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


Narrow-complex regular rhythm:

Narrow-complex irregular rhythm:

Wide-complex regular rhythm:

Wide-complex irregular rhythm:

Leftward axis

Low voltage

Increased QRS Duration

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)

Prominent R-wave in lead V1 (R/S ratio >1)

Prominent T-wave

Rightward axis

ST-segment elevation

Important causes of ST elevation

ST segment elevation in V1

Diffuse ST-segment elevation

Advanced Reading

Further reading



LITFL Further Reading


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.

| INTENSIVE | RAGE | Resuscitology | SMACC

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