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BCEHS CPGs > C01: Acute Coronary Syndrome (and ECGs) > Flashcards

C01: Acute Coronary Syndrome (and ECGs) Flashcards

1
Q

How does management of pain, nausea, and limitation of patient exertion have a positive effect on morbidity/mortality in ACS?

A

Limits myocardial oxygen demand

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2
Q

Describe preferred placement of the therapy electrodes if you suspect your patient will be seen urgently in the cath lab

A

Anterolateral pad position with wires travelling cephalad (toward the head)

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3
Q

Which region should be avoided for IV cannulation if your patient is being transported/transferred for angiography (cath lab)

A

Avoid the distal third of the right forearm, this is frequently the insertion site for PCI
Placement in the proximal right forearm or antecubital fossa is not an issue

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4
Q

Describe the role of nitroglycerin in management of ACS

A
  • Given for pain relief
  • Does NOT improve outcomes, and may worsen them in some cases
  • If not effective after first few doses, further doses are unlikely to produce benefit
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5
Q

What are the three sub-classifications of ACS?

A
  • Unstable angina
  • NSTEMI
  • STEMI
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6
Q

What ECG changes are typically seen in NSTEMI?

A
  • non-specific ischemic findings including; T-wave inversions, ST depressions, transient ST elevations, or hyperacute T-waves
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7
Q

A patient presents with signs/symptoms of ACS. They are on daily apixaban therapy and have been advised to avoid ASA while taking it. Should you give ASA anyways?

A

Yes!
“Patients on oral anticoagulant therapies are often told by their physician to avoid ASA. In the setting of suspected or known ACS, the antiplatelet activity of ASA is of more importance than the temporary rise in INR.”

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8
Q

What is an appropriate oxygen target for a patient with signs of ACS?

A

target 94% or greater. Ideally, do not exceed 98%

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9
Q

What are indications for NTG administration in ACS for PCP/EMR?

A
  • SBP must be greater than 110 mmHg
  • HR must be between 50-150bpm
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10
Q

What is the classic “tetrad” of treatments for ACS?

A
  • MONA/FONA
  • Fentanyl (0.5-1mcg/kg IV q.5m)
  • Oxygen (target SpO2 94% or greater)
  • Nitroglycerin (0.4mg q.3-5m SL, SBP 110 or greater, HR 50-150)
  • ASA (160mg PO, dispatch instructs to take 320mg)
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11
Q

Summarize diagnostic ECG criteria for STEMI
* include criteria for age/sex
* do not include equivalents/mimics

A
  • ST elevation in 2 or more anatomically contiguous leads, meeting the following criteria:
  • Men 40 or greater: 2.5mm in V2/V3, 1mm in all other leads
  • Men less than 40: 2.0mm in V2/V3, 1mm in all other leads
  • Women: 1.5mm in V2/V3, 1mm in all other leads
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12
Q

Can reciprocal ST depression be used to rule in or rule out ACS?

A

NO!
This is no longer best practice. Recpiprocal depression adds little specificity, at an unacceptable cost to sensitivity

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13
Q

Which ECG leads require higher levels of ST elevation than others to be considered diagnostic of STEMI?

A

V2/V3
*Men 40 or greater: 2.5mm in V2/V3, 1mm in all other leads
* Men less than 40: 2.0mm in V2/V3, 1mm in all other leads
* Women: 1.5mm in V2/V3, 1mm in all other leads

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14
Q

What five patterns are considered STEMI equivalents by BCEHS? Which one of these five is typically seen as an NSTEMI, rather than STEMI equivalent in the medical community-at-large?

A
  • De Winter’s T-waves
  • Positive Sgarbossa Criteria (LBBB or V-paced Rhythm)
  • aVR STEMI pattern
  • Posterior STEMI pattern
  • Wellen’s syndrome (Generally considered to be a NSTEMI equivalent)
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15
Q

Describe properties of De Winter’s T-waves, including:
* Which leads to be considered
* Characteristic morphology
* Quantitative findings (i.e. degree of elevation or depression)

A
  • Should only be considered in the precordial leads
  • Characteristic upsloping ST depression with tall, prominent T-waves in any or all of the precordial leads
  • No ST elevation in the precordial leads
  • 0.5-1mm STE in aVR
  • ST depression must be 1mm or greater
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16
Q

What is the clinical significance of De Winter T-waves?

