What Is Atrioventricular Nodal Reentrant Tachycardia (AVNRT?

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Atrioventricular nodal reentrant tachycardia (AVNRT) is a rapid cardiac arrhythmia (irregular heartbeat) that starts suddenly and without warning and stops just as abruptly.

It most commonly affects younger adults. The average age at which AVNRT first occurs is 32, and most people with this arrhythmia will have their first episode by age 50. Once it first happens, it may become a recurrent problem.

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AVNRT is the most common type of supraventricular tachycardia (SVT) in adults.

AVNRT is one of the reentrant tachycardias (tachycardia simply refers to a rapid heart rate). With every reentrant tachycardia, there is an abnormal electrical connection somewhere in the heart that forms a potential electrical circuit.

When one of the heart’s electrical impulses enters this circuit under just the right circumstances, it can become “captured” within the circuit. When this happens, it starts spinning around and around the circuit. Every time it does, the electrical impulse produces a new heartbeat, resulting in tachycardia.

As is the case with most reentrant SVTs, people with AVNRT are born with an extra electrical connection in the heart. In AVNRT, the extra connection and the entire reentrant circuit that produces the arrhythmia is located within or very close to the tiny atrioventricular node (AV node)—hence the name AV nodal reentrant tachycardia.

AVNRT Symptoms

The symptoms of AVNRT are typical for SVT. They generally include one or more of the following:

  • Sudden onset of palpitations
  • Lightheadedness
  • Dizziness
  • Shortness of breath

One symptom that is often seen in AVNRT, but that occurs less frequently with other kinds of SVT, is a sensation of pounding in the neck.

During episodes of AVNRT, the atria and the ventricles are beating at the same time. Because the atria cannot eject blood into the ventricles, it is pushed upward into the neck vein—resulting in a pounding sensation.

Episodes of AVNRT start and stop quite suddenly, and they commonly last from a few minutes to several hours.

Starting and Stopping AVNRT

The AV node is very sensitive to changes in the autonomic nervous system, the part of the nervous system that controls blood vessels and internal organs. Hence, changes in either sympathetic nervous tone (a stress response) or in the tone of the vagus nerve (parasympathetic tone, or a relaxation response) can have a major effect on the AV node.

Because much of the reentrant circuit in AVNRT is contained within the AV node, changes in the autonomic tone can have a profound effect on the arrhythmia.

While AVNRT most commonly begins without any apparent triggers, in some people it can start with exercise, periods of emotional stress, or other situations that increase sympathetic tone. In others, it can start after ingesting alcohol, tea, or coffee.

Patients with AVNRT can often stop their episodes of tachycardia by doing things to suddenly increase the tone of the vagus nerve. Performing the Valsalva maneuver often works, though more drastic steps (such as immersing their face in ice water for a few seconds) may sometimes be necessary.

Medical Treatment

Healthcare providers can treat acute episodes of AVNRT fairly quickly and easily. First, they generally guide the patient through a few attempts at increasing their vagal tone.

If that fails to stop the arrhythmia, an intravenous injection of adenosine or verapamil (a calcium channel blocker) will usually work quickly and reliably. The more difficult medical question pertains to long-term therapy for AVNRT.

Though the arrhythmia is life-disrupting, it is not life-threatening. As such, the aggressiveness of treatment ought to reflect the extent of the impact of symptoms on the patient.

If episodes are quite infrequent, reasonably well-tolerated, and can be terminated pretty reliably by vagal maneuvers, then likely nothing more needs to be done.

However, if episodes of AVNRT are disruptive to a patient’s life, which is often the case, then treatment ought to be strongly considered. Treatment with beta-blockers or calcium channel blockers is variably effective in reducing the frequency of AVNRT. In most patients, these drugs have few side effects.

If the arrhythmia is not sufficiently controlled, then one of the antiarrhythmic drugs might be tried. However, these drugs often have side effects, and they are only moderately effective in treating AVNRT.

The most effective means of treating AVNRT today is to use ablation therapy, a catheterization procedure. With ablation therapy, the abnormal electrical connection in or near the AV node is carefully mapped and then is ablated, usually with radiofrequency energy.

AVNRT can be completely cured with ablation therapy in over 95% of cases. It should be strongly considered by anyone in whom AVNRT is a major problem, especially if it has not been controlled using beta-blockers or calcium blockers.

A Word From Verywell

While AVNRT is not life-threatening, it can be bothersome for some people, especially since symptoms begin and end so suddenly.

If you aren't sure what activities are triggering your symptoms, consider keeping a journal of each episode. Take note of when symptoms began and what you were doing at the time. You may find that there is no apparent trigger at all, but nonetheless, this record can help your healthcare provider find the best treatment plan for you.

3 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Page RL, Joglar JA, Caldwell MA, et al. 2015 ACC/AHA/HRS guideline for the management of adult patients With supraventricular tachycardia: A report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society. Circulation. 2015 Sep;133(14):e506-e574. doi:10.1161/CIR.0000000000000311

  2. Matta M, Devecchi C, De Vecchi F, Rametta F. Atrioventricular nodal reentrant tachycardia: current perspectivesResearch Reports in Clinical Cardiology. 2020 Dec;11(1):1-6. doi:10.2147/RRCC.S186616

  3. Brugada J, Katritsis DG, Arbelo E, et al. 2019 ESC Guidelines for the management of patients with supraventricular tachycardia. European Heart Journal. 2020;41(5):655-720. doi: 10.1093/eurheartj/ehz467

By Richard N. Fogoros, MD
Richard N. Fogoros, MD, is a retired professor of medicine and board-certified in internal medicine, clinical cardiology, and clinical electrophysiology.