ACLS review: Wide Complex Tachycardia (WCT) Part 3

Narrow Complex Tachycardias

·         Atrial fibrillation

·         Atrial flutter

·         AV nodal reentry

·         Accessory pathway–mediated tachycardia

·         Atrial tachycardia (including automatic and reentry forms)

·         Multifocal atrial tachycardia (MAT)

·         Junctional tachycardia (rare in adults)

Note:  Irregular narrow-complex tachycardias are likely atrial fibrillation or MAT; occasionally atrial flutter is irregular

Wide Complex Tachycardias

·         Monomorphic ventricular tachycardia

·         Polymorphic ventricular tachycardia

·         Supraventricular tachycardia with aberrancy due to intraventricular conduction delay

·         Pre-excitation syndromes

Note: Because ACLS providers may be unable to distinguish between supraventricular and ventricular rhythms, they should be aware that most wide-complex (broad-complex) tachycardias are ventricular in origin.

Wide Complex Tachycardias

The QRS configuration of the 12-lead ECG can help in the differentiation of SVT from VT

Complex rules exist for making the correct rhythm diagnosis by QRS morphology alone.

The 12-lead ECG is, therefore, most useful for looking for AV dissociation.

Cardinal Rule

Rule No 1:  Wide complex tachycardia is VT until proven otherwise

Rule No 2:  Always remember rule No 1

Evaluate the patient’s history

·         A history of coronary artery disease or other structural heart disease suggests ventricular origin.

·         A history of previous aberrant rhythms, accessory pathways, preexisting bundle-branch block, or rate-dependent bundle-branch blocks suggests supraventricular aberrancy


Reviewed 2/28/16