How to read EKGs

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  1. Overview of Dubin’s Method for Reading EKG’s
    1. 1. RATE (pp. 65-96)
    2. 2. RHYTHM (pp. 97-202)
    3. 3. AXIS (pp. 203-242)
    4. 4. HYPERTROPHY (pp. 243-258)
    5. 5. INFARCTION (pp. 259-308)
  2. Further discussion
    1. Rate (pp. 65-96)
    2. Rhythm (pp. 97-111)
    3. Rhythm – continued (pp. 112-172)
    4. Rhythm (Heart Blocks) (pp. 173-202)
    5. Axis (pp. 203-242)
    6. Hypertrophy (pp. 243-258)
    7. Infarction (pp. 259-308)
    8. Infarction Location/Coronary Vessel Involvement
  3. Miscellaneous (pp. 309-328)
  4. Practical Tips

Overview of Dubin’s Method for Reading EKG’s

1. RATE (pp. 65-96)

Estimate using “300, 150, 100…”

Bradycardia: rate = cycles/6 sec. strip × 10

2. RHYTHM (pp. 97-202)

Identify basic rhythm, scan for prematurity, pauses, irregularity, abnormal waves. Check for:

  • P before each QRS, QRS after each P
  • PR intervals (AV Blocks)
  • QRS interval (BBB)
  • If Axis Deviation, rule out Hemiblock.

3. AXIS (pp. 203-242)

QRS above or below baseline for Axis Quadrant (Normal vs. R. or L. Axis Deviation).

Find isoelectric QRS in a limb lead for Axis in degrees using the “Axis in Degrees” chart.

Axis rotation (horizontal plane): find “transitional” (isoelectric) QRS.

4. HYPERTROPHY (pp. 243-258)

Check P wave (atrial hypertrophy).

Check R wave in V₁ (Right Ventricular Hypertrophy).

Check S wave depth in V₁ and R wave height in V (Left Ventricular Hypertrophy).

5. INFARCTION (pp. 259-308)

Scan leads for:

Q waves

Inverted T waves

ST segment elevation/depression

Find location of pathology and identify the occluded coronary artery.

Further discussion

Rate (pp. 65-96)

Determine rate by observation using the triplet method (300-50).

Fine division/rate association reference chart provided.

  • Bradycardia: cycles/6 second strip × 10 = rate
  • Sinus Rhythm: SA Node origin; normal rate 60-100/min.

100/min = Sinus Tachycardia

<60/min = Sinus Bradycardia

Determine independent (atrial/ventricular) rates if co-existing rhythms are present

  • Dissociated Rhythms: sinus or atrial rhythm can co-exist with an independent rhythm from a focus of a lower level
  • Irregular Rhythms: note average ventricular rate (QRS’s/6-sec strip x 10)

Rhythm (pp. 97-111)

Identify basic rhythm, then scan tracing for pauses, premature beats, irregularity, and abnormal waves.

Always check: P before each QRS, QRS after each P; PR intervals, QRS interval; QRS vector shift outside normal range

  • Irregular Rhythms:
  • Sinus Arrhythmia: Irregular, varies with respiration, all P waves identical
  • Wandering Pacemaker: Irregular, P waves change shape, rate < 100/minute
  • Multifocal Atrial Tachycardia: Rate >100/min; otherwise similar to Wandering Pacemaker
  • Atrial Fibrillation: Irregular ventricular rhythm, no P waves (erratic atrial spikes)

Rhythm – continued (pp. 112-172)

  • Escape (pp. 112-121) – The heart’s response to a pause in pacing.

An unhealthy Sinus (SA) Node fails to emit a pacing stimulus (“Sinus Block”).

A sick Sinus (SA) Node may cease pacing (“Sinus Arrest”).

Escape Beats can be: Atrial, Junctional, or Ventricular.

  • Premature Beats (pp. 122-145) – From an irritable automaticity focus.

Premature Beats can be: Atrial, Junctional, or Ventricular.

  • Tachyarrhythmias (pp. 146-172)

Paroxysmal – rate: 150-250/min.

Flutter – rate 250-350/min

Fibrillation – rate 350-450/min

Rhythm (Heart Blocks) (pp. 173-202)

  • Sinus (SA) Block: An unhealthy sinus node misses one or more cycles; The SA Node usually resumes pacing, but the pause may evoke an “escape” response from an automaticity focus.
  • AV Block: Blocks that delay or prevent atrial impulses from reaching the ventricles.

1st AV Block: Prolonged PR interval

2nd AV Block: Some P waves without QRS response

Wenckebach

Mobitz

3rd AV Block: No P wave produces a QRS response

Axis (pp. 203-242)

  • General determination – is QRS (+) or (-) in leads I and AVF
  • First determine axis quadrant

if the QRS is positive in I and AVF = Normal

Axis in Degrees

After locating the Axis Quadrant, find the limb lead where QRS is most isoelectric

  • Axis rotation (left/right) in the Horizontal Plane:

Find transitional (isoelectric) QRS in a chest lead

Hypertrophy (pp. 243-258)

  • Atrial Hypertrophy

Right Atrial Hypertrophy: Large, diphasic P wave with tall initial component

Left Atrial Hypertrophy: Large, diphasic P wave with wide terminal component

  • Ventricular Hypertrophy

Right Ventricular Hypertrophy

Left Ventricular Hypertrophy

Infarction (pp. 259-308)

  • Q wave = Necrosis (significant Q’s only)
  • ST segment elevation = (acute) Injury (also Depression)
  • T wave inversion = Ischemia

Always obtain patient’s previous EKG’s for comparison!

Infarction Location/Coronary Vessel Involvement

Know Coronary Artery Anatomy.

Posterior

Lateral

Inferior

Anterior

Miscellaneous (pp. 309-328)

Pulmonary Embolism

Artificial Pacemakers

Electrolytes:

Potassium

Calcium

Digitalis

Quinidine

Practical Tips

Dubin’s Quickie Conversion: Patient’s weight in kg. = Half of patient’s wt. (in lb.) minus 1/10 of that value.

Modified Leads for Cardiac Monitoring.