Myocardial Infarction - Johnston Flashcards

1
Q

Inverted T waves

Where usually?

A

Ischemia

- Chest leads (closest to ventricles)

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2
Q

Causes of MI (occlusion)

A
  • Atherosclerosis
  • Vasospasm
  • Vasculitis
  • Dissection
  • Genetics
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3
Q

Chest pain, etc. not relieved by nitro or rest…Think what?

A

MI

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4
Q

Silent MI…think what?

A

Diabetics, elderly women

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5
Q

4 signs of new heart failure

A
  • S3 gallop
  • Crackles in lungs
  • Increased JVD
  • New murmur
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6
Q

Autonomic responses for…

Anterior MI vs. Inferior MI

A

Anterior - sympathetic (tachy, HTN)

Inferior - parasympathetic (bradycardia, hypotension)

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7
Q

EKG signs of STEMI

A
  • Men - > 2mm STE (V2-V3)
  • Women - > 1.5mm STE (2 or more contiguous leads)
  • Maybe new LBBB
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8
Q

NSTEMI or NST ACS - EKG

A

ST depression, T wave inversion

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9
Q

Distinguishing NSTEMI from NSTE ACS

A
NSTEMI - elevated cardiac enzymes
NSTE ACS (angina) - normal cardiac enzymes
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10
Q

Early phase of STEMI - EKG

What are they?

A

Tall hyperacute T waves

- Upward, slightly curved pattern

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11
Q

Causes of inverted T waves (7)

A
  • Normal in children (V1-3)
  • Myocardial ischemia
  • BBB
  • Ventricular hyper. w/ strain
  • P.E.
  • Hypertrophic cardiomy.
  • Raised ICP
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12
Q

How to tell where the acute MI is occurring?

A

Where are the inverted T waves?

  • Inferior = 2, 3, F
  • Lateral = 1, L, V5-6
  • Anterior = V2-6
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13
Q

ANY T-wave inversion in leads _____ is considered pathological

A

V2-V6

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14
Q

Other causes of STE?

A
  • Pericarditis
  • LVH w/ J point elevation
  • Normal variant early repol.
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15
Q

Pericarditis - EKG

A

ST segment elevation, usually flat or slightly concave, with potentially the whole T wave elevated to the next P wave

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16
Q

Causes of ST depression?

A
  • Subendocardial ischemia
  • Stress test
  • Digitalis toxicity
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17
Q

Diagnostic feature for infarction on EKG

A

Significant Q waves (NECROSIS) in the infarcted area leads

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18
Q

What is a “significant” Q wave?

A

> 1mm wide or 1/3 the QRS amplitude tall

19
Q

A normal Q wave in leads ___ is INSIGNIFICANT

A

AVR, V5-6

20
Q

SO, 3 things to look for when suspecting MI?

A
  • Significant Q waves
  • STE or ST depression
  • Inverted T waves
21
Q

Describe why a Q wave means necrosis?

A

If the cardiac tissue under the lead is necrotic, there is no electrical activity, so the lead picks up the septal impulse moving away towards the other ventricle

22
Q

ST elevation in terms of MI means what?

A

ACUTE

23
Q

How to detect an acute posterior infarction?

A

The OPPOSITE is true of that in an ANTERIOR MI…

 - in V1-2, QRS is "flipped"
 - in V1-2, R wave is up
 - "STE" --> ST depression
24
Q

Significant Q in 1 and AVL

A

Lateral MI

25
Q

Significant Q in V1-V4

A

Anterior MI

26
Q

Significant Q in 2, 3, F

A

Inferior MI

27
Q

Large R in V1, V2

Mirror test

A

Posterior MI

28
Q

Signs of MI can be obscured by ____

A

LBBB

29
Q

Persistent ST elevation (over 2 weeks)

A

Ventricular aneurysm (after an MI)

30
Q

Standard care for STEMI

A
  • EKG and continuous cardiac monitoring
  • IVs inserted
  • Cardiac enzymes, blood panels, clotting times
  • Reperfusion, fibrinolysis
  • Heparin, MONA
31
Q

How to monitor reperfusion therapy?

A

Must see resolving ST elevation within 1-2 hours

32
Q

Major risk factor for fibrinolytic therapy

A

Intracranial hemorrhage

33
Q

Good times to use fibrinolysis

A

STEMI or new LBBB (within 12 hours)

34
Q

When to use a beta blocker in heart failure or MI?

A

If BP or HR are elevated due to compensatory response

35
Q

When to use an ACEI in HF or MI?

A

If EF is low or BP is high

36
Q

Previous Hx of MI, now hurts to breathe and feels better leaning forward

Treatment?

A

Dressler syndrome (immune-mediated)

Aspirin, NSAID

37
Q

Previous MI –> fibrinolytic therapy –> ventricular tachycardia

A

Accelerated idioventricular rhythm (AIVR)

38
Q

Arrhythmias associated w/ inferior MI

A

Sinus bradycardia, Wenckebach AV block

39
Q

Differential diagnosis for a STEMI

A
  • Pericarditis
  • Myocarditis
  • Takotsubo (stress-induced) syndrome
  • Early repolarization
40
Q

Initial pharma treatments for STEMI

A
  • Aspirin (unless contraindicated)

- IV Heparin or antiplatelet agent

41
Q

Full pharma list of treatments for STEMI

A
  • Nitro
  • Oxygen
  • Morphine
  • Aspirin
  • BB - IF high BP or high HR
  • Stool softener
  • ACEI - IF low EF or high BP
  • Thrombolytic therapy
42
Q

Most common rhythm disturbances after an MI

A

V tach

V fib

43
Q

What can occur on EKG after fibrinolytic therapy? Serious?

A

Slow V tach (60-100)

Benign

44
Q

Most common cause of death after MI

A

Heart failure