Definition of QRS widening
Causes of Interventricular Conduction Delay
Fascicular and bundle-branch blocks
- Left anterior fascicular block
- Left posterior fascicular block
- Left bundle branch block
- Right bundle branch block
- Bifascicular block
- Trifascicular block
Ventricular hypertrophy and dilatation
- Left ventricular hypertrophy
- Right ventricular hypertrophy
- Biventricular enlargement
- Dilated cardiomyopathy
- Sodium-channel blocker toxicity (e.g. TCA overdose) – wide QRS plus positive R’ wave in aVR.
Arrhythmogenic cardiac conditions
- Brugada syndrome – localised QRS widening in V1-2 with RBBB morphology.
- Arrhythmogenic right ventricular dysplasia (AVRD) – localised QRS widening in V1-2 plus epsilon waves and variable signs of right ventricular hypertrophy.
- Not due to any of the causes above — Before making this diagnosis, be sure to check the serum potassium level and scrutinise the ECG for any signs of TCA toxicity.
- Brady WJ, Truwit JD. Critical Decisions in Emergency and Acute Care Electrocardiography
- Hampton, JR. The ECG In Practice, 6e
- Surawicz B, Knilans T. Chou’s Electrocardiography in Clinical Practice: Adult and Pediatric, 6e
- Wagner, GS. Marriott’s Practical Electrocardiography 12e
- Chan, TC. ECG in Emergency Medicine and Acute Care
- Mattu, A. ECG’s for the Emergency Physician
LITFL Further Reading
- ECG BASICS — Waves, Intervals, Segments and Clinical Interpretation
- ECG A to Z by diagnosis –alphabetical diagnostic approach to the ECG
- ECG CLINICAL CASES — ECG’s placed in clinical context with a challenging Q&A approach
- 100 ECG Quiz — Self-assessment tool for examination practice
- ECG Reference SITES and BOOKS — the best of the rest
- LITFL ECG IMAGE Database — Searchable database of LITFL ECG’s
- ECG and Cardiology Eponymous Syndromes — Cheats guide to eponymous emancipation
- ECG Exam Template — a framework for answering ECG exam questions.