AV nodal reentry tachycardia

The AV node is the only electrical connection between the atria and the ventricles. In a small portion of the population, the AV node consists of two functionally distinct pathways: a fast pathway and a slow pathway. Under certain circumstances—usually triggered by an early extra beat—an electrical circuit can form between these two pathways, repeatedly stimulating the heart in rapid succession. The resulting heart rate typically ranges between 150 and 250 beats per minute.

Since the heart itself is structurally healthy, pumping capacity is usually maintained. However, the tachycardia is often felt by those affected as a strong, sudden racing of the heart and can significantly impair quality of life.

Who is affected?

AVNRT can occur at any age, but is more common in younger adults and more frequently in women. Structural heart disease is generally not present. It is not uncommon for patients to report episodes lasting for years before a diagnosis is made.

What are the symptoms of AVNRT?

Episodes typically begin suddenly and end just as abruptly. Characteristic symptoms include:

• Sudden, racing heartbeat (150–250 bpm)
• Tightness or pressure in the chest
• Shortness of breath
• Dizziness or lightheadedness
• Urge to urinate shortly after the episode (due to a hormonal response to increased pressure in the atrium)
• In rare cases, brief fainting (presyncope / syncope)

Important: A sudden onset and equally abrupt cessation are strong indicators of a supraventricular tachycardia such as AVNRT.

How is AVNRT diagnosed?

Diagnosis usually requires recording an ECG during an episode. Since episodes are rarely predictable, the following methods are available:

12-lead ECG during an episode: Shows narrow-complex tachycardia with a P wave that is often not visible or is hidden directly behind the QRS complex.

Long-term ECG (24–48 hours or longer): Useful for frequent episodes.

Event recorder / implantable loop recorder: For rare but symptomatic episodes.

Electrophysiological study (EPS): The gold standard—both for definitive diagnosis and as the first step in catheter ablation. In the cardiac catheterization laboratory, the tachycardia is specifically triggered and the mechanism is precisely mapped. 

Treatment of AVNRT

Acute measures during an episode

Vagal maneuvers can often interrupt an ongoing AVNRT: the Valsalva maneuver (pressing forcefully as if against a blocked airway), cold stimulation of the face (cold water), or the modified Valsalva technique (pressing while lying down with the upper body elevated) are easy to perform and often effective. If these are insufficient, intravenous adenosine can immediately terminate the episode.

Long-term drug therapy

Beta-blockers or calcium channel blockers (verapamil, diltiazem) can reduce the frequency and severity of episodes. However, they do not provide a cure—recurrences are common, and lifelong medication is not a satisfactory solution for many patients.

Catheter ablation—the definitive solution

Catheter ablation of the slow pathway (slow pathway ablation) is the treatment of choice. It offers a permanent cure rate of over 95% and has a very low complication rate. The procedure typically takes 60–90 minutes and is performed under local anesthesia with light sedation. An inpatient stay is generally not required.

At Swiss Ablation, we perform AVNRT ablation in our own hybrid cardiac catheterization laboratory. Our team’s high caseload and many years of experience ensure optimal results with minimal risk.

Why Swiss Ablation?

Cardiac arrhythmias are our exclusive area of expertise. Unlike in a general cardiology practice or a large hospital, our rhythmologist and ablation specialist serves as your direct point of contact from the initial diagnosis through follow-up care—without waiting times or referrals.

If you suffer from paroxysmal tachycardia or have already received a diagnosis and would like a second opinion, we look forward to hearing from you.