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Emergency Medicine > ECG Pearls > Flashcards

ECG Pearls Flashcards

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0
Q

Findings suggestive of PE (11) on ecg

A
  1. Sinus Tachycardia (44% pts)
  2. Incomplete or complete RBBB (18% pts)
  3. ST depression V1-3
  4. T wave inversion in V1-3, and inferior leads (34% pts)
  5. S1Q3T3 - not sen or spec
  6. RAD - 16% pts
  7. Dominant R wave in V1
  8. RAE - peaked P wave II>2.5mm (9% pts)
  9. CLockwise rotation - shift of R/S transition point towards V6
  10. Atrial tachyarrythmias - AFL, AFIB
  11. Non spec ST changes - 50% pts
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1
Q

Criteria for Brugada Syndrome

A
  • Type 1: coved STE >2 mm in greater than 1 of V1-V3 followed by negative T wave.
  • only ecg finding thats potentially diagnostic - called Brugada sign
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2
Q

What is Wellens?

A

Inverted or Biphasic T waves in V1-V3 indicating critical LAD occlusion
- Extremely high risk for extensive anterior wall MI within next 2-3 weeks
Type A: Deep symmetrical inverted T waves
Type B: Biphasic T wave with initial deflection +ve and terminal deflection negative.

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3
Q

What to look for when Syncope Patient (9)

On ecg

A
  1. Long QT
  2. Brugada Syndrome (Coved STE V1-3, TWI)
  3. Tachy/Brady Arrhythmia
  4. 2nd type II or 3rd deg HB
  5. WPW
  6. HOCM
  7. ACS
  8. arrhythmogenic right ventricular dysplasia (epsilon waves)
  9. PE
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4
Q

Scarbossa’s Criteria (MI in LBBB)

A
  1. Concordant STE >1mm in any lead with +ve QRS (5pts)
  2. Concordant STD >1mm in V1-V3 (3 pts)
  3. Excessive discordance STE >5mm (2pts)
    >3 points = 90% specificity for MI
    - need 3 or more points.
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5
Q

What is a sign of left main critical stenosis? On ecg

A

STE aVR

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6
Q

WPW ECG changes

A
  1. PR interval shortened
  2. Delta wave
  3. ST segment and T wave discordant changes
  4. Pseudo infarction pattern can be seen in 70% pts. due to negatively deflected delta waves in inf and ant leads (pseudo Q waves) or as a prominent R wave in V1-3 mimicking posterior infarction.
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8
Q

What are causes of LAD on ECG (3 main)

A
  1. LVH
  2. LAFB, LBBB
  3. Inferior MI (look for Q waves in inf leads)
  4. Pregnancy/obesity
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8
Q

What is the definition of Wide QRS?

How wide does the QRS have to be to be a BBB?

A

> 110ms

>120 ms

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9
Q

Causes RAD (11)

A 
Left posterior fascicular block
Lateral myocardial infarction
Right ventricular hypertrophy
Acute lung disease (e.g. PE)
Chronic lung disease (e.g. COPD)
Ventricular ectopy
Hyperkalaemia
Sodium-channel blocker toxicity
WPW syndrome
Normal in children or thin adults with a horizontally positioned heart
Dextrocardia
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10
Q

On ECG what is a normal P wave morphology in V1 and II?

A

Biphasic in V1, Positive in II and avF

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11
Q

On Ecg if wide QRS> 160 what 4 causes should you think of?

A
  1. Hyperkalemia
  2. Na channel blockage (give NaHCO3)
  3. Acidosis
  4. Intra-ventricular conduction delay (Bifasicular or trifascicular blocks)
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12
Q

What is Basset’s formula to calculate QTc?

A

QTc= QT/ square root (R-R interval)

However, this is a non-linear formula, obtained from data in only 39 young men, is not accurate, and over-corrects at high heart rates and under-corrects at low heart rates.

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13
Q

On ecg: what do you see in RAE? (P-pulmonale)

A

Peaked P wave with amplitude:
>2.5 in inf. leads (II*, III and aVF)
>1.5 mm in V1, V2

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14
Q

What ECG changes do you get with Hyperkalemia? (5)

A
  1. Peaked T waves
  2. Flat P wave
  3. Long PR
  4. Elevated ST
  5. Sine wave –>VF
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15
Q

What is the normal length of QT?

and how do you measure it?

A

QTc is prolonged if > 440ms in men
or > 460ms in women
QTc > 500 is associated with increased risk of torsades de pointes.

Measured from start of Q wave to end of T.

