ECG Differential Diagnosis

Lists of differential diagnoses of specific ECG findings based on from ECGs for the Emergency Physician 1 and ECGs for the Emergency Physician 2

Atrial fibrillation with slow ventricular response

Severe AV nodal disease
Hypothermia
Medications: Digoxin toxicity, Calcium-channel blocker / beta-blocker toxicity

Tachydysrhythmias

Narrow-complex regular rhythm:

Narrow-complex irregular rhythm:

Wide-complex regular rhythm:

Ventricular tachycardia
Sinus tachycardia with aberrant conduction
SVT with aberrant conduction
Atrial flutter with aberrant conduction

Wide-complex irregular rhythm:

Atrial fibrillation with aberrant conduction (for example bundle branch block)
Atrial flutter with variable block and aberrant conduction
Multifocal atrial tachycardia with aberrant conduction
Atrial fibrillation with WPW
Polymorphic ventricular tachycardia / Torsades de Pointes

Leftward axis

Low voltage

Myxoedema
Large pericardial effusion
Large pleural effusion
End-stage dilated cardiomyopathy
Severe chronic obstructive pulmonary disease
Severe obesity
Infiltrative myocardial diseases (i.e. restrictive cardiomyopathy)
Constrictive pericarditis
Prior massive MI
Low gain settings on ECG machine

Increased QRS Duration

Hypothermia
Hyperkalaemia
WPW
Aberrant intraventricular conduction (for example bundle branch block)
Ventricular ectopy
Paced beats
Drugs, particularly those with sodium-channel blocking effects

Increased QT-interval (and QTc-interval)

*Hypokalemia — the actual QT-interval is normal; the QT-interval appears prolonged because of the presence of fusion of the T-wave with a U-wave (a “T-U fusion complex”)

Poor R-wave progression (PRWP)

Prior anteroseptal MI
LVH
Abnormally high placement of the mid-precordial electrodes
Normal variant

ST-segment elevation

Important causes of ST elevation

Acute myocardial infarction (AMI)
Coronary vasospasm (Printzmetal’s angina)
Pericarditis and myocarditis
Benign early repolarisation (BER)
Left bundle branch block (LBBB)
Left ventricular hypertrophy (LVH)
Ventricular aneurysm
Brugada syndrome
Ventricular paced rhythm
Raised intracranial pressure (ICP)

ST segment elevation in V1

Diffuse ST-segment elevation

Advanced Reading

LITFL Further Reading

ECG Library Basics – Waves, Intervals, Segments and Clinical Interpretation
ECG A to Z by diagnosis – ECG interpretation in clinical context
ECG Exigency and Cardiovascular Curveball – ECG Clinical Cases
100 ECG Quiz – Self-assessment tool for examination practice
ECG Reference SITES and BOOKS – the best of the rest

ECG LIBRARY

more EKG…

Chris Nickson

Chris is an Intensivist and ECMO specialist at the Alfred ICU in Melbourne. He is also a 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 three amazing children.

On Twitter, he is @precordialthump.

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