Clinical Myocardial Infarction Flashcards
What classically precipitates angina?
exercise, stress, or cold.
What is stable angina?
angina that occurs with exertion or after a big meal. This generally means that a plaque has become large enough to produce a partial obstruction of a coronary artery. IT occurs at a relatively fixed and predictable point and can slowly change over time (ex. same thing happens every time they walk the dog).
Ischemia occurs when activity causes an increase in O2 demands to the point that is beyond the coronary blood supply.
What is acute coronary syndrome (ACS)?
A term used to describe pts with acute chest pain and other symptoms of myocardial ischemia (condition brought on by a sudden reduction or blockage of blood flow to the heart). It could be 3 things:
- unstable angina
- non ST segment elevation MI
- ST segment elevation MI
What causes acute coronary syndrome (ACS)?
a reduction in myocardial blood flow due to disruption of atherosclerotic plaque caps leading to platelet aggregation, or thrombus formation at site of an atherosclerotic plaque.
What is a STEMI?
ST segment elevation
What is a non-STEMI?
ST segment depression (similar to unstable angina) only this will show cardiac enzymes and unstable angina will not.
What are the clinical features of IHD?
chest pain. People define “pain” differently. So be sure to ask if they have tightness, heaviness, pressure…
What questions should you ask?
You need to ask about its severity, location, radiation, duration, and quality. Also diaphoresis, dyspnea, and syncope.
How many patients with AMI are clinically unrecognized?
30% Some have had atypical symptoms for which they didn’t pursue medical advice.
Who are most at risk to have clinically unrecognized symptoms?
women and elderly often because they have atypical symptoms such as GI symptoms.
What are the cardiac risk factors?
age over 40, male, post-menopausal women, family history with 1st degree relative, smoking, hypertension, DM
How helpful is the physical exam in the setting of ACS (aka MI)?
not very helpful actually. Instead you have to look at the person because they will look like crap.
What heart sounds are related to ACS (aka MI)?
- S1 and S2 are often diminished due to poor myocardial contractility.
- S3 can be present due to failing myocardium
- S4 is common in pts with long standing HTN or myocardial dysfunction.
- New systolic murmur is an ominous sign! This signifies papillary muscle dysfunction, flail leaflet of mitral valve or VSD.
What are the 5 types of MI?
he said we are only going to talk about types 1 and 2
- Type 1= typical plaque rupture.
- *Type 2= SUPPLY DEMAND MISMATCH: MI secondary to ischemia due to either increased O2 demand or decreased supply, coronary embolism, ANEMIA, arrhythmias, hypertension or hypotension.
- Type 3= sudden unexpected cardiac death
- Type 4a= MI associated with PCI. Type 4b= MI associated with stent thrombosis
- Type 5
What is the duration of symptoms for angina?
typically less than 20 mins if stable.
Are the symptoms similar between unstable angina and MIs (NSTEMI or STEMI)?
YES
Are the serum biomarkers (troponins) the same or different between unstable angina and MIs (NSTEMI or STEMI)?
different. Unstable angina will not show serum biomarkers but both NSTEMI and STEMI will show serum biomarkers.
How do unstable angina and NSTEMI compare on the EKG?
they are the same! Both show ST segment depressions with T wave inversion.
So what really is the difference between a type 1 and type 2 MI?
type 1 involves a rupture with thrombus, whereas type 2 means you can go about your normal activities, but you have fixed atherosclerosis and supply-demand imbalance, so when something changes you can’t get enough blood to the myocardium and can spill some enzymes.
What is the best way to determine an MI?
12 lead EKG (must be read within 10 mins of a pt complaining of chest pain in the hospital).
However, even though it is the best, it still has a low sensitivity of picking up an acute MI.
If a patient comes in complaining of chest pain and has a new LBBB, what does this mean?
they are having an MI until proven otherwise!
**What leads on the EKG correspond to specific coronary arteries?
- leads II, III, aVF= RCA or LCX
- leads I, aVL= LCX or diagonal branch of LAD
- V1-4= LAD
- V5-6= LCX or LAD
If you have ST depressions, can you figure out what coronary artery we are dealing with?
NO!! Only with ST elevations can we distinguish between coronaries.
**What will you see on an EKG with an anterior MI?
STEMI V1-4
**What will you see on an EKG with an inferior wall MI?
- ST segment elevation in II, III, and AVF
- ST segment depression in I, AVL, or both (reciprocal changes)
- Inferior wall is supplied by RCA and LCX
**What will a lateral wall MI look like on an EKG?
- ST elevation in I, AVL, V5-6
- high lateral wall (I and AVL)
- low lateral wall (V5-6)
**What will a posterior wall MI look like on an EKG?
This one is different
- ST DEPRESSION (V1-4)
- duration of R wave to S wave >1 (V1 or 2)
- can even place leads around the back (V7-9) and see ST elevations in these.
What 3 differentials should go through your head when you see anterior ST depressions in leads V7-9?
- reciprocal changes
- concomitant anterior ischemia
- posterior infarction
What will you see in a right ventricular MI?
RCA occlusions.
You will see ST elevations in V4 RIGHT when using RIGHT SIDED LEADS.
- Look also for Q waves in leads II, III, and aVF.