Myocardial Infarction

Question 1

In an MI, what breaks off a coronary artery? What happens next to cause the MI?

Answer 1

An atherosclerotic plaque breaks off, a clot forms which blocks the coronary artery. The heart muscle dies when it does not get enough oxygen.

Question 2

What are 4 etiologies of MI

Answer 2

(1) Atherosclerosis
(2) Prolonged vasospasm / a-fib
(3) Cocaine
(4) Hypotension

Question 3

What are 4 risk factors for getting a MI?

Answer 3

(1) Smoking
(2) Hypertension
(3) Hyperlipidemia
(4) Diabetes (a risk factor for atherosclerosis)

Question 4

What are 4 lab tests for detecting MI?

Answer 4

(1) Troponin I
(2) Troponin T
(3) CK-MB
(4) Myoglobin (though not cardiospecific)
* Labs may be normally initially! Serial

Question 5

Which lab test is most useful for evaluating reinfacrtion?

Answer 5

CK-MB

Question 6

The cardiac specific physical exam for MI:

Answer 6

Could be within normal limits, or abnormal.

• JVD
• Kussmaul sign
• Soft heart sounds
• Atrial gallop (S4)

Question 7

Name the two types of MIs

Answer 7

(1) N STEMI and (2) STEMI

Question 8

N-STEMI: Describe the blockage in the artery and describe 2 ECG findings.

Answer 8

Subendocardial (inner third of the artery). Doesn’t show ST elevation. ECG shows

(1) ST depression
(2) T-wave abnormality.

Question 9

STEMI: Describe the blockage in the artery. What are 4 things you can see on the ECG?

Answer 9

Transmural (whole wall of artery thickness).

(1) ST segment elevation
(2) Negative Q waves
(3) Loss of R wave
(4) L BBB

Question 10

Symptoms of MI

(1) Where is the pain located? Does it move?
(2) GI system?
(3) Overall energy?
(4) MI could also be…

Answer 10

(1) Chest pain that radiates
(2) Nausea
(3) Fatigue
(4) *Silent (diabetic patient or older adult)

Question 11

Imaging done for MI

Answer 11

CXR to r/o aortic dissection

Question 12

Fibrinolytic therapy is done

Answer 12

Within 30 minutes

Question 13

Medications for a confirmed MI

(1) Antiplatelets (two)
(2) Decrease the BP and cardiac workload
(3) Slow HR and contractility
(4) Lower cholesterol
(5) Anticoagulant

Answer 13

(1) Aspirin or Clopidogrel if Aspirin allergy
(2) ACE inhibitor - Decrease BP and cardiac workload
(3) Beta blocker - Bisoprolol - Slow HR and contractility
(4) Statin - Lower cholesterol
(5) Also warfarin/fondaparinux (anticoagulants)

Question 14

Signs of an MI

(1) The HR could be
(2) With an inferior infarction the HR is
(3) In shock, the patient will have ___BP
(4) BP could be ____
(5) Describe the skin
(6) If the patient has heart failure, you could hear this upon auscultation of the lungs

Answer 14

(1) Tachycardiac
(2) Bradycardiac
(3) Low
(4) High
(5) Cool, clammy
(6) Inspiratory crackles

Question 15

Name 5 complications of a MI

(1) Most common cause of death
(2) - (5) related to the heart

Answer 15

(1) Arrhythmia
(2) CHF
(3) Myocardial rupture
(4) Cardiogenic shock
(5) 2nd MI (10% of cases)

Question 16

There are many things that can be a differential diagnosis of MI. 
S
A
M
P
P
P
C

Answer 16

Stable Angina 
Aortic Dissection 
Myocarditis
Pericarditis
Pneumothorax 
Pancreatitis 
Cardiomyopathy

Question 17

The (1) quality of chest pain differentiates pericarditis from MI / PE and (2) ECG changes. Describe (1) the quality of chest pain and (2) ECG changes.

Answer 17

(1) The quality of chest pain is sharp, doesn’t worsen with exertion, and feels better sitting up
(2) Diffuse ST-elevation or PR depression.
Bonus: Friction rub