A
  • Considered a STEMI equivalent!
  • Early finding in evolving STEMI
  • Transmit early and treat as STEMI
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17
Q

You respond to a patient with cardiac-suggestive chest pain and the following 12-lead ECG is acquired.
* What are the relevant findings?
* Should you notify/bypass?
* How will you treat?

A
  • De Winter T-waves are seen in V2-V4, as well as widespread ST depression with STE greater than 1mm in aVR
  • This is a STEMI equivalent (x2)
  • YES! You should immediately transmit and advocate for PCI bypass
  • Treat per standard ACS package: MONA/FONA, treat shock, prepare for resuscitation
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18
Q

You respond to a patient with cardiac-suggestive chest pain and the following 12-lead ECG is acquired.
* What are the relevant findings?
* Should you notify/bypass?
* How will you treat?

A
  • De Winter T-waves are seen in V3-V5, as well as STE greater than 1mm in aVR (an expected finding with De Winter’s T-waves)
  • This is a STEMI equivalent
  • YES! You should immediately transmit and advocate for PCI bypass
  • Treat per standard ACS package: MONA/FONA, treat shock, prepare for resuscitation
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19
Q

Describe the original, and Smith’s-modified Sgarbossa criteria, including;
* Indications for using the Sgarbossa criteria
* The original point-based scoring system for clinical significance
* How Smith’s rule impacts clinical scoring

A
  • Used to identify AMI in the presence of LBBB or a paced rhythm
  • The original criteria are as follows:
    1. Concordant STE of 1mm or greater in ANY lead (5 points)
    2. Discordant ST depression in V1-V3 (3 points)
    3. Excessively discordant ST elevation (more than 5mm) in any lead (2 points)
  • 3 points or more were required for clinical significance
  • Smith’s-modified rule replaces the third Sgarbossa criteria. Excessive discordance is redefined as ST/S ratio greater than 0.25
  • Smith’s-modified does away with the points system, any finding is clinically significant
20
Q

Compare sensitivity and specificity of Sgarbossa’s original criteria and the Smith-modified rule

A
  • Both are essentially equally specific (91% vs. 90%). Smith’s-modified is substantially more sensitive (91% vs. 36%)
21
Q

You are responding to a patient with “chest pressure” and diaphoresis. You acquire the following 12-lead ECG.
* What are the relevant findings?
* Should you notify/bypass?
* How will you treat?

A
  • This is a LBBB with positive Smith-modified Sgarbossa criteria
  • There is excessive discordance in V3-V4 (ST/S greater than 0.25) and concordant STE in the inferior leads
  • This is a STEMI equivalent!
  • YES! You should immediately transmit and advocate for PCI bypass
  • Treat per standard ACS package: MONA/FONA, treat shock, prepare for resuscitation
22
Q

Describe ECG findings in aVR STEMI pattern

A
  • ST elevation in aVR ≥ 1mm
  • ST elevation in aVR ≥ V1
  • Widespread horizontal ST depression (often I, II, aVL, and V4-6)
  • aVR elevation in the presence of a tachycardia is often rate related and not suggestive of LMCA occlusion
23
Q

Which leads are MOST likely to show ST depression in aVR STEMI pattern?

A

The anterolateral leads; I, II, aVL, and V4-6

24
Q

What is the clinical significance of an aVR STEMI pattern?

A

In the context of widespread ST depression + symptoms of myocardial ischemia:
* STE in aVR ≥ 1mm indicates proximal LAD / LMCA occlusion or severe 3VD
* STE in aVR ≥ 1mm predicts the need for CABG
* STE in aVR ≥ V1 differentiates LMCA from proximal LAD occlusion
* Absence of ST elevation in aVR almost entirely excludes a significant LMCA lesion

25
Q

With regards to aVR STEMI pattern, is the degree of ST elevation in aVR correlated to the degree of morbidity/mortality?

A

YES!!!
* STE in aVR ≥ 0.5mm is associated with a 4-fold increase in mortality
* STE in aVR ≥ 1mm is associated with a 6- to 7-fold increase in mortality
* STE in aVR ≥ 1.5mm has been associated with mortalities ranging from 20-75%

26
Q

What two non-ecg conditions should be met prior to considering a provisional Dx of AMI in aVR STEMI pattern?

