ACS pt1 Flashcards
What is ACS?
An imbalance between myocardial O2 supply and demand
What makes ACS problems worse?
If the clot(s) occur higher up the arteries of the heart
What differentiates ACS?
The plaque’s fibrous cap ruptures, causing a blood clot
What is type 1 ACS?
Spontaneous MI: atherosclerotic plaque rupture
What is type 2 ACS?
- MI secondary to ischemic imbalance: O2 supply or demand mismatch to heart (ex. vasospasm, anemia, hypotension)
- Rupture hasn’t necessarily happened
What is common epidemiology of ACS?
- Median age is 68 yo
- Males are more likely at a 3:2 ratio
- For some, ACS (like heart attack) is first presentation of CAD
- Approx 70% of pts who experience ACS has a NSTEMI
What are the region and radiation of ACS?
- Retrosternal chest pain
- May radiate to shoulder, down left arm, to back, or jaw
- Most often at REST
What are the s/sx of ACS?
- Nausea, vomiting
- Diaphoresis
- SOB
What patient population are atypical ACS sx more likely in?
- Elderly
- Females
- Diabetics
- Pts w impaired renal function
- Dementia
What are these atypical (noncardiac) sx?
- Epigastric pain
- Indigestion
- Stabbing or pleuritic pain
- Increasing dyspnea in the absence of chest pain
What are high risk features of pts with chest pain?
- Continuing chest pain
- Severe dyspnea
- Syncope/presyncope
- Palpitations
What should be done w pts with chest pain and high risk features?
Transported by emergency medical services
What is the first thing done to all possible ACS pts who arrive at an emergency facility?
All pts w acute chest pain should have an ECG within 10 min of arrival
What does a normal P wave indicate?
The atriums contracting
What does a normal QRS wave indicate?
The ventricles contracting
What does a normal T wave indicate?
The ventricles relaxing
What is a common ECG finding with a STEMI?
ST elevation
What is a possible ECG finding with a STEMI other than a ST elevation?
Q wave change:
- Often not present in initial, develops over hours to days
- Electrical ‘hole’: scar tissue cannot conduct electricity
- May disappear after reperfusion once scarred tissue recovers
- Often remain permanently
What are possible ECG findings with a NSTEMI/UA?
- Normal ECG
- ST depression, transient ST elevation, or new T wave inversion are possible
What does not occur or unlikely to in a NSTEMI/UA ECG?
- Q wave changes unlikely
- No ST elevation
When should troponin be measured?
- Measured asap after presentation of acute chest pain and ACS once arrival to ED
What releases troponin?
Necrotic myocytes (injured heart cells) into bloodstream
What is the gold standard to determine myocardial injury?
Troponin
Which troponin is PREFERRED?
High sensitivity troponin
List the advantages of high sens troponin.
- Greater sensitivity and negative predictive values
- Shorter time from onset of chest pain to detectable conc
What is the measurement unit of high sens troponin?
ng/L
What is the other troponin that is not used as frequently?
Conventional troponin
What is the measurement unit of conventional troponin?
ng/mL
What is sensitivity?
Likelihood of detecting a disease when it exists (true positive rate)
What is specificity?
Likelihood of not detecting a disease when it does not exist (true negative rate)
What are normal values of troponin?
- High sens: <14 ng/L
- Conventional: <0.05 ng/mL
How often should troponin tests be done?
3 levels over 12 hours
Why must multiple troponin tests be done?
Initial may be negative
What is another biomarker to check for myocardial injury?
Creatinine kinase myocardial band (CK MB)
Why is CK MB test not done anymore?
- Less sensitive than troponin
- Substantially more tissue injury is required for its detection
What are the characteristics of stable angina?
- Chest pain occurs with exertion
- Predictable
- Relieved by rest
- Lasts a short time (<5 min)
What are the characteristics of unstable angina?
- Chest pain may occur at rest, while sleeping, or w little physical exertion
- More severe and lasts longer (may be >30 min)
What are differences between UA and NSTEMI?
UA:
- Less ischemia
- Does not lead to detectable quantities of troponin
NSTEMI:
- Troponin is elevated
What is a thrombolysis in myocardial infarcation (TIMI) risk score?
It is the risk of experiencing either death, MI, or urgent need for revascularization within 14 days
What is a low risk TIMI score?
0-2 points
What is a medium risk TIMI score?
3-4 points
What is a high risk TIMI score?
5-7 points
What % of pts have a low risk TIMI score?
5-8%
What % of pts have a medium risk TIMI score?
13-20%
What % of pts have a high risk TIMI score?
26-41%
What is ventricular remodeling?
Changes in size, shape, and function of left ventricle after an ACS
What factors are involved in ventricular remodeling?
- Activation of renin-angiotensin-aldosterone system
- Hemodynamic factors (increased preload and afterload)
What does ventricular remodeling lead to?
Leads to heart failure:
- Increased morbidity and mortality
What does MACE usually include?
Stroke, MI, CV death
