Atrioventricular nodal reentry tachycardia (AVNRT)

Overview

Atrioventricular nodal reentry tachycardia (AVNRT) is the most common type of supraventricular tachycardia. Episodes often start and end suddenly, and occur because of a reentrant circuit — also called an accessory pathway — located in or near the AV node that causes the heart to beat prematurely. AVNRT tends to occur more often in young women, but it can affect both males and females of any age.

Diagnosis

Tests and procedures used to diagnose atrioventricular nodal reentry tachycardia may include:

• Blood tests to check thyroid function, heart disease or other conditions that may trigger atrioventricular nodal reentry tachycardia
• Electrocardiogram (ECG) to measure the electrical activity of your heart and measure the timing and duration of each heartbeat
• Holter monitor, which is a portable ECG device designed to record your heart's activity as you go about your routine
• Echocardiogram, which uses sound waves to produce images of your heart's size, structure and motion

Your doctor might also try to trigger an episode with other tests, which may include:

• Stress test, which is typically done on a treadmill or stationary bicycle while your heart activity is monitored
• Electrophysiological testing and mapping, which allows your doctor to see the precise location of the irregular heartbeat (arrhythmia)

Treatment

Most people with atrioventricular nodal reentry tachycardia do not require medical treatment. However, if you experience prolonged or frequent episodes, your doctor may recommend or try:

• Vagal maneuvers. You may be able to stop an episode of AVNRT by using particular maneuvers that include holding your breath and straining, dunking your face in ice water, or coughing.
• Cardioversion. If you're unable to stop an episode on your own using vagal maneuvers, your doctor may use cardioversion, which can be conducted as a procedure or by using medications.
• Medications. If you experience frequent episodes of AVNRT, your doctor may prescribe medication to control your heart rate or restore a normal heart rhythm.
• Catheter ablation. In this procedure, your doctor threads one or more catheters through your blood vessels to your heart. Electrodes at the catheter tips can use heat, extreme cold or radiofrequency energy to damage (ablate) a small spot of heart tissue and create an electrical block along the pathway that's causing your arrhythmia.