A
  • There should be other clinical findings of ACS (ex: cardiac-suggestive chest pain)
  • The patient can not have a clinically-significant tachycardia
27
Q

Describe ECG findings in posterior STEMI pattern, including
* relevant leads
* quantitative criteria (i.e. how much STE is required)

A
  • Precordial ST Depression V1-4 > 1mm (sensitive). As always, 2 or mroe contiguous leads are required
  • ST Elevation in V7/8/9 > 0.5mm adds specificity
28
Q

Are posterior leads required to diagnose posterior STEMI?

A

NO!
posterior leads add specificity, but are not required and should not delay treatment/transport

29
Q

Describe both clinical and ECG findings in Wellen’s syndrome, including:
* characterisitic physical findings
* ECG findings for both type A and type B patterns
* Which leads are involved in both cases

A
  • Following an ischemic event suggestive of unstable angina. ECG findings are generally only visible once patient is pain free. Note that the presenting complaint may be resolved syncope!
  • TYPE A: Biphasic T waves, most commonly in leads V2 and V3. Presents with upstroke/down-stroke.
  • TYPE B: 76% of the time, deep inversion of the T-wave segment in the precordial leads, V1-V4.
30
Q

Describe the clinical significance of Wellen’s syndrome

A
  • Pre-infarction stage of coronary artery disease suggesting 80-90% LAD occlusion that often progresses to a devastating anterior wall MI.
  • Most sources consider this to be a NSTEMI equivalent rather than a STEMI equivalent
  • When in doubt; transmit, call, and advocate
31
Q

You respond to a patient who initially complained of ischemic chest pain, but now states their pain has spontaneously resolved. Their 12-lead ECG shows deep T-wave inversions in V1-V4. What is the significance of this finding?

A
  • This is characterisitic of a Wellen’s syndrome with TYPE B pattern
  • Suggests 80-90% LAD occlusion that often progresses to a devastating anterior wall MI
  • Treat as NSTEMI/STEMI equivalent
32
Q

What four ECG patterns are recognized as STEMI mimics by BCEHS? Which one of these four may ALSO be considered a STEMI equivalent if certain criteria are met?

A
  • Benign early repolarization (BER)
  • Pericarditis
  • Left Ventricular Hypertrophy (LVH)
  • Left bundle branch block (LBBB); may be a STEMI equivalent if Sgarbossa/Smith’s-modified criteria are met
33
Q

Describe characteristic ECG features of benign early repolarization (BER), including;
* Key features of morphology
* Which leads are affected
* which patients should not be considered for a provisional Dx of BER

A
  • Widespread concave ST elevation with J point elevation
  • May have ‘fish-hooked’ Osborne wave
  • No reciprocal ST depression to suggest STEMI (except in aVR)
  • ST changes are relatively stable over time (no progression on serial ECG tracings)
  • BER should only be considered in younger patients, typically males. Use extreme caution for patients 50 or older, and NEVER consider BER for patients over 70!
34
Q

What is the clinical significance of BER?

A
  • None! It is a benign ECG finding, typically in younger, healthy males.
  • Thought to be caused by highly excitable ion channels (particularly due to presence of testosterone) leading to rapid depolarization and, consequently, simultaneous depolarization and repolarization
  • BER should only be considered in younger patients, typically males. Use extreme caution for patients 50 or older, and NEVER consider BER for patients over 70!
35
Q

Describe characteristic physical and ECG findings in pericarditis

A
  • Sharp, pleuritic sub-sternal pain worsening when supine. May have a pleural friction rub. May demonstrate Beck’s triad - hypotension, muffled heart sounds, and JVD. Investigate for recent myocardial insult (ttraumatic or infectious)
  • Widespread concave ST elevation and PR depression
  • Reciprocal ST depression and PR elevation in lead aVR
  • Sinus tachycardia is also common in acute pericarditis due to pain and/or pericardial effusion
36
Q

How should ST elevation be measured in pericarditis?

