Lecture 4 - Cardiac Pathology & Pharmacology Flashcards
What creates the P wave?
Atrial contraction
What causes the QRS wave?
Ventricular contraction
NOTE: the atrium is still contracting at this point, however, its covered because ventricular contraction is so much more
KNOW: Myocardial perfusion = the fluid (blood) that your heart gets
When does myocardial perfusion happen?
Diastole - Happens during periods of relaxiation (when the ventricles arent actively contracting)
KNOW: The heart has many collateral vessels - just like the circle of willis - to keep blood from being blocked
What inhibits myocardial perfusion?
Resistance - such as atherosclerosis
Where does plaque buildup originate?
Tunica intima
What is coronary perfusion pressure?
* What happens if this is inadequate?
The pressure gradient that moves blood through the hearts coronary arteries to supply the myocardium w/ O2
If its not enough it could lead to ischemia which could lead to a MI
Cornary Perfusion Pressure equation
Cornary Perfusion Pressure = Aortic diastolic pressure - left ventricular end diastolic pressure
Cornary perfusion pressure. represents the net pressure driving blood into the coronary arteries to supply the heart muscle
Aortic Diastolic Pressure - BP in the aorta during diastolie - its the pressure available to push blood into the coronary arteries, which supply blood to the artery
LVEDV - pressure inside LV at the end of diastole - represent the back pressure or resistance that opposes the flow of blood into the coronary arteries
The higher the aortic diastolic pressure, the more force there is to push blood into the coronary arteries
However, the LVEDV acts as a resistance opposing force. If LVEDP is high, it reduces the effective pressure available for cornary blood flow
If CPP is too low, the heart may not get enough blood, leading to conditions like ischemia which lead to MI
What is the occulsive force in endocardium?
Left ventricular end diastolic volume - because it can push on the endocardium (exert pressure) blocking the blood flow to it
Coronary perfusion pressure = aortic driving pressure
2 biomarkers for acute coronary syndrome and heart failure?
1) Troponins
2) Natriuretic Peptides
TEST Troponins have a high specificity for myocardial cell injury or infarct (they exist when these things are going on).
What is the norm for cardiac Troponin T?
What is the norm for cardiac Troponin I?
What is the norm for High-Sensitivity Cardiac Troponin (Men and Women)?
Troponin T = <0.1 ng/L (over this # is abnormal)
Troponin I: <0.03 ng/mL (over this number is abnormal)
High-Sensitivity Cardiac Troponin: Women < 14 ng/L; Men <22 ng/L (greater than these #’s is abnormal)
Troponin #’s have to be trending down for PT to see them. Describe the trend
3 consecutive labs trending down
They can still be elevated, they just need to b going down
Why might we not want to do exercise w/ someone w/ heart pathology?
Because at rest all the blood is routed to vital organs; however, w/ EX, some of that blood is routed to external musculature, not leaving as much blood for internal viscera, meaning they won’t have as much blood to work with, and if they’re already ischemic this could be problematic.
KNOW: Natriuretic Peptides are made by the heart, and commonly used to assess for heart failure.
Brain Natriuretic Peptide (BNP) is releated in response to what two things?
Artiral or Ventricular Stretch
A Brain Natriuretic Peptide (BNP) count of what indicates heart failure? Which number is a normal #?
* What causes an increase in this?
> 400 indictes that heart failure is likely
<100 is normal
NOTE: This # increases over the lifetime because it responds to increase stretch in the heart, and we have cardiac enlargement as we age
Which sex has more Brain natriuretic peptide?
Female
Does Obesity cause more or less brain natriuretic peptide and why is that an issue?
Causes Lower BNP
It’s an issue because we might not know they’re at risk for heart failure
* I think the reasoning is due to increased blood volume in obese people
N-terminal fragment of pro-brain natruiretic peptide (NT-pro-BNP) is another fariation of natriuretic Peptides. What number is normal?
<300 pg/mL
TEST A value off 200 is normal for Brain natruitetic Peptide (BNP) or N-terminal frament of pro-brain natriuretic peptide (NT-pro-NBP)?
NT-pro-NBP
Anything under 100pg/mL is normal for BNP
Anything under 300 pg/mL is normal for NT-pro-NBP
Symptoms that signify an acute MI, as a result of insufficient supply to cardiac muscle =
Acute Coronary Syndrome
What causes a type 1 myocardial infarction?
What causes a type 2 myocardial infarction?
* What sex does this happen more in?
A blockage = type 1
Mismatch of supply and deman ratio = type 2
* can also be due to spasm
* Women > men
KNOW: Diagnosis of mycardiac infacrtion made by a rise/fall/both in a blood test sensitive to myocardial damage with at least one value above the 99th percentile of the upper reference limit with cinical evidence
* labs and clinical symptoms
* mainly looking at the 3 troponin levels
A patient has a full thickness myocardial infarction. What does this mean and what structure gets affected thats really important?
Full thickness means that cell death happens all the way down to the endocardium
Its super bad because the cardiac valves originate from the endocardium, meaning there can now be backflow/valve pathologies.
STEMI/NSTEMI are cnosidered type 1 or type 2 maycardial infarctions?
They’re both considered type 1
caused by some kind of blockage
3 things that make up NSTEMI
1) No ST elevation
2) Less Necrosis
3) Elevation of cardiac biomarkers (think tropinin)
Remember, this is classified as a type 1 myocardial infarction.
NOTE: Stands for No ST elevation Myocardial infarction
What 3 things make up a STEMI myocardial infarction?
1) ST elevations in lateral leads (V5-6)
2) Most severe
3) Abnormal cardiac markers
NOTE: Stands for ST elevation myocardial infarction
Classified as a type 1 myocardial infarction (some kind of blockage caused it)
Whats more severe STEMI or NSTEMI?
STEMI
Which one of these is a STEMI ECG?
2
Notice the ST segment elevation
NOTE: The isoelectric line is in yellow
Which of these is classified as a NSTEMI ECG
3