Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

EKG Final > Myocardial Ischemia and Infarction > Flashcards

Myocardial Ischemia and Infarction Flashcards

1
Q

_______ deliver blood to myocardial cells

_______ return deoxygenated blood to RA via _______

A

Coronary arteries

Coronary veins

Coronary sinus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Coronary blood flow is increased through ________ to meet increased myocardial oxygen demands

A

Vasodilation

Myocardial O2 extraction relatively high at rest (>2/3 max) compared to skeletal muscle (<1/3 max)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What does a normal q wave look like?

A

First negative deflection following PR segment

Amplitude of q wave is <25% of the R wave

Duration <0.04 s (40ms)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Flat line that follows QRS complex

A

ST segment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Where the QRS complex meets the ST segment

A

J point

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What does a normal T wave look like?

A

Slightly asymmetrical

Oriented in same direction as preceding QRS complex

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the maximum height for a normal T wave?

A

5mm in limb leads

10mm in precordial leads

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Myocardial ischemia results from…

A

Decreased oxygen and nutrient delivery to the myocardium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Myocardial ischemia can be reversed if…

A

Supply of oxygen and nutrients is restored

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Myocardial ischemia can be recognized by…

A

ST segment and T wave changes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Myocardial ischemia generally appears first in the ______ region

A

Sub-endocardial

Deeper myocardial layers are farthest from the blood supply and exposed to greater wall tension

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Causes of myocardial ischemia

A

Atherosclerosis

Vasospasm

Thrombosis and embolism

Decreased ventricular filling time (tachycardia)

Decreased filling pressure in coronary arteries (severe HTN or aortic valve disease)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are the different ischemic sequelae?

A

Non-MI new onset angina (subendocardial ischemia with transient ST depression)

Non-MI variant angina (transmural ischemia with transient ST elevation)

Non-Q MI (NSTEMI) - ST depression or T-wave changes or normal ECG

Q-wave MI (STEMI) - Typical evolution of ST-T changes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

In which ischemic sequelae will you see increased troponins?

A

NSTEMI and STEMI

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Myocardial injury results if…

A

Ischemia progresses unresolved or untreated

Injury is a greater degree of cell damage than ischemia but w/o actual cell death

ST-T changes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Define myocardial infarction

A

Death of myocardial cells with release of enzymatic break-down products of cell death
• Troponin
• CK-MB
• Myoglobin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What happens if a patient survives their myocardial infarction?

A

The infarcted tissue is replaced with scar tissue

ECG may show Q waves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are the different degrees of myocardial oxygen deprivation?

A

Ischemia (reversible, no permanent damage)

Injury (prolonged ischemia, onset of cellular damage, but no necrosis)

Infarction (death of injured cells, release of enzymes into circulation)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Depolarization normally proceeds in an ______ to ______ direction

A

Endocardium to epicardial

Conduction system is within in the sub-endocardial tissue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Repolarization usually proceeds from an _____ to _____ direction

A

Epicardial to endocardial

Coronary circulation is on the epicardial surface

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

General ECG indicators for ischemia

A

Inverted T wave

Tall, peaked symmetrical T wave

Depressed ST segment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

General ECG indicators of myocardial injury

A

ST segment changes (ie elevated ST segment)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

General ECG indicators of myocardial infarction

A

Q wave changes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is transmural ischemia?

A

Ischemia involving the entire myocardial wall

More significant, with repolarization taking longer in sub epicardial layers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

With transmural ischemia, T waves are ….

A

Symmetrical

Repolarization takes longer but also reverses direction (becomes endocardial-to-epicardial); results in T-wave inversion in leads overlying the ischemic regions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

T-wave inversion occurs with ischemia because…

A

Ischemic tissue does not repolarize normally

Ischemic T wave is more symmetrical than a normal T wave

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

RAD and asymmetrical T waves are seen in…

A

RVH with Strain Pattern (another cause of T wave inversion)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

When might you see peaked (or hyperacute) T waves?