A
  • Using the TP segment!
  • Comparing to the PR segment will often lead to false findings due to characteristic ST depression in pericarditis
  • Spodick’s sign (a down-sloping TP and PR) is often present
37
Q

Describe ECG findings in LVH, including;
* Voltage criteria
* Strain criteria

A
  • Voltage criteria: BCEHS uses the following: S(V1 or V2) + R(V5 or V6) > 35mm
  • This is a modification of the Sokolov-Lyon criteria (normally V2 not included)
  • Strain Criteria:
    1. ST Elevation V1-4
    1. ST Depression / Inverted T waves V5 and V6
    1. Generally proceeds from most elevated V1/2 to most depressed V6
38
Q

Describe characteristic ECG findings in LBBB

A
  • QRS > 120ms
  • Prominent S (V1-3) / prominent R (V5/6, I/aVL)
  • ST Elevation common in V1-4
39
Q

Is a new LBBB considered a STEMI equivalent?

A

No! This is old practice!
Check for the presence of Sgarbossa/Smith’s-modified criteria

40
Q

You respond to a patient with chest pain and the following 12-lead ECG is acquired:
* What are the relevant findings?
* Should you transmit/bypass?
* How should you treat?

A
  • This is a LBBB which is negative for Sgarbossa/Smith criteria
  • LBBB is not considered a STEMI equivalent. You are not required to transmit/bypass, but this could be appropriate if other clinical findings are present; always advocate for your patient.
  • Investigate for other causes of chest pain. Treat per ACS guidelines if findings are supportive.
41
Q

Which leads are considered “anatomically contiguous” for purposes of STEMI recognition? (i.e. what are the groupings of anatomical regions of the heart by leads?)

A
  • Inferior: II, III, aVF
  • Septal: V1, V2
  • Anterior: V3-V4
  • Lateral: V5, V6, I, aVL
  • Note that any contiguous grouping of V1-V6 is considered significant (ex: V2+V3)
42
Q

You respond to a patient with chest pain and the following 12-lead ECG is acquired:
* What are the relevant findings?
* Should you transmit/bypass?
* How should you treat?

A
  • This is a paced rhythm which is positive for Sgarbossa/Smith criteria (concordant ST depression in precordial leads)
  • This is a STEMI equivalent. Transmit early and bypass to a PCI center
  • Treat as ACS; MONA/FONA, treat for shock, prepare to resuscitate
43
Q

You respond to a patient with chest pain and the following 12-lead ECG is acquired:
* What are the relevant findings?
* Should you transmit/bypass?
* How should you treat?

A
  • This is a LBBB which is negative for Sgarbossa/Smith criteria
  • LBBB is not considered a STEMI equivalent. You are not required to transmit/bypass, but this could be appropriate if other clinical findings are present; always advocate for your patient.
  • Investigate for other causes of chest pain. Treat per ACS guidelines if findings are supportive.
44
Q

You respond to a patient with chest pain and the following 12-lead ECG is acquired. The patient is a fit, 55M who complains of chest pain since their usual workout this morning:
* What are the relevant findings?
* Should you transmit/bypass?
* How should you treat?

A
  • This is likely BER (upsloping STE with osborne waves and high QRS voltages in a fit male). BER should be considered with caution in patients over 50, but this case fits the clinical picture.
  • This is a STEMI mimic. Do not transmit or bypass unless other evidence of ACS exists
  • Investigate for other causes of chest pain (likely MSK). Continue to monitor with serial 12-lead ECGs; dynamic ST changes are NOT characterisitic of BER and point to ACS!
45
Q

You respond to a patient with chest pain and the following 12-lead ECG is acquired:
* What are the relevant findings?
* Should you transmit/bypass?
* How should you treat?

A
  • ST-depression in V2-V4 suggests posterior STEMI
  • This is a STEMI equivalent! Transmit and bypass to a PCI center
  • Treat as ACS: MONA/FONA, treat for shock, prepare to resuscitate.
  • You may consider acquiring posterior leads V7-V9 to add specificity, but only if it does not delay transport
46
Q

You respond to a patient with chest pain and the following 12-lead ECG is acquired:
* What are the relevant findings?
* Should you transmit/bypass?
* How should you treat?

A
  • If you don’t know, you’re in trouble…..
  • This is an obvious inferior STEMI with posterior extension
  • Transmit and bypass immediately
  • Treat as ACS: MONA/FONA, treat for shock, prepare to resuscitate.

BCEHS CPGs (2 decks)

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