Interventricular Conduction Delay (QRS widening)

Definition

  • 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 hyperkalaemia and tricyclic antidepressant poisoning.

Causes

Follow the links to read more about each condition.

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

 

Further Reading

Author Credits

References

  • Chan TC, Brady WJ, Harrigan RA, Ornato JP, Rosen P. ECG in Emergency Medicine and Acute Care. Elsevier Mosby 2005.
  • Edhouse J, Thakur RK, Khalil JM. ABC of clinical electrocardiography. Conditions affecting the left side of the heart. BMJ. 2002 May 25;324(7348):1264-7. Review. PubMed PMID: 12028984; PubMed Central PMCID: PMC1123219 [Print Friendly