ECG STAMPEDE

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An Adaptation of the ECG Stampede Curriculum

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By Ronnie Rivera, M.D.

Learning Objectives:

1. Learn a stepwise approach to evaluating the ECG in front of you
2. Understand important ECG morphologies and their significance
3. Introduce you to presentations of ischemia
4. Introduce you to ischemia mimics

CASE #1:

39 yo female presenting with chest pain

What is your approach to interpreting this ECG?

Standardize your approach

1. Rate
2. Rhythm
3. Axis
4. Intervals
5. Morphologies

Rate

How Long is an ECG?

Trick for Determining Rate at a Glance:

Rhythm

Approach to Rhythm:

1. Rate
2. P-Waves
3. P & QRS Relationship
4. QRS Pattern
5. QRS Length

Rate: Fast or Slow?

1. Tachycardia > 100

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1. Bradycardia <60

P-waves: Present or Absent?

1. Sinus Rhythm

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1. Atrial Fibrillation

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1. Atrial Flutter

Forms of Atrial Flutter:

P to QRS Relationship

1. First Degree AV Block
2. Second Degree AV Block
1. Mobitz Type 1
2. Mobitz Type 2
3. Third Degree AV Block

QRS Length:

1. Supraventricular Tachycardia (Narrow)

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1. Ventricular Tachycardia (Wide)
1. Monomorphic
2. Polymorphic
3. Torsades de Pointes

Axis

Electrical Conduction in the Heart

What Does This Mean With Our Leads?

We Do Not Have: RA, LA, and LL!

Einthoven’s Triangle

I

II

III

AVR

AVL

AVF

How We Get ECG Leads!

What Do Leads Have To Do With Axis?

What Do Leads Have To Do With Axis?

What Do Leads Have To Do With Axis?

What Do Leads Have To Do With Axis?

What Do Leads Have To Do With Axis?

What Do Leads Have To Do With Axis?

Finding the Axes

Positive deflection

Negative deflection

Equiphasic deflection

Trying it out:

Axis Trick:

What Causes Axis Deviation?

Right Axis Deviation

• Right ventricular hypertrophy
• Acute right ventricular strain, e.g. due to pulmonary embolism
• Lateral STEMI
• Chronic lung disease, e.g. COPD
• Hyperkalaemia
• Sodium-channel blockade, e.g. TCA poisoning
• Wolff-Parkinson-White syndrome
• Dextrocardia
• Ventricular ectopy
• Secundum ASD – rSR’ pattern
• Normal paediatric ECG
• Left posterior fascicular block – diagnosis of exclusion
• Vertically orientated heart – tall, thin patient

Left Axis Deviation

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

Intervals

Intervals:

Memorize:

PR: 120-200ms

QRS: <120ms

QT: 350-500ms

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Important Takeaway Points:

1. Rate
2. Rhythm
3. Axis
4. Intervals
5. Morphologies

Morphologies / Ischemia

CASE #2:

21yo male presents with AMS after MVC

J-point Notching:

Known as a fish hook morphology.

Not always seen in every lead.

Most prominent in V4

Important Takeaway Points:

1. Diffuse ST segment elevation is an important morphology to notice
2. Pay attention for reciprocal changes to decide STEMI vs other causes
3. Early repolarization pattern can be characterized with J-point notching.

CASE #3:

50yo male presents with chest pain

Leads V1 through V3

Leads II, III, and AVF

ECG Anatomical Distributions

Additional Questions:

What are the critical actions you should take with this patient?

1. IV/O2/monitor/defibrillation pads,
2. Nitroglycerin*, aspirin, +/- P2Y12 inhibitors,
3. +/- heparin gtt,
4. Thrombolytics or transfer > 120 min anticipated

Important Takeaway Points:

1. ST Segment elevation is an important morphology to recognize.
2. Look for reciprocal changes
3. Understand the anatomical distributions of the ECG with the vessels of the heart

CASE #4:

73yo female with chest pain

Morphologies Specific to RBBB

Causes of RBBB:

RBBB can be caused by:

1. right ventricular hypertrophy
2. cor pulmonale,
3. pulmonary embolism,
4. ischemic heart disease,
5. rheumatic heart disease,
6. myocarditis or cardiomyopathy,
7. degenerative disease of the conduction system
8. congenital heart disease (e.g. atrial septal defect).

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Important Takeaway Points:

1. T wave inversions can be associated with cardiac ischemia or RBBB
2. The morphology in V1 will be different than the morphology in V6
3. A new RBBB may need to be investigated for significant causes like Pulmonary Embolism

CASE #5:

77yo male presents with shortness of breath

Morphologies Specific to LBBB

Sgarbossa’s Criteria:

Original Criteria

Modified Criteria

Both ratios are > 0.25 or 25%

Concordant

Discordant

ST elevation

Discordant

ST depression

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Causes of LBBB:

It is unusual for LBBB to exist in the absence of organic disease. Causes are varied and include:

1. Aortic stenosis
2. Ischaemic heart disease
3. Hypertension
4. Dilated cardiomyopathy
5. Anterior MI
6. Lenègre-Lev disease: primary degenerative disease (fibrosis) of the conducting system
7. Hyperkalaemia
8. Digoxin toxicity

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Important Takeaway Points:

1. ST segment elevation can be seen in cardiac ischemia or LBBB
2. The morphology in V1 will be different than that of V6
3. The QRS will be wide
4. Sgarbossa’s criteria will help to evaluate for STEMI in LBBB

CASE #6:

43yo female presenting with chest pain

Inferior Leads - A closer Look

Anterior Leads: A Closer Look

Lateral Leads: A Closer Look

ECG Anatomical Distributions

Posterior Leads:

1. Posterior leads can be used to tell us about the posterior segment of the heart
2. You can add leads 7-9 that will replace 4-6 on your ECG
3. You can also take V4 and move it to the back where you see V8 (under the point of the scapula) and look for STE in V4

Important Takeaway Points:

1. ST segment elevations are signs of cardiac ischemia
2. ST segment depressions can be signs of cardiac ischemia
3. Reciprocal changes can help to determine cardiac ischemia
4. If reciprocal changes or ST elevation do not match an anatomical distribution, there may be multiple areas / vessels involved.

CASE #7:

69yo male presenting with AMS (EMS note)

ST segment elevations

ST segment reciprocal depressions?

Other important morphology:

T waves on our ECG

Are ours the same as these hyperacute T waves?

Repeat ECG after calcium administration

And after even more calcium

Important Takeaway Points:

1. ST segment elevations can be paired reciprocal changes and still not represent a STEMI
2. Look at the patient and their history to determine what might be happening
3. Be sure to look for other morphologies that might clue you in to what is happening
4. Repeat ECG’s can help to see if there are dynamic changes with treatment

CASE #8:

80yo female presents with typical chest pain

AVR - A closer look

Anterolateral ST segment depressions

More ST segment depressions

ECG Anatomical Distributions

Important Takeaway Points:

1. ST segment elevations in AVR are concerning for severe disease
2. If ST segment elevations are found in AVR, look at the patient’s symptoms
3. Do not miss ischemia by ignoring AVR.

Summary:

1. Use a stepwise approach to evaluating the ECG in front of you
1. Rate, rhythm, axis, intervals, morphologies
2. ST segment elevations and depressions are signs of ischemia, except for when they are not, but don’t mess around.
3. Think about what else might be going on with your patient’s symptoms and findings
4. Get the patient somewhere to get evaluated ASAP!

END

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References:

1. www.ecgstampede.com
2. https://litfl.com/ecg-rate-interpretation/
3. https://litfl.com/ecg-axis-interpretation/