Atrioventricular reentrant tachycardia (AVRT) is a rhythm problem in your heart that makes it beat too fast. It results from an extra connection between your upper and lower chambers. You might hear it called atrioventricular reciprocating tachycardia.
AVRT is more likely to happen when you're a child or teenager. It doesn't mean you have other heart problems. And symptoms of a fast heart rate are usually mild. But you should still talk to your doctor about your abnormal heartbeat. Rarely, tachycardia from AVRT can be fatal.
What Causes AVRT?
Normally, electricity in your heart follows one path. The signal goes from your upper chambers (atria) to your atrioventricular (AV) node, a cluster of cells at the bottom of your upper right atrium that helps control heart rate and rhythm. The AV node slows down the signal before it passes to your lower chambers (ventricles). That's when your heart contracts, or beats. It usually happens about 60-100 times a minute.
At birth, you can have tissue that makes an extra electrical connection between your atria and ventricles. That's called an accessory pathway (AP) or bypass tract. When you have AVRT, impulses can go through your AV node and this extra, faster circuit. This creates an electricity loop. That's when you get more heartbeats than normal.
In most cases, the signal circles from your atria, through your AV node, down to your ventricles, and back through your AP. But it can go in both directions.
Types of AVRT
Wolff-Parkinson-White (WPW) syndrome. This is the most common kind of AVRT. It's marked by something called preexcitation. That's an early trigger of your ventricles. This happens because your AP sends signals quicker than your AV node. But your AP also needs time to rest. Doctors call this a "refractory period." It allows the signal to loop around your heart.
If you have WPW syndrome, you may not have any heart rhythm problems until your teens or 20s. But sometimes you'll get an abnormal heart rate when you're a baby or when you're past 60. Rarely, your heart might beat so fast it stops working. That's a life-threatening condition called ventricle fibrillation.
Concealed. It’s less common, but the extra electrical impulse can come from your ventricle back through your AV node. This is considered a safer kind of AVRT. That's because your AV node slows down the current.
What Does AVRT Feel Like?
You heart rate may speed up quickly. You may notice it when you exercise. It should only last for a short time. Usually that means a few seconds or minutes. But it could go on for longer. This can cause some unwanted symptoms, like:
How Is AVRT Diagnosed?
The doctor will ask you about your health history. They'll want to know when your symptoms started. You may need blood tests to rule out other health conditions. You should also tell them if you drink caffeine or use other stimulants. Those can make your heart beat faster.
Then they'll check the electrical activity in your heart with a machine. If you have AVRT, your graph will look a certain way. You may get some of the following tests:
- Electrocardiogram. You may hear this called an ECG or an EKG. It's a painless test that quickly shows doctors how fast or slow signals go through your heart.
- Holter and event monitors. These are portable EKGs. You can wear a Holter monitor for a few days, or an event monitor for longer. You may need to use these if your abnormal heart rate doesn't happen very often.
- Electrophysiologic study. Your doctor will put a thin tube (catheter) into your heart. It can help them find the source of your abnormal heartbeat.
How Is AVRT Treated?
It'll depend on your symptoms. There are some things you can try on your own. But if you have AVRT often, you may need surgery. Talk to your doctor about what's right for you.
Your doctor may:
Teach you vagal techniques. Sometimes, these can slow electricity in your heart. That's because they activate your vagus nerve, which goes from your brain to your gut. The doctor can teach you which exercises to do. But they may include:
- Pushing like you're going to poop (bearing down)
- Putting an ice-cold towel on your face
Suggest surgery. A procedure called ablation can get rid of your accessory pathway. The doctor puts a thin tube (catheter) into your heart and uses energy or cold to destroy your AP.
When Is AVRT an Emergency?
If your fast heart rate doesn't stop on its own, you should get help. But you may want to wait about 30 minutes before you call 911.