Myo Ischemia and Infarct Intro Flashcards
Myo O2 supply:
O2 delevered thru?
Returned thru?
Coronary arteries deliver O2 blood to myo cells
Coronary veins return deO2 blood to RA via coronary sinus
Myo Ischemia is?
Inadequate blood supply of O2
Reversible
No permanent damage
Ischemia affects what region first?
Why?
sub-endo
farthest from supply and has greatest wall tension
Ischemia caused by?
Atherosclerosis Vasospasm Thrombosis/embolism ↓ vent fill time (tachy) ↓ coronary artery fill pressure (hypoTN, aortic valave dz)
Myo Infarct is?
death of myo cells
replaced w/ scar tissue
Breakdown products of cell death are? (3)
troponin
CK-MB
myoglobin
Myo injury is?
cell damage beyond ishemia
w/o tissue necrosis
Ischemia appears as what on ECG?
Inverted T waves (delayed repol)
Tall/peaked T waves
Depressed ST seg
Transmural Ischemia is?
ischemia of full myo wall,
repol takes longer,
repol can reverse from endo to epi
Transmural Ischemia appears as what on ECG?
Symmetrical/inverted T waves, V2-4
Peaked T waves (hyperacute) defined as?
> 6mm tall in limb leads
12mm tall in precord leads
OR
2/3 height of R wave
ST segment depression significant when?
> 1mm below baseline w/i 0.04 sec of J point
In more than one lead
Subendo Ischemia/Injury/Infarct is?
involvment of inner heart w/o extending thru whole vent wall
Subendo Infarct/Injury appears as what on ECG?
Flat ST seg w/ slight T inversion
ST segment elevation significant when?
> 1mm above baseline, 0.04 sec to R of J point
In more than one lead looking at same part of heart