ACS/MI/Angina Flashcards
Ischemia def
lack of O2 or blood flow
Infarction def
death of tissue, results from prolonged ischemia
Myocardial infarction
Heart attack
- cardiac myocyte death secondary to ischemia
Angina
- chest pain due to ischemia
- usually result of atherosclerosis / coronary artery disease
Coronary Artery Disease (CAD)
-predominant cause
atherosclerotic plaque formation and subsequent rupture
Two types of thrombi
- white: platelets and plaques
- red: platelets, fibrin, RBC
Occlusion type
- unstable angina
- NSTEMI
- STEMI
- Unstable angina: partial, white thrombus
- NSTEMI: partial of large artery or total occlusion of small vessel
- STEMI: total occlusion, red thrombus
Two general types of risk factor for CAD
modifiable
non-modifiable
Modifiable risk factors for CAD
- diet
- exercise
- smoking
- ETOH
- dyslipidemia
Non-modifiable risk factors for CAD
- age (men> 45 women>55)
- gender
- family hx
- personality type (??? like type A?)
suspected ACS labs
- general term
- 4 examples
cardiac biomarkers
- Troponin
- CK
- CKMB
- Myoglobin
*not actually enzymes but often called cardiac enzymes
What are cardiac biomarkers
cardiac injury = cellular disruption, loss of intracellular components which are called biomarkers
What is the basis for dx of ACS in the ER
cardiac biomarkers
Troponin
- important regulatory component in cardiac muscle
- most specific and sensitive biomarker for cardiac tissue
- if test is negative and within correct timing, very likely pt does not have disease (specific)
- if test is positive, pt very likely to have dz (sensitive)
Two types of troponin tested and what is difference
- Troponin T
- Troponin I
- typically only affect reference ranges
Sensitive troponin tests
higher threshold than ultra-sensitive tests for detection and time to detection
Ultrasensitive troponin tests
lower threshold for detection and early time to detection
Troponin
- time to rise
- time to peak
- time to norm
- 3-6 hours
- 12 hours
- 10 days
What should you monitor if mildly positive troponin
the change over time, 90-120 minutes in ER
if have sx suggestive of ACS for not long but no troponin yet does negative troponin mean no ACS?
NO - just might not be detectable yet
Why is troponin not a great option to monitor for re-infarctions
bc stays elevated for days
CK
Creatinine phosphokinase
- skeletal muscle, heart, brain
- lacks specificity due to multiple locations
- multiple reasons for elevation
- scott calls it a worthless test
CK timing
- time to rise: 3-4 hrs
- time to peak: 12 hours
- time to normalization: 3-4 days
*almost the same as CKMB
CKMB
- isoenzyme of CK
- more specific to myocardium
- multiple reasons for elevation
- scott calls it a worthless test
CKMB timing
Time to rise: 3-4 hrs
Time to peak: 12-24 hrs
Time to normalization: 3-4 days
*almost the same as CK
Myoglobin
- heme protein rapidly released from damaged m tissue
- non-specific to heart
- not used anymore in ER
- might be more useful monitoring post MI patients bc of faster time to normalization
Myoglobin timing
- Time to rise: 2-4 hours
- Time to peak: 12-24 hrs
- Time to normalization: 24-36 hrs
what is the gold standard in evaluation of chest pain
- EKG
* always get EKG and CXR for pt with chest pain in ED
Standard of care timing EKG for pt with chest pain
within 10 minutes of arrival to ER
Definition of ST elevation/depression
> 1 mm above or below isoelectric line
what is T wave inversion a characteristic sign of
myocardial ischemia
Where is isolated T wave inversion a normal variant?
Flipped T in 3 is Free
What is a new onset of LBBB synonymous with?
acute MI until proven otherwise (would want to compare with old EKGs if possible)