Cardiac Pathology Part 1 - Dr. Hillard Flashcards
leading cause of death in US
Coronary Artery Disease
Ischemic Heart Disease (Coronary Artery Disease)
Age, male, HTN, hyperlipidemia, DM, smoking
CAD most common cause
atherosclerosis
coronary artery emboli, vasculitis, and vessel spasms can also cause it
4 most common sites of coronary artery disease
- LAD (left anterior descending) = the widow maker
- Right coronary artery
- Left circumflex
- Left coronary artery
how to determine the dominance of a heart
the blood supply to the posterior descending artery (most are Right dominance)
left dominated heart what artery supplies the posterior descending artery
Circumflex artery
when id knowing dominance of heart important
- probable site of occlusion in MI
- planning coronary artery bypass grafting
- in irregular beats or skipping beats = AV block (AV node is supplied by PDA)
MI Sx seen
- crushing stabbing CP radiating to neck, jaw, arm
- SOB : congestion pulmonary
- sweating, N/V (usually posterior/ inferior infarct)
- 0.25 no sx (usually DM neuropathy)
serum marker for MI
Troponin*
CK-MB(creatine kinase-MB)
myoglobin
= regulate Ca mediated contraction of myocardiocytes
irreversible cell injury time
20min- 40min = necrosis
microvascular injury happens over 1hr
MI time for loss of function of heart from ATP depletion
1-2min
time for neurologic unlikely recovery
5min-7min, if 10min severe irreversible damage
during surgery cooling the heart helps prevent cell death as fast
CK-MB
CK-MM
CM-BB
- MB = cardiac muscle cells
- MM = muscles
- BB = brain and lung
first biomarker that peaks first
myoglobin
CKMB, cTnT and cTnl time to elevate, peak at what time, normalize when
- 3hr-12hr**
- 24hr
- CK-MB = 48hr-72hr*
cTnl, cTnT = >5days
LAD occlusion is what part of the heart
APEX, Anterior left ventricle and anterior 2/3 septum
Left circumflex occlusion what part of heart
Lateral LEFT VENTRICLE
Right Coronary Artery occlusion what part of the heart
right ventricle and left ventricle posterior heart
- posterior 1/3 septum
left dominant heart with circumflex artery occlusion where in the heart
the left ventricle lateral, and posterior
2 things that can cause subendocardial infarct
- reperfusion of transmural infarct (restoring BF fast, a thrombus is dislodged) regional
- global hypotension (shock, coronary stenosis)
multifocal microinfarction
many small infarcts within smaller intramural vessels
= seen in emboilic disease or drugs like cocaine
how does MI infarction spread
from inside =heart to outside (except the thin internal zone that gets perfused by blood passively)
what do you see in histology from 0min-30min
myofibrils relaxed, glycogen loss, M swelling
what do you see in histology from 30min - 4hr
- slight waviness of fibers at the border (from sarcolemma disruption)
what do you see in histology from 4hr - 12hr
- very early coagulation necrosis and edema
what do you see in histology from 12hr - 24hr
- increased coagulation necroisis and very developed at 24hr
- shrink Nuclei (pyknotic)
- darkly mottled heart (contraction band necrosis)
- myocytes hypereosinophilic
what do you see in histology from 1day-3days
- a lot of N
- nuclei loss = yellow tan infarct with surrounding mottling
what do you see in histology from 3days - 1 week
- M to phagocytose dead myofibers
what do you see in histology from 1 week - 1.5 weeks
- granulation
- collagen deposition (closer to 2 weeks)
what do you see in histology from 2weeks
scar tissue
what do you see in histology from after 2 months
scarring is complete and dense scar
when is it easy to see if an MI has happened on gross anatomy and also how to see it
- after 12hrs
- stain with lactate dehydrogenase stain (triphenyltetrazolium chloride) = this lactate leaks out from dead myocytes and staining turns everything red except scar and necrosis
reperfusion injury
when there is irreversible damage to myocytes :
- cell membrane disrupted with reperfusion causing influx a Ca = contraction
- contraction band necrosis
- hemorrhagic looking infarct
moltting
uneven patches of color
seen after 1 day
1day to 3days gross anatomy look
- yellow infarct, necrosis hyperemic border
- many N
- coagulative necrosis = loss of nuclei
after 2 weeks heart gross anatomy
-collagen increases more and more
-fibroblasts
scar is maturing and fully mature at 2mos