A

In early stages of acute myocardial infarction
(>5mm in limb leads or >10mm in precordial leads)

Within a short time during evolution of an acute MI (~2 hours), T waves invert

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

ST segment depression may or may not include…

A

T wave inversion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

How do you determine if ST segment is elevated or depressed?

A

Compare the ST segment to the PR segment

Significant if ST segment is:
• >1mm below baseline measured 0.04s to right of J point
• In 2 or more contiguous leads

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Subendocardial ischemia, injury, and infarct involves…

A

The inner layer of the heart, but does not extend through the entire ventricular wall

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Progressive subendocardial ischemia and injury may progress to…

A

A subendocardial myocardial infarction

Also called a non-Q wave infarction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Flat ST segment depression can result from…

A

Subendocardial injury or infarction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

ST segment elevation indicates ….

A

Myocardial injury, and may indicate that infarction is in progress

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What is considered significant ST segment elevation?

A

> 1 mm above baseline measured 0.04s to the right of J-point in 2 or more contiguous leads

36
Q

In addition to MIs, ST segment elevation is seen in…

A 
Ventricular hypertrophy
Conduction abnormalities
Pulmonary embolism
Spontaneous pneumothorax
Intracranial hemorrhage
Hyperkalemia
Pericarditis
37
Q

Diffuse ST segment elevation = ________

A

Pericarditis, especially if flat or concave, angled back down to the next QRS complex

38
Q

Pathologic Q waves indicate presence of …

A

Irreversible myocardial damage or MI

39
Q

Q waves are considered pathologic if…

A

> 0.04s duration
OR
At least 1/3 of the height of R wave in the same QRS complex

AND
Present in 2 or more contiguous leads

40
Q

Why do you see pathologic Q waves with infarctions?

A

Infarcted areas of heart fail to depolarize (become electrically silent) as they are functionally dead

May take hours or days to develop

May persist for life

41
Q

Summary of ECG changes in ischemia

A
  • T wave inversion (due to delayed repolarization)
  • Symmetrical, peaked T waves
  • ST segment depression
42
Q

Summary of ECG changes in myocardial injury

A

ST elevation in leads facing injury (due to incomplete depolarization)

43
Q

Summary of ECG changes in infarction

A

Enlarging or new Q waves due to electrically silent infarcted tissue

44
Q

Necrosis of myocardial cells due to blockage of coronary artery or branch

A

Myocardial infarction

45
Q

Q wave infarcts are characterized by….

A

More extensive damage

Transmural

46
Q

Non-Q wave infarcts are characterized by….

A

Less extensive damage

Subendocardial

47
Q

Non-Q wave MI’s can be recognized by…

A

Evolving ST segment and T wave changes without Q waves

Evolving ST-T changes may include a variety of patterns

48
Q

Non-Q Wave MI’s are seen in patients with ________ symptoms and elevation in _________

A

Typical/angina chest pain

Myocardial-specific enzymes

49
Q

The right coronary artery perfuses the ….

A

Right atrium

Right ventricle

Inferior and posterior walls of the left ventricle

50
Q

The left main coronary artery divides into _______ and ______

A

Left anterior descending (LAD) branch

Left circumflex (LCX) branch

51
Q

The LAD perfuses the….

A

Anterior and lateral left ventricle

Anterior 2/3 of ventricular septum

R&L bundle branches

52
Q

The left circumflex artery perfuses the…

A

Left atrium

Anterolateral, posterolateral, and posterior LV

53
Q

Which coronary artery perfuses the:

Right atrium

A

Right coronary artery

54
Q

Which coronary artery perfuses the:

Right ventricle

A

Right coronary artery

55
Q

Which coronary artery perfuses the:

Inferior and posterior walls of LV

A

Right coronary artery

56
Q

Which coronary artery perfuses the:

Anterior and lateral left ventricle

A

LAD

57
Q

Which coronary artery perfuses the:

Anterior 2/3 of ventricular septum

A

LAD

58
Q

Which coronary artery perfuses the:

R&L bundle branches

A

LAD

59
Q

Which coronary artery perfuses the:

Left atrium

A

Left circumflex artery

60
Q

Which coronary artery perfuses the:

