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Wide complex tachycardia: differentiating ventricular tachycardia from supraventricular tachycardia
  1. Wern Yew Ding,
  2. Saagar Mahida
  1. Liverpool Centre for Cardiovascular Science, University of Liverpool and Liverpool Heart & Chest Hospital, Liverpool, UK
  1. Correspondence to Dr Wern Yew Ding, Liverpool Centre for Cardiovascular Science, University of Liverpool and Liverpool Heart & Chest Hospital, Liverpool, UK; dwyew{at}

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Learning objectives

  • Review the underlying principles of physiological cardiac activation.

  • Assess the differences in cardiac activation between ventricular and supraventricular tachycardias, and how these may relate to electrocardiographic changes.

  • Discuss the electrocardiographic algorithms for diagnosis of wide complex tachycardia.


A wide QRS complex tachycardia (WCT) is defined as a tachycardia with QRS duration of >120 ms. Distinguishing between the different potential causes of a WCT can have important implications, particularly in terms of determining the urgency of treatment, deciding between different antiarrhythmic drugs and risk stratification for sudden cardiac death. Potential differential diagnoses for a WCT include ventricular tachycardia (VT), supraventricular tachycardia (SVT) with aberrant conduction, SVT with antegrade conduction via an accessory pathway (AP), ventricular pacing and ECG artefact (box 1). In most cases, paced ventricular activation and ECG artefact can be excluded with relative ease based on the ECG features and background clinical history. On the other hand, distinguishing VT from SVT may represent a challenge. In this regard, sufficient knowledge of the background history and detailed analysis of the ECG are central to making an accurate diagnosis.1 2 This article will outline the approaches and algorithms for distinguishing between different forms of WCT with a particular focus on ECG characteristics to distinguishing VT from SVT.

Box 1

Differential diagnosis of wide complex tachycardia

Causes of wide complex tachycardia

  • Ventricular tachycardia

  • Supraventricular tachycardia with aberrancy

  • Supraventricular tachycardia with antegrade accessory pathway conduction

  • Ventricular pacing

  • Electrocardiogram artefact

Cardiac activation during VT and SVT

In general, there are two major differences in the activation patterns that can be exploited when distinguishing VT from SVT: (1) the relationship between atrial and ventricular activation, and (2) the sequence of ventricular activation.

Relationship between atrium and ventricle

During SVT, the tachycardia originates from the atria or involves the atria in the tachycardia circuit. During VT, cardiac activation originates from the ventricle and atrial activation may or may not be linked to ventricular activation. In the event of VT …

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  • Contributors WYD performed the literature search and drafted the manuscript. SM provided critical revisions. All authors approve the final version of the manuscript for publication.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Patient and public involvement Patients and/or the public were not involved in the design, or conduct, or reporting, or dissemination plans of this research.

  • Provenance and peer review Commissioned; externally peer reviewed.

  • Author note References which include a * are considered to be key references.