Electrocardiogram Interpretation: A Brief Overview

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Electrocardiogram Interpretation A Brief Overview
Wissam Alajaji, MD
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• Objectives
• Basic principles for ECG interpretation
• Normal ECG
• Abnormal ECG examples

13 slides
Know that This presentation will not cover ECG
dilemmas Should you code Q wave in V1, V2 or
only when it involves all V1, V2, V3. A only
when V3 is involved in LBBB should you code
acute MI? A No
Wissam Alajaji, Electrocardiogram Interpretation
A Brief Overview, July-21, 2015.
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Wissam Alajaji, Electrocardiogram Interpretation
A Brief Overview, July-21, 2015.
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Basic principles for ECG interpretation

• Before you look at the ECG
• Indication

- 20 YO man with syncope - 50 YO man with acute
chest pain - 65 YO woman with HTN and chronic
SOB - 70 YO man with ESRD medications include
digoxin, coming with altered level of
consciousness
- Muscle thickness, QT, arrhythmia - Chamber size
and its complications - ischemia and its
complications - electrolytes, drug toxicity
Wissam Alajaji, Electrocardiogram Interpretation
A Brief Overview, July-21, 2015.
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Basic principles for ECG interpretation

• Screen the ECG for quality
• Verify patients name, MRN, and date
• Make sure that voltage is 10 mm/mv and calibrated
• Screen for quality, correct lead placement, noise

Wissam Alajaji, Electrocardiogram Interpretation
A Brief Overview, July-21, 2015.
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Wissam Alajaji, Electrocardiogram Interpretation
A Brief Overview, July-21, 2015.
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Na, TCA
Nothing is Random in Life
K Disturbance
Ca Disturbance, Digoxin
Wissam Alajaji, Electrocardiogram Interpretation
A Brief Overview, July-21, 2015.
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Basic principles for ECG interpretation

• Know how to calculate the HR, PR, QRS, and QT
• Know what is a normal sinus morphology and
  identify abnormal
• Know what is normal axis, normal voltage, normal
  vs pathologic Q, juvenile patterns, normal
  variants

Wissam Alajaji, Electrocardiogram Interpretation
A Brief Overview, July-21, 2015.
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Nomenclature
Waves -P wave -T wave -U wave Complex
-QRS Segments -PR segment -ST
segment Intervals -PR interval -QT
interval Point -J point

• 1 little box 0.04 seconds (or 40 msec)
• 1 big box 0.2 seconds (or 200 msec)
• 5 little boxes 1 big box
• 5 big boxes 1 second

Wissam Alajaji, Electrocardiogram Interpretation
A Brief Overview, July-21, 2015.
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• Step 1
• Locate RR interval HR
• Step 2
• Rhythm its origin
• Can be difficult and complex
• Most common mistake made by computer
  interpretation

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For Boards

• Expected not to miss a serious/deadly
  finding/diagnosis
• ST elevation
• Hyperkalemia
• Drug toxicity
• Major pathology heart block, arrhythmia,
  HCM..
• Usually, your indication is your guide
• Do not worry about controversial or minor findings

Wissam Alajaji, Electrocardiogram Interpretation
A Brief Overview, July-21, 2015.
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ECG Coding Sheet
Wissam Alajaji, Electrocardiogram Interpretation
A Brief Overview, July-21, 2015.
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Wissam Alajaji, Electrocardiogram Interpretation
A Brief Overview, July-21, 2015.
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Abnormally, normal avR
Unexpectedly "normal"
Inverted lead I in absence of Dextrocardia
Wissam Alajaji, Electrocardiogram Interpretation
A Brief Overview, July-21, 2015.
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Rhythm
Wissam Alajaji, Electrocardiogram Interpretation
A Brief Overview, July-21, 2015.
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• So Far
• You learned to ask about/present the indication
  before interpretation
• Scan for quality and lead placement
• Know the various electrical waves/intervals and
  what is normal ECG

Wissam Alajaji, Electrocardiogram Interpretation
A Brief Overview, July-21, 2015.
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Chamber Abnormality
Wissam Alajaji, Electrocardiogram Interpretation
A Brief Overview, July-21, 2015.
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24 year old man with syncope
Wissam Alajaji, Electrocardiogram Interpretation
A Brief Overview, July-21, 2015.
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45 year old man with HTN
Wissam Alajaji, Electrocardiogram Interpretation
A Brief Overview, July-21, 2015.
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LVH Criteria

