Atrioventricular Nodal Reentry Tachycardia (AVNRT) – Symptoms and Causes
Overview
Atrioventricular nodal reentry tachycardia (AVNRT) is a common form of supraventricular tachycardia that causes abnormally fast heart rhythms.
This condition results from abnormal electrical signaling pathways in the heart. AVNRT affects people of all ages but appears more frequently in young women.
Not everyone with AVNRT requires treatment. For those who do, options range from simple physical maneuvers to medications or medical procedures.
Healthcare providers typically develop treatment plans based on symptom severity and how often episodes occur.
Signs and Symptoms
People with AVNRT often have a very rapid heartbeat, which can range from 120 to 280 beats per minute. This fast heart rate typically begins without warning.
Some individuals may not experience any symptoms. However, when symptoms do occur, they might include:
- Feeling a pounding sensation in the neck
- Heart palpitations (fluttering or pounding heartbeat)
- Chest discomfort or tightness
- Dizziness or feeling lightheaded
- Difficulty breathing
- Excessive sweating
- Feeling weak or extremely tired
- Fainting spells or near-fainting episodes
Children with AVNRT may show milder symptoms, such as sweating, feeding problems, skin color changes, and a rapid heartbeat.
When to Contact a Healthcare Provider
Schedule a medical appointment if you notice unexplained changes in your heartbeat pattern.
For infants and children, seek medical care if they show:
- Unusually fast heartbeat
- Unexplained sweating
- Feeding difficulties
- Changes in skin coloration
Emergency situations: Call 911 or emergency services immediately if you experience a very rapid heartbeat that continues for several minutes, especially when accompanied by:
- Chest pain
- Dizziness
- Breathing difficulties
- Weakness
Causes
Atrioventricular nodal reentry tachycardia (AVNRT) happens when the heart’s electrical system doesn’t work correctly. The heart has a natural electrical pathway that controls heartbeats.
People with AVNRT have an extra pathway called a reentrant circuit. This causes the heart to beat too quickly and out of rhythm. When this happens, the heart can’t pump blood effectively.
Medical experts don’t fully understand why some people develop this extra pathway. In some cases, structural changes in the heart may contribute to AVNRT development. These changes might be present from birth or develop over time.
Risk Factors
Young women face a higher chance of developing AVNRT, though it can affect anyone. Various health issues raise the risk, including:
- Heart problems (coronary artery disease, valve disease, heart failure)
- Congenital heart defects
- Previous surgeries of the heart, lung, or throat
- Sleep apnea
- Thyroid disorders
- Lung conditions like COPD
- Poorly managed diabetes
Certain lifestyle factors and substances can trigger AVNRT episodes:
| Lifestyle Triggers | Substances to Avoid |
|---|---|
| Emotional stress | Caffeine |
| Excessive alcohol use* | Tobacco/nicotine products |
| Stimulant drugs (cocaine, methamphetamine) | |
| Some medications for asthma, allergies, and colds |
*Excessive drinking means 15+ drinks weekly for men or 8+ drinks weekly for women.
Complications
Abnormal heart rhythms like AVNRT may lead to serious health issues. People with existing heart problems might face a worsening of their condition when AVNRT occurs.
In rare but severe cases, AVNRT can trigger sudden cardiac arrest, where the heart completely stops beating. This is a life-threatening emergency requiring immediate medical attention.
