Heart Pathology Flashcards
What is an acute myocardial infarction?
usually caused by sudden thrombotic occulusion of a coronary artery at the site of an atherosclerotic plaque that has become unstable due to a combination of ulceration, fissuring and rupture.
25% of acute MI’s are what?
CHF
Left ventricle infarcted
What is right ventricular ischemia or infarction?
occurs in up 1/2 of inferior wall of infarctions
thrombosis
blocks vessels due to aggregate of plaques
STEMI
ST-segment elevation MI
WHAT IS A STEMI?
complete occlusion of blood/oxyegn to large portion of mycardium, so no O2 getting to heart
Stemi is based upon
reperfusion capacity of myocardium, and is a more rapid ST segment resolution with treatment resulted in better prognosis/ survival rate
absence of st
indicates failed reperfusion treatment
Where do thrombus formation occur?
most often at the site of atheroscelerotic lesion, thus obstructing blood flow to myocardial tissues
Plaque rupture
thrombus formed on site and occlude blood, thus causing MI
Zone of Infarction
can’t reverse or save area
ischemia and reperfusion injury is accompanied by inflamatory response
Zone of hypoxic injury
reversible
immediately surrounding the zone of infarction is region
Zone of ischemia
reversible
if blood repercussion reestablished
6 Factors that impact size of infarction
extent severity duration of ischemic episode size of vessel amt of collateral circulation status of intrinsic fibrinolytic sys vascular tone metabolic demand of myocardium at the time of event
MI most damage is where
left ventricle leading to alteration in ventricular function, but can occur in right or both at same time
Where are MI located in left ventricle?
Anterior septal lateral posterior inferior walls of left ventrical
Transmural infarction
used to imply an infarction process that has resulted in necrosis of the tissue in al the layer of the myocardium
why transmural infarct?
Heart functions as squeezing pump, sys and diastolic efforts can be significantly changed when segment of heart muscle is necrotic and nonfunctional
What happens if transmural infarct is small, the necrotic wall may be . . . ?
dyskinetic- difficulty moving due to scar tissue
What happens if transmural infarct is more extensive?
The myocardial muscle may become akinetic meaning without motion
Saving hear after MI occurs ?
a substantial amt of myocardial tissue can be saved of flow is restored within 6 hrs after onset of coronary occlusion
cellular changes associated with MI include what 3 things?
- the development of infarct extension (new myocardial necrosis),
- infarct expansion (a disproportionate thinning and dilation of the infarct zone), or
- Ventricular remodeling (a disproportionate thinning and dilation of the ventricle).
reperfusion injury
supplemental oxygen support in individuals with STEMI
Ischemia Reperfusion injury is when?
cardiac myocyes more glycolytic resulting in pH shift (decreased pH/ increased acidity)
Ions associated with ischemia ?
Increase in Na+ inactivation of Na/K pump based upon pH, the Na/K pump allows rest, and this stops working and is not getting rid of sodium anymore
What does increased Na+ cause?
depolarized state with Ca2+, which is repelled everywhere and results hypercontracture of ischemic zone resulting in altered environment in cell. The cell/zone = dead can’t save
hypercontracture defin
constant depolarized state of myocyte
Upon reperfusion injury what happens
ionic injury dissipates through gap junctions (cardiac cells autorhymatcity/ juxtacrine). pH shift results in lysosomal damage and an increase in free radicals
change pH upon reperfusion results in
autolysis cell die
Major cardiac arrhythmias
referfusion injury
Clincial manifesstions of MI (male)
Sudden sensation of pressure (crushing chest pain)
Radiation to: Arm, Throat, Jaw, Neck, and mid thoracic back pain.
Constant pain lasting 30 minutes to an hour
SOB
Pallor
Profuse perspiration
Female clinical manifestitations of MI
Major symptoms: SOB (middle of night), and chronic unexplained fatigue
