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EKG > L6: Myocardial Ischemia and Infarction > Flashcards

L6: Myocardial Ischemia and Infarction Flashcards

1
Q

Normal q Wave

A

Amplitude <25% of R wave

Duration

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2
Q

Max T wave heights

A

Limb leads→ 5 mm

Precordial leads→ 10 mm

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3
Q

ECG changes seen with ischemia

A

T wave inversion (delayed repolarization)

Symmetrical, peaked T waves

ST segment depression

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4
Q

ECG changes seen with injury

A

ST elevation in leads facing injury (incomplete depolarization)

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5
Q

ECG changes seen with infarct

A

Enlarging or new Q waves (electrically silent infarcted tissue)

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6
Q

Ischemia appears in the ______ first

A

Sub-endocardial region

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

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7
Q

Q waves on ECG without other changes

A

Old MI

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8
Q

Symmetrical T wave inversion =

A

Transmural ischemia

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9
Q

Asymmetrical T wave inversion=

A

RVH with strain

also has RAD

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10
Q

T waves are initially _______ and take two hours to _____

A

Initially: hyperacute (peaked)

2 hours after onset: inversion

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11
Q

Criteria for ST segment depression

A

ST segment > 1 mm below baseline measured .04 s (40 ms) to right of J point in 2 or more contiguous leads

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12
Q

Criteria for flat ST segment depression

A

Flat ST segment with slight T wave inversion

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13
Q

ST segment depression occurs during

A

Ischemia

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14
Q

ST segment elevation occurs during

A

Injury or infarction

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15
Q

Flat ST segment depression is seen with

A

Sub-endocardial ischemia and injury

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16
Q

Criteria for ST segment elevation

A

> 1 mm above baseline measured
0.04 s (40 ms) to right of J-point, in
2 or more contiguous leads

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17
Q

Other non-MI causes of ST segment elevation

A 
Ventricular hypertrophy
Conduction abnormalities
Pulmonary embolism
Spontaneous pneumothorax
Intracranial hemorrhage
Hyperkalemia
***Pericarditis***
18
Q

ECG of Pericarditis

A

Diffuse ST segment elevation
Segment is flat or concave
ST/T waves gradually angle back down to next QRS complex

19
Q

Pathologic Q waves take _____ to develop

A

Hours or days to develop +/- persist for life

20
Q

What makes a Q wave pathologic?

A

> 0.04 s (40 ms) duration
At least 1/3 the height of R wave in same QRS
complex
AND
Present in 2 or more
contiguous leads
The initial >04 s QRS vector points away from the site of infarct

21
Q

A Q wave infarct is

A

Transmural (more extensive)

STEMI

22
Q

A Non-Q wave infarct is

A

Subendocardial (less extensvie)

NSTEMI

23
Q

Right coronary artery perfuses…

A

right atrium
right ventricle
inferior and posterior walls of left ventricle

24
Q

Left anterior descending (LAD) perfuses

A

Anterior + lateral left ventricle
Anterior ⅔ of ventricular septum
Right + Left bundle branches

25
Q

Left circumflex (LCX) perfuses

A

Left atrium

Anterolateral, posterolateral, posterior left ventricle

26
Q

Lateral leads

A

I, aVL, V5, V6

27
Q

Anterior leads

A

V1, V2, V3, V4

28
Q

Inferior leads

A

II, III, aVF

29
Q

Septal leads

A

V1, V2, V3

30
Q

Anterior MI

A

No V1

V2, V3 changes

31
Q

Anterolateral MI must include

A

V4-V6

32
Q

Septal MI

A

V1, V2

33
Q

Anteroseptal MI

A

V1-3

34
Q

Anterolateral MI

A

V1/2 to V5/6

35
Q

Anterolateral MI reciprocal changes

A

Inferior leads

36
Q

Lateral MI reciprocal changes

A

Inferior leads

37
Q

Inferior MI reciprocal changes

A

Anterolateral leds

38
Q

Posterior MI reciprocal changes

A

V1-2

Tall R waves
R waves > .04
R>S
Patient > 30 years

39
Q

ST depression in V1-3

A

High index of suspicion for posterior MI

40
Q

New vs Old MI

A

New→ Q waves, ST elevation, T wave inversion

Old→ Q wave persists in absence of ST segment or T wave abnormalities

EKG (10 decks)

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