Ischemia/Infarction Flashcards
What is main cause of occlusion?
Thrombosis
What is main cause of coronary artery spasm?
Smooth muscle constriction
If patient complains of substernal chest pain with radiation of pain to jaw or left arm, nausea, diaphoresis, and shortness of breath, suspect:
MI
Who is prone to silent MI?
women, diabetics
What enzyme is particularly affected in event of MI?
Troponin I
Effect of MI on troponin I levels
Rise early and stay elevated for days
CK-MB during MI:
6 hours to rise and then normalize in 48 hours
First change to EKG during MI:
Peak T-wave, then inversion
ST segment elevation/depression: which is more common with MI?
Elevation
Why are new Q waves diagnostic of MI?
They indicate irreversible myocardial cell death.
Change to EKG within minutes during MI:
Peaked T wave
Change to EKG within hours-minutes during MI:
Progression of ST segment elevation
Change to EKG within hours-days during MI:
Loss of R wave, Q wave formation
If ischemia is reversed, what happens to the EKG?
T-wave will return to normal.
What is the only diagnostic EKG criteria in event of MI?
New Q-waves
Is ST segment elevation repairable?
Yes
What is J point elevation?
A type of ST segment elevation seen in normal hearts
What is a J point?
Where the ST segment takes off from the QRS complex
Appearance of new Q waves in EKG indicates:
Irreversible myocardial death
At time of Q wave appearance, what happens to ST segment?
ST segment returns to normal
In leads more distant from site of infarction, what will you see?
Tall R waves
ST segment depression when ST segment and T wave changes are present
What does the region of the heart muscle that suffers from infarction depend on?
Which coronary artery becomes occluded and extent of collateral blood flow
What is the pathway of the RCA?
Runs between the right atrium + right ventricle, swings to posterior surface of the heart
LCA divides into?
LAD artery and left circumflex artery
