MI

Question 1

What do STEMI and NSTMEI stand for?

Answer 1

STEMI- ST elevation myocardial infarction

NSTEMI- non ST-elevation myocardial infarction

Question 2

What occurs during AMI (acute myocardial infarction)?

Answer 2

AMI is going to be d/t a COMPLETE interruption of blood flow to all layers of the heart (epicardium–> endocardium), making it transmural.

Usually due to a thrombus.

Question 3

What is the pathobiology of how MI’s occur?

Answer 3

Most MI’s are d/t athersclerosis, a build up of lipoproteins and plaque formation.

The plaque will then break down and aggregate to form a thrombus, which is rich in platelets.

If coronary blood flow is completely occluded–> STEMI

If coronary blood flow is partially occluded–> UA or NSTEMI.

Question 4

Besides arthersclerosis, what are other causes of MI?

Answer 4

1. Vasospasm
2. Vasculitis
3. Dissection
4. Genetics

Question 5

What are the clinical manifestations of an MI

Answer 5

Chest pain

Pressure

Naseau

Sweating,

SOB

-Not manifested at one specific place-

Question 6

Can MI patients be tx with Nitro or rest, like those with angina?

Answer 6

No, they do not respond.

Question 7

20% of AMIs are painless. Who is more at risk for these?

Answer 7

Diabetic elderly women

Question 8

What part of an ECG do we see

1. Ischemia

2. Injury

3. Necrosis

Answer 8

Ischemia–> T wave ( will be inverted, tall and peaked)

Injury–> ST segment

Necrosis –> Q wave

Question 9

How do we recognize a STEMI on a ECG?

Answer 9

Men- ST elevation of 2mm or more at the J point in V2-V3

Women- ST elevation of 1.5mm or more in women in absence of LVH

or 1mm or more in 2 or more chest or limb leads

Question 10

How do we identigy a NSTEMI?

Answer 10

-Elevated cardiac enzymes

• ST segment is depressed
• T wave is inverted
• Chest pain

Question 11

How can we identify NSTE-ACS?

(Non ST elevation acute coronary syndrome)

Answer 11

- Cardiac enzymes are normal

• ST segment depression
• Inverted T-wave
• Chest pain

Question 12

When look at MIs, what part of the ECG do we look at?

Answer 12

QT duration; will tell us about myocardial infarcation (Q wave), myocardial ischemia (T wave) and myocardial injury (ST elevation).

Question 13

What are the zones of infarction

Answer 13

1. Q wave will tell us if there is a presence of dead tissue, which cannot depolarize.
2. ST shifts will tell us if there is any injury, which is caused by deficient blood supply and an inability to fully depolarize.
3. T wave tells us if there is any ischemia, which is caused by a deficient blood supply making repolarization impaired.

Question 14

Myocardial infarction to the LAD indicates infarction to what area of the heart?

This can be seen on what leads?

Answer 14

Anterior wall, which can be seen on leads V1-V6

Question 15

Myocardial infarction to the RCA indicates infarction to what area of the heart?

This can be seen on what leads?

Answer 15

Inferior wall, which can be seen on leads

II, III, AVF, V3R and V6R

Question 16

Myocardial infarction to the circumflex artery indicates infarction to what area of the heart?

This can be seen on what leads?

Answer 16

Lateral wall, which can be seen on leads

I, aVL, V5 and V6

Question 17

Myocardial infarction to the posterior descending artery indicates infarction to what area of the heart?

This can be seen on what leads?

Answer 17

Posterior wall, which can be seen on leads

V1, V2 and V3

Question 18

Ischemia causes _______ of the T wave due to _______.

What will the recipricol effect be on the opposite side of the infarct?

Answer 18

Ischemia will cause an inverted T-wave, due to altered repolarization.

On the opposite side of the heart, the T wave will be upright.

Question 19

Injury of the muscle causes ________ due to what?

What will the recipricol part of the heart look like?

Answer 19

Injury to the muscle will cause an elevated ST segment.

The recipricol part of the heart will have a depressed ST segment

Question 20

Infarction of the muscle causes _______, due to what?

What will the recipricol part of the heart look like?

Answer 20

Infarction of the muscle causes a deep Q wave because the tissue is not depoalrization.

Recipricol part of the heart will see a big R wave.

Question 21

SUMMARY: Infarction, injury and ischemia patterns. What will we see

Answer 21

Infarction- deep Q wave

Injury- ST elevation

Ischemia- Inverted T wave

Question 22

What do we see during recovery from subacute and chronic stages of an MI?

Answer 22

1. ST goes back to nomral.

—then—

2. T wave goes back to normal

Question 23

What is a subendocardial infarction?

Answer 23

Subendocardial muscle is ischemic and injured, but not dead.

Thus, you will see ST elevation or depression.

Question 24

In the lab, for an MI, you will see

____ WBC

_____ CRP

_____ BNP

Answer 24

increase in all.

BNP–> increase in ventricular wall stress and fluid overload

Question 25

What are markers of necrosis?

Answer 25

High troponin 1 (cTnI) or T (cTnT) present 1-4 hours after AMI.

Peaks 10-24 hours.

Persists for 5-14 days.

Be careful that renal failure can cause false + cTnT

Question 26

What will a non-stemi look like?

Answer 26

ST segment is not above baseline.

If anything it is depressed