Answer to ECG Quiz no. 28

  • A. Okreglicki Cardiac Clinic, University of Cape Town / Groote Schuur Hospital Cardiac Arrhythmia Society of Southern Africa (CASSA)


Wide QRS complexes are the result of conduction abnormalities or arise in the ventricles. Conduction abnormalities causing wide QRS may be due to conduction system disorders affecting the bundles, accessory pathways or drugs. Confirmation of bundle branch block requires evidence of rapid conduction of the unaffected bundle. Wide non-conducted QRS complexes are either intrinsic (ventricular escape, accelerated idioventricular rhythm or ventricular tachycardia, as classified by rate) or extrinsic (pacing). Accelerated idioventricular rhythm is usually transient and the result of an acute process: infarction, inflammation or injury (surgery).
ECG Quiz