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Sinoatrial nodal reentrant tachycardia (SANRT)

Munther K Homoud, MD
Section Editor
Samuel Lévy, MD
Deputy Editor
Brian C Downey, MD, FACC


Atrial tachycardias have traditionally been characterized as automatic, triggered, or reentrant. However, the European Society of Cardiology and the North American Society of Pacing and Electrophysiology in 2001 proposed a classification that takes into consideration both anatomic features and electrophysiologic mechanisms [1]. In 2015, the joint American College of Cardiology, American Heart Association, and Heart Rhythm Society guidelines further defined sinus node reentrant tachycardia as "a specific type of focal atrial tachycardia that is due to microreentry arising from the sinus node complex, characterized by abrupt onset and termination, resulting in a P-wave morphology that is indistinguishable from sinus rhythm" [2]. Atrial tachycardia is the overriding term that includes two major categories:

Focal atrial tachycardia due to an automatic, triggered, or microreentrant mechanism

Macroreentrant atrial tachycardia, including typical atrial flutter and other well-characterized macroreentrant circuits in the right and left atrium

Sinoatrial nodal reentrant tachycardia (SANRT), also called sinus node reentry or sinus node reentrant tachycardia, falls into the latter group of macroreentrant arrhythmias. This topic will discuss the mechanisms, clinical manifestations, and treatment of SANRT. Discussions of other specific atrial arrhythmias are presented separately. (See "Focal atrial tachycardia" and "Intraatrial reentrant tachycardia" and "Overview of atrial flutter".)


Initially described in the 1940s, SANRT has often been considered a form of atrial tachycardia. However, SANRT has an activation sequence similar to that of normal sinus rhythm so that the P waves on the surface ECG appear to be normal. In comparison, intraatrial reentry has a different activation sequence of atrial depolarization, leading to a P wave morphology that differs from that of normal sinus rhythm. (See "Intraatrial reentrant tachycardia".)

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Literature review current through: Nov 2017. | This topic last updated: Sep 14, 2017.
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