Ischemia

Question 1

What is important to know about the phases of ischemia to irreversible infarction (losing cells)

Answer 1

1. Hyperacute T waves
2. Infarction (inverted T waves)
3. ST segment elevation
4. Switch from an R wave to a Q wave (shows irreversible cell death)

Question 2

What is a T wave indicative of?

Answer 2

Ventricular repolarization

Question 3

What makes a hyperacute T wave for MI

Answer 3

ST segment blurs into the T wave

Broad Width of the T wave that goes up to a mountain top (rounded rather than pointed)

no strict rules, just has to be big essentially (typically at least 1/3 or 1/2 of the QRS complex)

different leads may be normal, and abnormal ones suggest the location of where the infarction may be (anterior leads for example)

Question 4

What is segment serves as a baseline for an EKG?

Answer 4

The PR segment

Question 5

After seeing hyperacute T waves, what do you see an MI progress to include?

Answer 5

Elevated ST segment

Question 6

What is an elevated ST segment?

Answer 6

ST segment is at least 2 boxes above the PR segment

Question 7

What type of ST segments tend to be a better prognosis?

Answer 7

If you could put two dots over it and it makes a happy face = good
sad face = bad

NOT ALWAYS THE CASE

Question 8

What is the J point?

Answer 8

The junction between the QRS (end of depolarization) and the ST segment

Question 9

What is an elevated J point?

Answer 9

J point that is above elevation of the PR segment. The ST segment is horizontal though.

Can be a normal finding in healthy young patients, but it can signify the beginning of ST elevation

Question 10

What 2 factors tends to suggest a non-concerning, normal variant J point elevation on a 12 point lead?

Answer 10

1. The patient is young
2. The J-point is diffuse throughout random parts of the lead (unlikely to infarct the entire heart)

Question 11

What is considered the first negative deflection?

Answer 11

Q wave

Question 12

What 2 criteria are necessary to be considered a pathologic Q wave?

Answer 12

1) at least 1 box wide (0.04 seconds)
2) depth at least 1/3 the QRS complex (dips down at least 1/3 the total it goes back up to)

Question 13

What is a pathologic Q wave indicative of?

Answer 13

Late stage MI

Question 14

How do you localize an infarction?

Answer 14

The abnormalities are in a WHOLE group

if in one lead, there is NOT an infarction, because the groups are looking at the same part of the heart.

Question 15

What are the anterior leads?

Answer 15

V2, V3, V4 (LAD lesion)

Question 16

What are the lateral leads?

Answer 16

I, aVL, V5, V6 (Circulation)

sometimes just I, aVL or V5 and V6

Question 17

What are the inferior leads?

Answer 17

II, III, aVF (RCA lesion)

Question 18

What are the Right-sided leads?

Answer 18

aVR, V1

Question 19

What are the septal leads?

Answer 19

V2, V3 (LAD lesion)

Question 20

What are reciprocal changes?

Answer 20

One side is infracting (so the depolarization and repolarization are abnormal), so the other side of the heart will compensate:

example: ST elevation on one side of the heart leads to ST depressions (opposite)

The ST elevations are the problem, and the ST depression is the heart’s response, not the other way around

Question 21

are reciprocal changes always present?

Answer 21

No - but if present, it is highly suggestive of MI

Question 22

If you have an inferior wall MI, where do you see reciprocal changes?

Answer 22

Anterior or lateral walls

Question 23

MI on which wall(s) of the heart leads to inferior reciprocal changes?

Answer 23

ALL OF THEM, except for the inferior wall itself

Septal
Anterior
Lateral

Question 24

What are the 3 steps of diagnosing a STEMI/MI?

Answer 24

1. Look at entire EKG for T wave, ST segment changes – up or down, or pathologic Q waves
2. If changes are noted, determine if the change is present in a group of leads
3. If there is ST segment elevation in a group of leads, look for reciprocal ST segment depression in another group to support diagnosis of STEMI