Myocardial Infarction and Clinical Cases Flashcards
What qualifies as STEMI in men?
What about for women?
ST elevation of 2mm or greater at J point in V2-3
ST elevation of 1.5mm in absence of LVH or 1mm or more in 2 contiguous chest or limb leads
What is indicated by an elongated Q wave?
Cardiac tissue death (necrosis)
What may lead you to expect a posterior MI?
Prominent R wave in V1
ST depression in V2 and V3
Besides troponin, what labs may point to an MI?
C Reactive Protein elevation
WBC elevation
Brain Natriurietic Peptide (BNP) elevation
What is a concerning history for MI?
Chest pain, worse than regular angina
heavy/pressure/crushing
retrosternal, left, across the chest, radiating into neck, jaw, left UE, epigastrium, or between sholder blades
assx. n/v, diaphoresis, SOB
20% are silent, esp. in diabetics and elderly women
atypical sx in women and diabetics as well
Stable angina, which is chest pain that has been worked up and is not causing ishcemia can progress to unastable angina which is what?
When coronary artery flow is occluded, what happens?
besides atherosclerosis, what else can cause MI?
a partial arterial occlusion or NSTEMI
STEMI
vasospasm, vasculitis, dissection, genetics
What is the progression of CAD?
Normal heart
stable angina with some plaque build up
unstable angina when plaque cap ruptures
NSTEMI when blood clot forms, blocking artery
STEMI when heart tissue dies
What are the zones of infarction and what EKG changes are associated?
ischemia-def. blood supply with impaired repol. causes T wave changes
Injury-def. blood supply with inability to fully polarize causing ST segment shifts
Infarction-dead tissue, unable to depol. causes changes in Q waves
What specific T wave changes do you see with myocardial ischemia?
inverted T waves
tall, peaked T waves
depressed ST segment
What specific EKG changes do you see in myocardial injury?
ST elevation (heart tissue is dying)
What specific EKG changes do you see in myocardial infarction or necrosis?
Q waves will be bigger, indicating old infarct/dead tissue
What is the timeline of Troponin after an MI?
Immediately after, may not see any serum changes
1-4 hours after onset levels are detectable
10-24 hours after they peak
persist for 5-14 days
note that renal failure can cause false positives
How do you diagnose an NSTEMI?
NO ST elevation
elevated toponin, CK, and CK/MB
may have ST depression or T wave inversion, usually in contiguous leads
What finding may obscure ST elevations/segments?
New LBBB
Which leads correlate with which heart area/artery?
LAD
RCA
Circumflex
Posterior Descending A.
anterior wall infarct, leads V3, 4
inferior wall/RV infarct, leads 2, 3, avF
lateral wall, leads 1, avL, V5, V6
posterior wall infarct, V1-4
Bonus: Septal-V1-2