- loss of myocytes, inflammation, granulation
complications of an MI : early (within 24hrs)
- arrhythmias fatal
2. contractile dysfunction from cardio muscle death(can lead to cardiogenic shock)
complications of an MI : intermediate (2-4 days to 2 weeks)
- rupture of free wall, septum, or papillary muscles
- acute pericarditis (inflammation of pericardium) from inflammation N—-> M
- acute fibrinous pericarditis + serofibrinous pericarditis
acute fibrinous pericarditis
from inflammation a layer of fibrin develops over pericardial surface
serofibrinous pericarditis
fibrinous depbri and fluid collection in pericardium
complications of an MI : late (after 2 weeks)
- immune pericarditis = Dressler syndrome
- heart remodeling (fibosis) myocytes are separated in space :
= aneurysm formation
= arrhythmias fatal
= heart failure
most common cause of death from MI
fatal arrhythmia from within 1hr onset
= usually Vfib
2nd most common cause of death form MI
cardiogenic shock, also within 1hr to even 1day (from contractile dysfunciton = failure to pump) when cells die
intermediate effect of MI : rupture of wall
1. free wall rupture what happens
usually when wall weakens form necrosis and inflammation
1 .blood accumulation in pericardial space = prevents heart to open up and fill (DIASTOLE)
= ACUTE PERICARDIAL TAMPONADE —-> hemodynamic collapse
intermediate effect of MI : rupture of wall
2. septal rupture
- ventricular septal defect (usually in elderly with lower muscle mass), usually during anterior wall MI
intermediate effect of MI : rupture of wall
3. papillary muscle rupture
- valve incompetence and post infarct regurgitation
PE of pericarditis
pain with inspiration
pericardial friction rub heard on auscultation
main thing happening in intermediate MI complication
- myocardial rupture 2-4days post MI
2. AND acute fibrous or serofibrous pericarditis happening at the same time frame
Dressler syndrome what is it and SX (late so after 2 weeks past MI)
- fibrous pericarditis from immune reaction to myocardial proteins in the blood from previous MI = anti-heart AB causing inflammation to pericardium
- Fever, pleuritic pain, pericardial effusion
Ventricular aneurism + more arrhythmias (other late post 2 weeks MI) happen how
from remodeling and scarring (when conducting system is disrupted =arhythmias)
Ventricular aneurism + more arrhythmias (other late post 2 weeks MI) happen how
from remodeling and scarring (when conducting system is disrupted =arhythmias)
how to see aneurysm in ventricle
CT or angiogram
besides Dressler syndrome and ventricular aneurysm + arrhythmia , what is the last 2 types of late MI (post 2 weeks) complication that can happen
- Congestive heart Failure
2. Chronic Ischemic Heart Disease —-> CHF
Chronic Ischemic Heart Disease 3 causes
- healing infarct with fibrosis
- V remodeling
- hypertrophy
= fatal arrhymia
= failure heart , weakened
angina pectoris is what
recurrent CP from Myocardial Ischemia (not enough to cause MI)
= can happen with 70% stenosis of coronary A
angina pectoris is what
recurrent CP from Myocardial Ischemia = heart does not get enough O2 (not enough to cause MI)
= can happen with 70% stenosis of coronary A
pain from angina is caused by what
bradykinin and adenosine released from low O2
2 things that can cause a silent angina
DM neuropathy or previous MI
Stable angina
what
improves with
worsens with
stenotic occlusion of coronary A
- substernal P, sqeezing, burning
- Relieved by rest or vasodilators
- worse with physical activity, stress (not enough O2 for PE, only enough O2 at rest with the partial occlusion)
Prinzmetal Variant angina
what is it
improves with
worsens with
Episodic coronary A spasm
= relieved by vasodilators
= has no dependence on physical activity, BP, or HR
how to test for stable angina
exercise stress test, use EKG or echocardiogram and looks for changes during exercise
when does the Prinzmetal variant angina usually happens when, 3 complications that can occur, how often
at rest 1. coronary atherosclerotic disease 2. V arrhythmia 3. sudden death (3mo-6mo interval attacks)
vasodilator
nitrates
unstable angina
what is it, 2 causes of it
- Crescendoing pattern = increase severe and duration of pain
- rupture of plaque , partial non-occlusive thrombus (rest + exercise)**
- progressive mechanical obstruction (Exercise)**