Official reprint from UpToDate®
www.uptodate.com ©2016 UpToDate®

Clinical manifestations, diagnosis, and evaluation of narrow QRS complex tachycardias

Leonard I Ganz, MD, FHRS, FACC
Section Editors
Bradley P Knight, MD, FACC
Ary L Goldberger, MD
James Hoekstra, MD
Deputy Editor
Brian C Downey, MD, FACC


Tachycardias are broadly categorized based upon the width of the QRS complex on the electrocardiogram (ECG) [1].

A narrow QRS complex (<120 milliseconds) reflects rapid activation of the ventricles via the normal His-Purkinje system, which in turn suggests that the arrhythmia originates above or within the His bundle (ie, a supraventricular tachycardia). The site of origin may be in the sinus node, the atria, the atrioventricular (AV) node, the His bundle, or some combination of these sites.

A widened QRS (≥120 milliseconds) occurs when ventricular activation is abnormally slow. The most common reason that a QRS is widened is because the arrhythmia originates below the His bundle in the bundle branches, Purkinje fibers, or ventricular myocardium (eg, ventricular tachycardia). Alternatively, a supraventricular arrhythmia can produce a widened QRS if there are either pre-existing or rate-related abnormalities within the His-Purkinje system (eg, supraventricular tachycardia with aberrancy), or if conduction occurs over an accessory pathway. Thus, wide QRS complex tachycardias may be either supraventricular or ventricular in origin. (See "Approach to the diagnosis of wide QRS complex tachycardias".)

This topic will provide a broad overview of the different causes of narrow QRS complex tachycardia and an approach to their evaluation and diagnosis. Detailed discussions of specific narrow complex tachycardias (eg, AVNRT, AVRT, and AT) and a broad discussion of wide complex tachycardias are presented separately. (See "Approach to the diagnosis of wide QRS complex tachycardias".)


Reentry is the most common cause of narrow QRS complex tachycardia. Increased automaticity and triggered activity occur less frequently [2].


Subscribers log in here

To continue reading this article, you must log in with your personal, hospital, or group practice subscription. For more information or to purchase a personal subscription, click below on the option that best describes you:
Literature review current through: Apr 2016. | This topic last updated: Jun 25, 2015.
The content on the UpToDate website is not intended nor recommended as a substitute for medical advice, diagnosis, or treatment. Always seek the advice of your own physician or other qualified health care professional regarding any medical questions or conditions. The use of this website is governed by the UpToDate Terms of Use ©2016 UpToDate, Inc.
  1. Ganz LI, Friedman PL. Supraventricular tachycardia. N Engl J Med 1995; 332:162.
  2. Blomström-Lundqvist C, Scheinman MM, Aliot EM, et al. ACC/AHA/ESC guidelines for the management of patients with supraventricular arrhythmias--executive summary: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and the European Society of Cardiology Committee for Practice Guidelines (Writing Committee to Develop Guidelines for the Management of Patients With Supraventricular Arrhythmias). Circulation 2003; 108:1871.
  3. Ferguson JD, DiMarco JP. Contemporary management of paroxysmal supraventricular tachycardia. Circulation 2003; 107:1096.
  4. Katritsis DG, Josephson ME. Differential diagnosis of regular, narrow-QRS tachycardias. Heart Rhythm 2015; 12:1667.
  5. Orejarena LA, Vidaillet H Jr, DeStefano F, et al. Paroxysmal supraventricular tachycardia in the general population. J Am Coll Cardiol 1998; 31:150.
  6. Trohman RG. Supraventricular tachycardia: implications for the intensivist. Crit Care Med 2000; 28:N129.
  7. Kalbfleisch SJ, el-Atassi R, Calkins H, et al. Differentiation of paroxysmal narrow QRS complex tachycardias using the 12-lead electrocardiogram. J Am Coll Cardiol 1993; 21:85.
  8. Accardi AJ, Miller R, Holmes JF. Enhanced diagnosis of narrow complex tachycardias with increased electrocardiograph speed. J Emerg Med 2002; 22:123.
  9. Link MS. Clinical practice. Evaluation and initial treatment of supraventricular tachycardia. N Engl J Med 2012; 367:1438.
  10. Smith GD, Dyson K, Taylor D, et al. Effectiveness of the Valsalva Manoeuvre for reversion of supraventricular tachycardia. Cochrane Database Syst Rev 2013; 3:CD009502.
  11. Ellenbogen KA, Thames MD, DiMarco JP, et al. Electrophysiological effects of adenosine in the transplanted human heart. Evidence of supersensitivity. Circulation 1990; 81:821.
  12. Chauhan VS, Krahn AD, Klein GJ, et al. Supraventricular tachycardia. Med Clin North Am 2001; 85:193.
  13. Akhtar M, Jazayeri MR, Sra J, et al. Atrioventricular nodal reentry. Clinical, electrophysiological, and therapeutic considerations. Circulation 1993; 88:282.