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Stages of an MI
Stages of an MI on ECG and Interventions
Question | Answer |
---|---|
What type of injury occurs during the first stage of an MI? | Acute Injury |
What will you see on the ECG during the first stage? | ST Elevations |
What period of time does the first stage represent? (What is happening to the heart during this time?) | Represents the period of time between the acute blockage of the lumen, and the start of tissue death in the part of the heart that is distal to that plug. |
How long does the first/Acute Stage of an MI last? | Approximately 6 hours |
Where will the ST Elevations occur on the ECG? | In ALL of the leads that monitor the affected area of the heart. |
What needs to be done during the first stage? | Give TPA if not contraindicated for patient. |
What type of injury occurs during the second stage of an MI? | Necrosis |
What will you see on the ECG during the second stage? | Big Q Waves (greater than a third of the total size of the QRS.)Maybe flipped T Waves. |
Where will you see the Big Q Waves on the ECG during the second stage (necrotic stage) of an MI? | In EVERY lead that monitors the affected area of the heart! |
If EVERY lead (that monitors an area of the heart) does not show changes r/t an MI, what might be occuring? | Artifact, iffy lead placement, anomoly... |
Can TPA be administered during the second stage? | No |
How long does the second stage last? | Hours to one day |
What is happening if you see ST Elevations and Big Q Waves on the ECG? | The patient is transitioning from the first/acute stage to the second/necrotic stage. |
What occurs during the third/resolution stage of an MI? | Development of scar tissue in the infarcted area. |
When does the third/resolution stage of an MI begin? | Roughly two weeks after the second/necrotic stage of the MI begins(or one week after it ends.) |
What will the ECG show during the third/resolution stage? | Persistent Q Waves and maybe flipped T Waves. |
How long will the Q Waves and flipped T Waves remain on an ECG? | Possibly forever. |
What may be happening with a patient who has had persistent flipped T Waves r/t an old MI, but now has upright T Waves? | Pseudonormaliztion of T Waves r/t new ischemia. |
What interventions need to occur during the first/acute stage? | tPA or cath lab (unless contraindicated) |
If your patient gets tPA, what changes should you expect to see on the ECG? | ST Elevations coming back down to baseline without development of Q Waves |
What interventions are needed during the second/necrotic stage of an MI? | Too late for tPA. Interventions are directed at the usual stuff: ectopy, changes in rhythm, blood pressure, all that. |