for a week she was feeling really bad and slightly disoriented. She went to the doctor and they said she had a heart attack earlier in the week. How do they determine that? Are there biological markers that stick around for a while? How long? Is something permanently changed in your body from that point?
gpt
One way a physician can tell someone had a cardiac event is by doing an electrocardiogram which can (not always) show changes in the waveforms.  Blood troponin levels (protein released if heart cells are damaged) can only be done in the first 24 hours after a suspected attack.  While damage to the heart is permanent, alternate pathways of circulation to the heart will develop over time if the patient survives without having a stent placed in the event of a blockage.   The patient's cardiologist should provide them with all necessary information, or the emergency physician for acute situations.