Anterolateral, posterolateral and posterior LV

A

Left circumflex artery

61
Q

What type of MI is the patient having:

Changes in precordial leads (V1-4) with reciprocal changes in inferior leads

A

Anterior MI

62
Q

Anterior MI’s are subdivided into…

A

Septal (V1-V2)

Anteroseptal (V1-V3)

Anterolateral (V1 or V2 to V5 or V6)

63
Q

What type of MI is the patient having:

Changes in Lead I, aVL, V5-6 with reciprocal changes in inferior leads

A

Lateral MI (aka lateral wall MI)

64
Q

What type of MI is the patient having:

Changes in leads II, III, and aVF with reciprocal changes in anterolateral leads

A

Inferior MI

65
Q

What type of MI is the patient having:

Reciprocal changes in V1-2, tall R waves with ST depression in these leads

A

Posterior MI

66
Q

What is the usual ECG evolution of a Q-wave MI?

A
  1. Normal ECG
  2. Hyperacute T wave changes w/ ST elevation
  3. Marked ST elevation w/ hyperacute T wave changes
  4. Pathologic Q waves, less ST elevation, terminal T wave inversion
  5. Pathologic Q waves, T wave inversion
  6. Pathologic Q waves, upright T waves
67
Q

MI damage is reversible until…

A

Pathologic Q waves appear

68
Q

Anterior MI’s are characterized by…

A

Damage to anterior surface of LV

ST segment elevation, T wave inversion, and development of pathologic Q waves in leads V1-4

69
Q

An anterior MI is called ______ if V1-3 are involved

A

Anteroseptal

70
Q

An anterior MI is called _______ if V1 is not involved

A

Anterior

71
Q

An anterior MI is called _______ if V4-6 is involved

A

Anterolateral

72
Q

Which leads are over the ventricular septum?

A

V1, V2, and V3

Ischemic changes in these leads and possibly in the adjacent precordial leads, are often considered to be septal infarctions

73
Q

Ischemic changes in V1 and V2 are considered …

A

Septal MI

74
Q

Ischemic changes in V1-3 are considered…

A

Anteroseptal MI

75
Q

Lateral MIs are characterized by…

A

ST segment elevation, T wave inversion, and the development of pathologic Q waves in leads I, aVL, V5 and V6

76
Q

Inferior MI’s are characterized by…

A

ST segment elevation, T wave inversion, and development of pathologic Q waves in leads II, III, and aVf

77
Q

How do you differentiate a new vs an old MI?

A

Following recovery from an MI, the ST segment is the earliest to normalize, then the T wave, but the Q wave usually persists

78
Q

Classic changes of necrosis (_________), injury (________) and ischemia (__________) may all be seen during the evolution of acute infarctions

A

Q waves

ST elevation

T wave inversion

79
Q

Q waves in the absence of ST segment and T wave abnormality generally indicates….

A

Prior “healed” or “old” infarction

80
Q

How do you recognize posterior MIs?

A

Lack of ECG leads there, so you look for reciprocal changes in leads V1 and V2

Look for abnormal R waves in V1 and V2 with ST depression

81
Q

What are the criteria for abnormal R waves (reciprocal changes) seen in Posterior MIs?

A

R waves in V1/V2 that are:
• ≥ 0.04s in duration
• R≥S
• Patient >30 yo

No signs of RVH

Sometimes see Q waves in V6 too

82
Q

You should have a high degree of suspicion for a posterior wall MI if….

A

ST depression in V1-3

83
Q

Where will you see reciprocal ST depression:

For Anterior MI (V1-4)

A

Inferior leads (II, III, aVF)

84
Q

Where will you see reciprocal ST depression:

Anteroseptal MI (V1-2)

A

Inferior leads (II, III, aVF) or lateral leads (I, aVL, V5, V6)

85
Q

Where will you see reciprocal ST depression:

Lateral MI (I, aVL, V5-6)

A

Inferior leads (II, III, aVF) and in some cases leads V1-2

86
Q

Where will you see reciprocal ST depression:

Inferior MI (II, III, aVF)

A

Lead I and aVL (in some cases leads V1-3)

EKG Final (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions