L4 - MI Flashcards
STEMI is caused by what?
Occlusion
Somebody with STEMI needs what most?
Surgery to open occlusion
What does STEMI look like on ECG?
Low R wave
High ST
Inverted T wave
What is the diagnosis if see ST elevation?
If in anterior leads = anterior infarction
If in inferior leads = inferior infarction
What are the anterior leads?
1
AVL
V1-V6
(AVR not in either classification cuz right on the border)
What artery supplies the areas of the anterior leads?
LAD
What are the inferior leads?
2
3
AVF
(AVR not in either classification cuz right on the border)
What artery supplies the areas of the inferior leads?
Supplied by right coronary artery
Is inferior or anterior infarction worse?
Anterior/LAD is worse
Describe the evolution of the coronary thrombi?
Thin cap over lipid core only occludes vessel about 40%. No problem
Something causes corner of cap to rupture & spill lipid –> platelets aggreagate to prevent spillage of lipid = Mural thrombosis with some stenosis
RBCs aggregate with platelets to form thrombis –> occlusion –> 0 or near 0 flow
What layers of muscle are effected first during infarction & why?
Subendocardial
farthest from blood supply
How do the different layers of muscle get injured vs. time?
@ 30 min = subendocardial necrosis
4 hours = subepicardium necrosis
6-12 hours = entire wall
What is the catch phrase which stresses quick action for MI?
Time is muscle
What is the term for time from patient arrival to start of catheterization? Target?
Door to balloon time
2 hours
What is it called when the cath lab, the cath technicians and cardiologists are all told of MI patients arrival & need for surgery?
STEMI alert
What cardiac markers are currently used for MIs? When do they first raise above normal?
Troponin & CK-MB
4 hour after injury
What is the most sensitive cardiac marker?
Troponin
Patient has had chest pain for 3 hours but normal troponin. Diagnosis?
Still could be MI, too early for troponin to be raised
With relation to MI, crackles in the lungs is a sign of what?
Pulmonary edema
How is ejection fraction measured?
Echo
Chronic MI treatment/prevention?
Control risk factors
Lowering lipids…
Acute MI management?
Nitrates
Beta blocker
ACEI for LV dysfunction
Aspirin or Clopidigrel/Plavix (anti-platelet aggregation)
Heparin (anti-coagulant)
If not near a hospital & angiography is not available, how do you open an occlusion?
Thrombolytic agents
Who should not receive nitrates during acute Mi management?
Somebody with a BP that is already low
What is the best way to administer nitrates? Why?
IV
Can shut it off if BP gets too low. Transdermal & sublingual stay in system for hours
Who should not receive beta blockers during the management of acute MI?
Low BP or HR
Who should receive beta blockers during the management of acute MI?
Atrial fib with high HR
What is the relationship of death & echo ejection fraction? “Tipping point”?
As ejection fraction increases, deaths decrease
If have 40% ejection fraction, have a decent shot at being ok
What is normally occurring during ST segment? Why is ST segment elevated in MI?
Ventricle should already be depolarized & atria have already returned to normal = flat line
During injury of the heart, some cells are depolarizing or repolarizing when they shouldn’t be
