Atrioventricular nodal reentrant tachycardia (AVNRT) happens when the AV node double-fires, sending an extra electrical signal through two tiny pathways in the same area of the heart. This creates a short circuit that triggers a sudden, racing heartbeat. A cardiologist can confirm the diagnosis with an ECG and often resolve it permanently with catheter ablation.
A racing heart that seems to come from nowhere is unsettling. One moment you feel fine, and the next your pulse is pounding so fast you can barely catch your breath. If this has happened to you more than once, you may be dealing with atrioventricular nodal reentrant tachycardia, often shortened to AVNRT. Understanding what this condition is, and what it means when the AV node double-fires, is the first step toward feeling steady again.
What Is Atrioventricular Nodal Reentrant Tachycardia?
Atrioventricular nodal reentrant tachycardia is the most common type of supraventricular tachycardia, a group of conditions that cause abnormally fast heart rhythms originating above the heart’s lower chambers. The AV node acts as the heart’s electrical gatekeeper, passing signals from the upper chambers to the lower chambers in a controlled, steady rhythm. In AVNRT, that gatekeeper malfunctions, allowing a signal to loop back on itself instead of moving forward normally.
When the AV Node Double-Fires: How AVNRT Happens
The phrase “the AV node double-fires” describes exactly what takes place during an episode. A single electrical impulse ends up triggering two heartbeats instead of one, because it gets caught in a loop within the AV node itself.
The Slow and Fast Pathway Explained
Most people have two pathways through the AV node: a slow one and a fast one. Normally, these pathways work together without issue. During AVNRT, an early beat travels down the slow pathway while the fast pathway is still resetting. The signal then climbs back up the fast pathway and re-enters the slow one, creating a self-sustaining electrical circuit. This is the moment the AV node double-fires, and it can repeat itself dozens or even hundreds of times a minute.
Typical vs. Atypical AVNRT
Typical AVNRT follows the slow-fast pattern described above and accounts for the vast majority of cases. Atypical AVNRT reverses the circuit, moving down the fast pathway and back up the slow one. Both forms produce the same unsettling symptoms, though atypical AVNRT is less common and can be trickier to identify on an ECG.
Signs and Symptoms to Know
AVNRT episodes often start and stop suddenly, which can feel alarming even when the condition itself is not dangerous. Common symptoms include:
- Pounding or fluttering heartbeat: Often described as a racing sensation that begins and ends abruptly.
- Lightheadedness or dizziness: Caused by the heart pumping less efficiently during a rapid rhythm.
- Shortness of breath: A result of reduced blood flow during the episode.
- Chest discomfort or anxiety: The sudden onset can understandably trigger worry, even when the rhythm resolves on its own.
You are not imagining these symptoms, and you do not have to just live with them.
How a Cardiologist Diagnoses AVNRT
A cardiologist typically starts with an electrocardiogram (ECG) to capture the heart’s electrical activity during an episode. Because AVNRT can be intermittent, a cardiologist may also recommend an extended monitor or an electrophysiology study, a more detailed test that maps the heart’s electrical pathways and can confirm exactly where the double-firing is occurring.
Treatment Options at a Cardiology Clinic in Brooklyn
Vagal Maneuvers and Medications
Simple techniques, such as bearing down or applying cold water to the face, can sometimes interrupt an episode by stimulating the vagus nerve. When these maneuvers are not enough, a cardiologist may prescribe medications that slow conduction through the AV node and prevent the circuit from forming.
Catheter Ablation
For recurring episodes, catheter ablation offers a long-term solution. This minimally invasive procedure targets the slow pathway responsible for the double-firing and eliminates it, with success rates reported above 95 percent. Many patients experience no further episodes after a single procedure.
Taking the Next Step for a Steadier Heartbeat
Living with an unpredictable heartbeat takes a toll, even when you know the condition is treatable. Our Cardiology team is here to help you understand when your AV node double-fires and to guide you toward lasting relief. Reach out to us today by calling +1-718-367-2555 or visiting us at 1797 Pitkin Avenue, Brooklyn, NY 1121 to schedule a consultation.