• The Cornell criteria
• R wave in aVL S wave in V3 gt 28 mm in males and
  gt 20 mm in females of the voltage criteria.
• Therefore, the best policy is know most or all of
  the
• Sokolow
• S in V1 or 2 R in V5 or V6 gt 35 mV
• R avL gt 11 mV
• ST and/or T wave abnormalities, strain pattern

Wissam Alajaji, Electrocardiogram Interpretation
A Brief Overview, July-21, 2015.
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Wissam Alajaji, Electrocardiogram Interpretation
A Brief Overview, July-21, 2015.
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Codes 07 Sinus rhythm 37 Right axis deviation (gt
100 msec) 41 Right ventricular hypertrophy 43
RBBB, complete 67 ST and/or T wave abnormalities
secondary to hypertrophy
Wissam Alajaji, Electrocardiogram Interpretation
A Brief Overview, July-21, 2015.
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Chest pain/SOB
Wissam Alajaji, Electrocardiogram Interpretation
A Brief Overview, July-21, 2015.
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Wissam Alajaji, Electrocardiogram Interpretation
A Brief Overview, July-21, 2015.
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Codes 10 Sinus tachycardia 43 RBBB, complete 46
Left posterior fascicular block 53 Anterior or
anteroseptal Q wave MI (age recent or acute) 57
Inferior Q wave MI (age recent or acute) 65 ST
and/or T wave abnormalities suggesting myocardial
injury
Wissam Alajaji, Electrocardiogram Interpretation
A Brief Overview, July-21, 2015.
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• Q1
• Significant ST segment elevation consistent with
  myocardial injury or infarction is defined by
• 1 mm STE in leads V1, V2, or V3
• 2 mm STE in leads V1, V2, or V3
• 2 in other leads
• 1 in other leads

Wissam Alajaji, Electrocardiogram Interpretation
A Brief Overview, July-21, 2015.
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• Q1
• Significant ST segment elevation consistent with
  myocardial injury or infarction is defined by
• 1 mm STE in leads V1, V2, or V3
• 2 mm STE in leads V1, V2, or V3
• 2 in other leads
• 1 in other leads

Wissam Alajaji, Electrocardiogram Interpretation
A Brief Overview, July-21, 2015.
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• Q2
• Repolarization abnormality that suggest Acute or
  recent Myocardial infarction include
• Peaked T waves followed by T wave inversion
• ST elevation followed by peaked T waves
• Deeply inverted T waves
• Dominant R wave and ST depression in V1-V3

Wissam Alajaji, Electrocardiogram Interpretation
A Brief Overview, July-21, 2015.
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• Q2
• Repolarization abnormality that suggest Acute or
  recent Myocardial infarction include
• Peaked T waves followed by T wave inversion
• ST elevation followed by peaked T waves
• Deeply inverted T waves
• Dominant R wave and ST depression in V1-V3

Wissam Alajaji, Electrocardiogram Interpretation
A Brief Overview, July-21, 2015.
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• Q3
• Which parameter obtained on initial ECG
  independently predict 30 day all-cause mortality
  in acute myocardial infarction
• Sinus tachycardia
• Sum of absolute ST segment deviation elevation
  and or depression
• QRS duration gt 100 msec
• Rightward axis deviation

Wissam Alajaji, Electrocardiogram Interpretation
A Brief Overview, July-21, 2015.
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• Q3
• Which parameter obtained on initial ECG
  independently predict 30 day all-cause mortality
  in acute myocardial infarction
• Sinus tachycardia
• Sum of absolute ST segment deviation elevation
  and or depression
• QRS duration gt 100 msec
• Rightward axis deviation

Hathaway WR, et al. JAMA 1996, 273 387-391.
Wissam Alajaji, Electrocardiogram Interpretation
A Brief Overview, July-21, 2015.
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Wissam Alajaji, Electrocardiogram Interpretation
A Brief Overview, July-21, 2015.
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Wissam Alajaji, Electrocardiogram Interpretation
A Brief Overview, July-21, 2015.
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Wissam Alajaji, Electrocardiogram Interpretation
A Brief Overview, July-21, 2015.
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Codes 06 Left atrial abnormality/enlargement 10
Sinus tachycardia 36 Left axis deviation (gt
30o) 47 LBBB, complete
Wissam Alajaji, Electrocardiogram Interpretation
A Brief Overview, July-21, 2015.
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• Q1
• A QRS duration seconds is necessary for the
  diagnosis of complete LBBB
• 0.10
• 0.11
• 0.12
• 0.13

