Definition of QRS widening
QRS duration > 100 ms in the presence of a supraventricular rhythm. Most commonly due to bundle branch block or left ventricular hypertrophy.
The most important life-threatening causes of QRS widening are:
Causes of Intraventricular Conduction Delay
Fascicular and bundle-branch blocks
Ventricular hypertrophy and dilatation
Electrolyte abnormalities
Toxins
Pre-excitation
Arrhythmogenic cardiac conditions
“Non-specific” IVCD
- 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.
Differential Diagnosis
Ventricular Rhythms
References
Advanced Reading
Online
Textbooks
- Zimmerman FH. ECG Core Curriculum. 2023
- Mattu A, Berberian J, Brady WJ. Emergency ECGs: Case-Based Review and Interpretations, 2022
- Straus DG, Schocken DD. Marriott’s Practical Electrocardiography 13e, 2021
- Brady WJ, Lipinski MJ et al. Electrocardiogram in Clinical Medicine. 1e, 2020
- Mattu A, Tabas JA, Brady WJ. Electrocardiography in Emergency, Acute, and Critical Care. 2e, 2019
- Hampton J, Adlam D. The ECG Made Practical 7e, 2019
- Kühn P, Lang C, Wiesbauer F. ECG Mastery: The Simplest Way to Learn the ECG. 2015
- Grauer K. ECG Pocket Brain (Expanded) 6e, 2014
- Surawicz B, Knilans T. Chou’s Electrocardiography in Clinical Practice: Adult and Pediatric 6e, 2008
- Chan TC. ECG in Emergency Medicine and Acute Care 1e, 2004
LITFL Further Reading
Emergency Physician in Prehospital and Retrieval Medicine in Sydney, Australia. He has a passion for ECG interpretation and medical education | ECG Library |
MBBS DDU (Emergency) CCPU. Adult/Paediatric Emergency Medicine Advanced Trainee in Melbourne, Australia. Special interests in diagnostic and procedural ultrasound, medical education, and ECG interpretation. Co-creator of the LITFL ECG Library. Twitter: @rob_buttner