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16
Q

What are the ECG changes in Hypokalemia? (6)

A
  1. Flattened T wave and inversion
  2. Incr amplitutde of P wave
  3. Prolonged PR interval
  4. ST depression
  5. Promiment U waves (usu in precordial leads)
  6. Apparent Long QT (due to fusion of T and U = long QU interval)
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17
Q

What are ECG changes in pericarditis? (5)

A
  1. Diffuse STE (usu all except v1)
  2. Concave STE (smiley face)
  3. Elevation not >5mm
  4. PR depression in V6,II (specific)
  5. PR elevation in aVR = “knuckle sign”
  6. No Q waves or reciprocal changes
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18
Q

What are the ECG stages/evolution in pericarditis?

A

STE and PR depression
ST resolution
T wave inversion
Normalization

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19
Q

BER vs Pericarditis? What do you look for?

A

Pericariditis

  1. Generalized STE
  2. PR depression
  3. No fish hook - J point notch
  4. Normal sized T waves
  5. ST/T>0.25 (highly specific)

BER

  1. STE in precordial leads v2-V5
  2. No PR depression
  3. “fish hook” - j point notch
  4. Big T-waves
  5. ST/T <0.25 (b/c of big t waves)
20
Q

What is Amal Mattu’s 3 steps to differentiate STEMI from pericarditis?

A
  1. Look for ST depression (other than aVR and V1)- there should not be any reciprocal changes in Pericarditis
  2. Morphology of ST segment. Smiley face in pericarditis, frown face/tomb stone in STEMI
  3. STE III>II –> this is highly specific for MI

Then look for PR depression. But remember PR depression and PR elevation in aVR can occur in STEMI if there is atrial ischemia

21
Q

What is criteria for RBBB? What are associated features?

A

Diagnostic Criteria

  1. Broad QRS > 120 ms
  2. RSR’ pattern in V1-3 (‘M-shaped’ QRS complex)
  3. Wide, slurred S wave in the lateral leads (I, aVL, V5-6)

‘MaRRoW’ (V1, V6)

Associated Features: ST depression and T wave inversion in the right precordial leads (V1-3)

Variations: Sometimes rather than an RSR’ pattern in V1, there may be a broad monophasic R wave or a qR complex.

22
Q

What is an incomplete RBBB?

A

Incomplete RBBB is defined as an RSR’ pattern in V1-3 with QRS duration < 120ms.
It is a normal variant, commonly seen in children (of no clinical significance).

23
Q

What are causes for RBBB? (3)

A
  1. Right ventricular hypertrophy / cor pulmonale
  2. Pulmonary embolus
  3. Ischaemic heart disease
  4. Rheumatic heart disease
  5. Myocarditis or cardiomyopathy
  6. Degenerative disease of the conduction system
  7. Congenital heart disease (e.g. atrial septal defect)
24
Q

What is the criteria for LBBB? (3) What are associated features (3)

A

Diagnostic Criteria

‘WiLLiaM’ V1, V6

  1. QRS duration of 120 ms
  2. Dominant S wave in V1
  3. Broad monophasic R wave in lateral leads (I, aVL, V5-V6)
  4. Absence of Q waves in lateral leads (I, V5-V6; small Q waves are still allowed in aVL)
  5. Prolonged R wave peak time > 60ms in left precordial leads (V5-6)

Associated Features

  • Appropriate discordance: the ST segments and T waves always go in the opposite direction to the main vector of the QRS complex
  • Poor R wave progression in the chest leads
  • Left axis deviation
25
Q

What are causes of LBBB? (5)

A
  1. Anterior MI
  2. Ischaemic heart disease
  3. Aortic stenosis
  4. Hyperkalaemia
  5. Digoxin toxicity
  6. Hypertension
  7. Dilated cardiomyopathy
  8. Primary degenerative disease (fibrosis) of the conducting system (Lenegre disease)
26
Q

DDX ST Depression

A
  1. Myocardial ischaemia / NSTEMI
  2. Reciprocal change in STEMI
  3. Posterior MI
  4. Digoxin effect
  5. Hypokalaemia
  6. Supraventricular tachycardia
  7. Right bundle branch block
  8. Right ventricular hypertrophy
  9. Left bundle branch block
  10. Left ventricular hypertrophy
  11. Ventricular paced rhythm
27
Q

STE in II, III, aVF, what vessel is involved?

A

RCA or LCx (less common)

28
Q

STE in V1-V4 what vessel is involved?

A

LAD

29
Q

STE in I, aVL, V5, V6 what vessel is involved?

A

LCx or diagonal branch of LAD

30
Q

ddx R>S in V2

A 
True Posterior infarct *
RBBB
WPW
Pediatric patient
RVH
Ventricular septal hypertrophy
31
Q

What criteria is for pathological Q waves?