Wissam Alajaji, Electrocardiogram Interpretation
A Brief Overview, July-21, 2015.
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• Q1
• A QRS duration seconds is necessary for the
  diagnosis of complete LBBB
• 0.10
• 0.11
• 0.12
• 0.13

When LBBB morphology is present and the QRS
duration measures gt 0.10 seconds but lt 0.12
seconds, incomplete LBBB should be coded.
Wissam Alajaji, Electrocardiogram Interpretation
A Brief Overview, July-21, 2015.
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• Q2
• LBBB is commonly seen in normal hearts
• True
• False

Wissam Alajaji, Electrocardiogram Interpretation
A Brief Overview, July-21, 2015.
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• Q2
• LBBB is commonly seen in normal hearts
• True
• False

Never normal finding LBBB often occurs in various
forms of organic heart disease, including
ischemic and non-ischemic cardiomyopathy,
valvular heart disease, LVH, and congenital heart
disease. It is rarely seen in normal
hearts Should not call it STEMI Should not call
LVH 80 patients with LBBB have abnormally
increased LV mass
Wissam Alajaji, Electrocardiogram Interpretation
A Brief Overview, July-21, 2015.
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• Q3
• Non-voltage related changes often associated with
  left ventricular hypertrophy include all the
  following except
• Left atrial enlargement/abnormality
• Left axis deviation
• Intraventricular conduction disturbance
• Prominent U waves
• Sinus arrhythmia

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• Q3
• Non-voltage related changes often associated with
  left ventricular hypertrophy include all the
  following except
• Left atrial enlargement/abnormality
• Left axis deviation
• Intraventricular conduction disturbance
• Prominent U waves
• Sinus arrhythmia

Non-voltage ECG changes in LVH LA
abnormality/enlargement, left axis, IVCD, QRS
prolongation, abnormal Q waves in leads III and
aVF, prominent U waves, and repolarization
abnormalities. Sinus arrhythmia (longest and
shortest PP intervals vary by gt 0.16 seconds or
10) is a common finding on normal ECGs that
tends to occur in younger and healthier
individuals and is not associated with LVH
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• Q4
• LBBB interferes with the ECG diagnosis of
• QRS axis
• Left ventricular hypertrophy
• Right ventricular hypertrophy
• Acute MI

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• Q4
• LBBB interferes with the ECG diagnosis of
• QRS axis
• Left ventricular hypertrophy
• Right ventricular hypertrophy
• Acute MI

Formal diagnosis of LVH should not be made in the
setting LBBB Echocardiographic and pathological
studies show that 80 patients with LBBB have
abnormally increased LV mass
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Bradycardia

• A very big book in ECG
• Just on fun example

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Wissam Alajaji, Electrocardiogram Interpretation
A Brief Overview, July-21, 2015.
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Codes 07 Sinus rhythm 13 Atrial premature
complexes
Wissam Alajaji, Electrocardiogram Interpretation
A Brief Overview, July-21, 2015.
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Tachycardia
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Wissam Alajaji, Electrocardiogram Interpretation
A Brief Overview, July-21, 2015.
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Codes Sinus tachycardia Paroxysmal SVT
Wissam Alajaji, Electrocardiogram Interpretation
A Brief Overview, July-21, 2015.
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Killer
Wissam Alajaji, Electrocardiogram Interpretation
A Brief Overview, July-21, 2015.
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24 year old man with stressful life
Wissam Alajaji, Electrocardiogram Interpretation
A Brief Overview, July-21, 2015.
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Electrolyte/Drug toxicity
Wissam Alajaji, Electrocardiogram Interpretation
A Brief Overview, July-21, 2015.
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65 year old man ESRD on dialysis presented with
acute confusion
Peaked T waves
Wissam Alajaji, Electrocardiogram Interpretation
A Brief Overview, July-21, 2015.
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17 year old female found by her room mate
unconscious
Wissam Alajaji, Electrocardiogram Interpretation
A Brief Overview, July-21, 2015.