Overview

Atrioventricular nodal reentry tachycardia, also called AVNRT, is a type of irregular heartbeat known as an arrhythmia. It is the most common form of supraventricular tachycardia, which means the abnormal rhythm starts in the upper part of the heart.

In AVNRT, the heart suddenly begins to beat very fast, often at a rate higher than 100 beats per minute, and then may stop just as suddenly. These episodes are caused by a problem with the heart’s electrical signaling system. Although AVNRT can occur at any age, it is more commonly seen in young women.

Many people with AVNRT do not require treatment, especially if episodes are rare or mild. When treatment is needed, options may include specific physical maneuvers, medications, or procedures to correct the abnormal heart rhythm.

Symptoms

The most common symptom of atrioventricular nodal reentry tachycardia is a sudden, very fast heartbeat. During an episode, the heart rate may range from about 120 to 280 beats per minute. Episodes often begin abruptly and may end on their own.

When symptoms occur, they may include:

  • Pounding sensations in the neck

  • Pounding or fluttering heartbeat, also known as palpitations

  • Chest pressure, tightness or pain

  • Dizziness or lightheadedness

  • Shortness of breath

  • Sweating

  • Weakness or extreme fatigue

  • Fainting or feeling close to fainting

In children, symptoms are often milder and may include unexplained sweating, difficulty feeding, changes in skin color and a noticeably fast heartbeat.

Causes

Atrioventricular nodal reentry tachycardia is caused by abnormal electrical signaling in the heart. Normally, electrical impulses follow a single, organized pathway through the heart to control the heartbeat.

In AVNRT, an extra electrical pathway exists near the atrioventricular node. This creates a loop, known as a reentrant circuit, that allows electrical signals to travel repeatedly and rapidly. As a result, the heart beats too quickly and cannot pump blood as efficiently as it should.

The exact reason why some people develop this extra pathway is not fully understood. In some cases, changes in the structure of the heart may contribute to the condition.

Risk factors

AVNRT can affect anyone, but certain factors may increase the risk.

Medical risk factors include:

  • Coronary artery disease and other heart conditions

  • Heart valve disease

  • Heart failure

  • Congenital heart defects present at birth

  • Previous surgery involving the heart, lungs or throat

  • Obstructive sleep apnea

  • Thyroid disorders

  • Lung diseases such as chronic obstructive pulmonary disease

  • Poorly controlled diabetes

  • Use of certain medications, including those for asthma, allergies and colds

Lifestyle and other factors that may increase risk include:

  • Emotional stress

  • Caffeine consumption

  • Excessive alcohol use

  • Smoking or nicotine use

  • Use of stimulant drugs such as cocaine or methamphetamine

Complications

Atrioventricular nodal reentry tachycardia is usually not life-threatening, especially in people without underlying heart disease. However, complications can occur in some cases.

Possible complications include worsening of existing heart conditions and, rarely, sudden cardiac arrest, which is the abrupt loss of heart function. Proper evaluation and management can help reduce the risk of serious complications.

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