Myocardial Infarction Flashcards
What is another name for myocardial infarction?
Heart attack
How does a myocardial infarction begin?
From the occlusion, or blockage, of a coronary artery
The areas of infarction are regional because?
The regions of blood flow are regional
Why is an ECG helpful for a myocardial infarction?
It helps to give the best view of the involved region causing the infarction.
What is the 1st electrical change associated with a myocardial infarction?
Peaking of the T waves
What is the 2nd electrical change associated with a myocardial infarction?
T-wave inversions
Are the electrical changes in the T-wave that are associated with a myocardial infarction reversible?
Yes, only if blood flow is restored.
What is the 3rd electrical change associated with a myocardial infarction?
Elevation of the ST segment
What is the mechanism behind the ST elevation during a myocardial infarction?
The cardiomyocytes closest to the epicardium become depolarized by cellular anoxic injury, but are still electrically coupled so a plateau occurs resulting in an elevated ST phase.
What else can bring on a brief moment of ST elevation (aside from an MI)?
Coronary artery spasms. Rapid reperfusion of blood fixes elevation.
If you have ischemia without cell death (or partial blockage of blood flow), how will this show up on the ECG? What is a patient symptom of this?
ST-segment depression and T-wave inversion. Patient experiences angina (chest pain).
If there is irreversible cell death, how does this show up on the ECG? What does this indicate?
Q-waves become really deep. This indicates an area of muscle that has become electrically silent.
In which leads would an inferior wall infarction with deep Q waves be?
Leads II, III, and aVF
In which leads would an anterior wall infarction with deep Q waves be?
Precordial leads (Leads V1 to V6)
Do ALL infarctions create Q-waves?
No
