Lists of differential diagnoses of specific ECG findings (from ECGs for the Emergency Physician 1 and 2). Follow the links to read more about each condition.
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:
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
Diffuse ST-segment elevation
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
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)
- Hypokalaemia*
- Hypomagnesaemia
- Hypocalcaemia
- Acute myocardial ischemia
- Elevated intracranial pressure
- Sodium-channel blockers
- Hypothermia
- Congenital prolonged QT syndrome
*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
Prominent R-wave in lead V1 (R/S ratio >1)
- WPW
- Posterior MI
- RBBB (or incomplete RBBB)
- Ventricular ectopy
- RVH
- Acute right ventricular dilatation (right ventricular “strain,” e.g. massive PE)
- Hypertrophic cardiomyopathy
- Progressive muscular dystrophy
- Dextrocardia
- Misplaced precordial electrodes
- Paediatric ECG
- Normal variant (rare)
Prominent T-wave
- Acute myocardial ischemia (i.e. hyperacute STEMI)
- Hyperkalaemia
- Acute pericarditis
- LVH
- Benign early repolarization
- Bundle branch block (LBBB / RBBB)
- Preexcitation syndromes
Rightward axis
- Left posterior fascicular block
- Lateral myocardial infarction
- Right ventricular hypertrophy
- Acute lung disease (e.g. PE)
- Chronic lung disease (e.g. COPD)
- Ventricular ectopy
- Hyperkalaemia
- Sodium-channel blocker toxicity
- Normal in children or thin adults with a horizontally positioned heart
ST-segment elevation in lead V1
Further Reading
- ECG BASICS – Waves, Intervals, Segments and Clinical Interpretation
- ECG CLINICAL CASES – Your favourite ECG’s placed in clinical context with a challenging Q&A approach
- ECG and Cardiology Eponymous Syndromes – Cheats guide to eponymous emancipation
- ECG Reference Sites on the WEB – the best of the rest
Author Credits
References
- Mattu A, Brady W. ECGs for the Emergency Physician 1, BMJ Books 2003.
- Mattu A, Brady W. ECGs for the Emergency Physician 2, BMJ Books 2008.
About Chris Nickson
