ECG Exam Template

The following headings and prompts can be used as template for ECG-based exam questions.

ECG type and recording

  • 12 lead vs rhythm strip, rate (normal 25 mm/s)
  • Calibration (5mm wide, 10mm high = 1mV)
  • Unusual leads – right, posterior, lead grouping format

Rate

  • normal 60 – 100/min
  • tachy/bradycardia (SA node) vs –arrhythmia (not SA node)
  • method: 300/RR interval (large squares) or number of QRS complexes x 6 (if 25mm/s)

ECG RATE rhythm strip 10 seconds 300 1500 rules ECG

Rhythm

  • Pattern – regular/ regularly irregular/ irregularly irregular
  • Seven step approach to rhythm analysis

Axis

  • Normal QRS axis -30 to 90/ LADRAD/ NW axis
  • Rotation (clockwise/ anticlockwise)

Axis Methods:

  • Quick look test (Lead I and aVF)
  • Three Lead Analysis (Lead I, Lead IIaVF)
  • Isoelectric Lead Analysis
  • Super SAM the axis Man

P wave

  • Present? (esp check II and V1)
  • Amplitude + duration: normal <3mm high and wide (LAE/RAE/Biatrial)
  • Contour: normal — inverted aVR, biphasic V1, upright I,II, aVF, V2-V6

PR interval + PR segment


Q wave

  • Normal: <25%R in I, aVL, AVF, V456
  • Pathological: V23 > 0.02s, other >0.03s + >1mm deep

R wave


QRS complex

  • Duration: 60-110msec normal/ wide; R wave peak time
  • Amplitude: normal/ large voltage/ low voltagealternans
  • Morphology: notched/ RBBBLBBB

ST Segment

  • Displacement: elevation/ depression (J point vs TP interval)
  • Contour: horizontal /upsloping / downsloping
ECG J point J wave J point elevation
J point in a) normal; b) c) J point (ST) elevation; d) J point (ST) depression; e) with J wave (Osborn wave)

ST segment depression upsloping downsloping horizontal

T wave

  • Amplitude: normal <2/3 R/ peaked/ inversion/ alternans

QT Interval

  • Duration: normal 390-450 or 460msec / long/ short/ QT dispersion
  • Method, 3+ QRS in 3+ leads, QTc formulae, caveats

QT interval with u waves maximum T wave slope intersection

U wave

  • Normal 10% T or <1.5mm/ prominent/ inversion/ alternans

Additional waves


Chamber hypertrophy


Lethal – do not miss!


Other tricks and traps


Synthesis

  • Leave space to put this at the start of the answer
  • Unifying diagnosis, DDx, life threats

LITFL Further Reading


Advanced Reading


ECG LIBRARY 700

ECG LIBRARY

Electrocardiogram

Chris is an Intensivist and ECMO specialist at the Alfred ICU in Melbourne. He is also the Innovation Lead for the Australian Centre for Health Innovation at Alfred Health and Clinical Adjunct Associate Professor at Monash University. He is a co-founder of the Australia and New Zealand Clinician Educator Network (ANZCEN) and is the Lead for the ANZCEN Clinician Educator Incubator programme. He is on the Board of Directors for the Intensive Care Foundation and is a First Part Examiner for the College of Intensive Care Medicine. He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives.

After finishing his medical degree at the University of Auckland, he continued post-graduate training in New Zealand as well as Australia’s Northern Territory, Perth and Melbourne. He has completed fellowship training in both intensive care medicine and emergency medicine, as well as post-graduate training in biochemistry, clinical toxicology, clinical epidemiology, and health professional education.

He is actively involved in in using translational simulation to improve patient care and the design of processes and systems at Alfred Health. He coordinates the Alfred ICU’s education and simulation programmes and runs the unit’s education website, INTENSIVE.  He created the ‘Critically Ill Airway’ course and teaches on numerous courses around the world. He is one of the founders of the FOAM movement (Free Open-Access Medical education) and is co-creator of litfl.com, the RAGE podcast, the Resuscitology course, and the SMACC conference.

His one great achievement is being the father of two amazing children.

On Twitter, he is @precordialthump.

| INTENSIVE | RAGE | Resuscitology | SMACC

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