A

> 40 ms
Size >25% QRS
Present in >2 contiguous leads

32
Q

DDX LAD (4)

A

Left ventricular hypertrophy
Left bundle branch block
Inferior MI
Ventricular pacing /ectopy
Wolff-Parkinson-White Syndrome
Left anterior fascicular block – diagnosis of exclusion
Horizontally orientated heart – short, squat patient

33
Q

DDX New RBBB thats life threatening (4)

A

Na Channel blockers OD
PE
Ischemia
Hyperkalemia

34
Q

DDX inverted T waves (5)

A 
Normal finding in children
Persistent juvenile T wave pattern (after age 8)?
Myocardial ischaemia (PE) and infarction
Bundle branch block
Ventricular hypertrophy (‘strain’ patterns)
Pulmonary embolism
Hypertrophic cardiomyopathy
Raised intracranial pressure
35
Q

DDX VT (4)

A
  1. ACS
  2. Scarring (old infarct)
  3. Electrolytes (K, Ca (low), Mg)
  4. Hypoxia
36
Q

What 3 findings on avR is suspect for TCA or sodium channel toxicity?

A
  1. QRS >100 ms (assoc with sz), QRS >160 ms (assc with ventricular dysrythmias)
  2. RAD
    a) Terminal R wave >3 mm aVR
    b) R/S ratio >0.7 in aVR
37
Q

What is a capture beat?

A

When the sinoatrial node transiently captures the ventricles and a narrow complex beat shows on ecg.

38
Q

What is the Ddx of WCT on ecg? (3)

A
  1. VT
  2. SVT with aberrancy due to BBB
  3. SVT with aberrancy due to WPW accessory pathway
  4. Hyperkalemia
39
Q

In pt with WCT what features make VT more likely? (5)

A
  1. Absence of typical RBBB or LBBB morphology
  2. Extreme axis deviation (“northwest axis”) — QRS is positive in aVR and negative in I + aVF.
  3. Very broad complexes (>160ms)
  4. AV dissociation (P and QRS complexes at different rates) - most useful.
    - capture beats and fusion beats are a sign of this..
  5. Capture beats — occur when the sinoatrial node transiently ‘captures’ the ventricles, in the midst of AV dissociation, to produce a QRS complex of normal duration.
  6. Fusion beats — occur when a sinus and ventricular beat coincides to produce a hybrid complex.
  7. Positive or negative concordance throughout the chest leads, i.e. leads V1-6 show entirely positive (R) or entirely negative (QS) complexes, with no RS complexes seen.
  8. Brugada’s sign – The distance from the onset of the QRS complex to the nadir of the S-wave is > 100ms
  9. Josephson’s sign – Notching near the nadir of the S-wave
  10. RSR’ complexes with a taller left rabbit ear. This is the most specific finding in favour of VT. This is in contrast to RBBB, where the right rabbit ear is taller.
40
Q

What is a fusion beat?

A

Occurs when a sinus beat and a ventricle beat occur as the same time and you get a hybrid complex (is more wide qrs compared to capture beat)

41
Q

What should you worry about if you see an ECG that has normal T-waves and on previous old ones they are inverted?

A

Pseudo-normalization.

This is an indication of ischemia.

42
Q

What are causes of STE? (17)

A
  1. MI
  2. Ao dissection
  3. Ventricular aneurysm
  4. LVH
  5. Brugada
  6. Pericarditis/myocarditis
  7. Benign early repolarizatin
  8. Prizmental’s angina
  9. PE
  10. Hyperkalemia
  11. LBBB
  12. Ventricular paced rhythm
  13. Raised ICP/intra-cranial hemorrhage.
  14. Post cardioversion
  15. Taksubo’s cardiomyopathy
  16. Hypothermia - Osborn J waves
  17. Normal variant.
43
Q

DDX irregularly irregular rhythm on ecg? (5)

A
  1. Afib
  2. AFlutter with variable conduction
  3. MAT
  4. Wandering pacemaker
  5. Multiple extrasystoles
44
Q

An adult has Afib with a rate >200. What do they likely have?

A

An accessory pathway

45
Q

Explain what the Ashmann phenomenon is

A

Ashmann phenomenon is when after a long R-R interval the early arriving atrial impulse is aberrently conducted through the venticular system due to a partially refractory His Bundle.
It is commonly mistaken for VT.
Occurs in patients with Afib.

46
Q

DDx slow AFib (4)

A

Digoxin toxicity
BB/CCB
Severe AV nodal disease
Hypothermia

47
Q

What are 7 ecg changes in hypothermia?

A
  1. Bradyarrhythmias
    - sinus brady
    - Afib with slow ventricular response
    - Slow junctional rhythms
    - AVB’s
  2. Osborne Waves (= J waves)
  3. Prolonged PR, QRS and QT intervals
  4. Shivering artefact
  5. Ventricular ectopics
  6. Cardiac arrest due to VT, VF or asystole

Emergency Medicine (39 decks)

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