Ischemic Heart Disease: Part 2 (INC) Flashcards
What do all patients w/ chest pain get?
An EKG
Difference between low, intermediate, and high risk patient?
HEART score to see the risk of the patient and then work them up from there
0-3 = no testing
4-6 = admit for observation (stress test)
7-10 = admit with invasive strategy from cath lab immediately
Why do you use an EKG?
See if there are symptoms of ACS w/in 10 minutes of arrival!!! (time is tissue - dead meat don’t beat)
serially monitor - look for hyperacute T-waves and T wave inversions
let’s you know if there are electrolyte abnormalities as well
Who should routinely get EKG?
DM, female, and elderly
What is the first presentation of ACS (MI)
Peaked T waves
Look it is diffuse, which would be hyperK, or localized ACS
get a BMP
How many leads do you need to diagnose with ACS?
ST elevation in 2+ contiguous leads
should know if it is an
If you see ST segment elevation or new LBBB (tombstoning) what do you do?
You do NOT order labs - go straight to the cath lab
Evolution of an MI
min-hours: St elevation after minutes to hours
1-2 days: ST elevation
Pathological Q wave
Inverted T waves
Scar formation
What is the best cardiac enzyme to diagnose? What are the others?
TROPONIN - specific to cardiac tissue
also myoglobin and CK-MB, but not as specific to the heart
only ordered if no ST elevation (order if there is T wave inversions, hyperacute T-waves)
What is Troponin?
contractile protein that normally is not found in serum
It is only released when myocardial necrosis occurs
HIGHLY sensitive AND specific
Why would you order other labs for troponin?
Due to it’s trend
Increase within 3-6 hrs
Peak at 24-48 hrs
Return to baseline over 5-14 days
Measure troponin levels at presentation and then again 90 minutes
Then every 6-8 hrs after symptom onset x 3 or until trending down
If there is an elevation of troponin, do we know what they have?
NO
need differential - just tells you that there is damage to the heart
What can cause false elevation of troponin?
If there was surgical procedure
What is considered normal troponin and why is this important to know?
Normal = 0 - 0.04
used as a baseline, as there is variance in baseline between patients
Why is Creatine Kinase (CK-MB) use sometimes?
Less sensitive and specific
Increase 4-8 hrs after injury
Peak around 24 hrs
Return to normal by 48-72 hrs
Positive if CK-MB >5% of total CK
need to order a CK and MB and then multiply by 0.05. It is positive if greater than this
What are some false positives of Ck-MB and why?
Non-cardiac related events that affect muscles
trauma, muscle, disease, DM, PE
How fast is myoglobin released and why is it useful?
High sensitivity, poor specificity
May be detected as early as 2 hours after an AMI
It is the MOST sensitive
Only real use is in the very early detection of MI
What is LDH used for?
Not really useful for MI
could be elevated in acute MI
Why is some other tests better than troponin?
If there is new onset of chest pain, because troponin will remain elevated for up to 10 days
Which cardiac enzyme is most appropriate / diagnostic for:
Patient with chest pain for 90 minutes?
myoglobin
chest pain for 6 hours
Patient with chest pain for 6 hours?
Troponin
Patient with recurrent chest pain 36 hours after having PCI for an MI?
CK-MB best
or myoglobin (but may be falling down)
what might you see in CBC for ACS?
Leukocytosis
What might you see for CRP and ESR in ACS?
May remain elevated
ESR (may remain elevated for 3 days)