Supraventricular Tachycardia (SVT)

Supraventricular tachycardia (SVT) is a fast heart rate that starts in your heart’s upper chambers (atria). This condition can last for seconds, minutes or hours. It’s often associated with symptoms due to your heart’s inability to pump blood when it’s beating too fast.

If you have symptoms, you may think something doesn’t feel right in your chest. You may have the sensation of a racing heart, skipped beats or a fluttering in your chest. Although it may be difficult, noting the details of what you’re experiencing can help a healthcare provider make a diagnosis.

Types of this condition

The most common kinds of SVT are:

• AV (atrioventricular) nodal reentrant tachycardia (AVNRT): A fast heartbeat that comes from signals following a circular path
• AV (atrioventricular) reentrant tachycardia (AVRT): A fast heartbeat that involves at least one extra pathway for signals
• Atrial tachycardia: An abnormal rhythm with your heart’s upper chambers beating faster than normal

Other types of SVT include:

• Premature atrial contractions (PACs)
• Paroxysmal supraventricular tachycardia (PSVT)
• Accessory pathway tachycardias, like Wolff-Parkinson-White (WPW) syndrome
• Junctional tachycardia
• Atrial fibrillation
• Atrial flutter

Symptoms of SVT

A fast heart rate is the main symptom of SVT. Whether you realize it or not, your heart is beating more than 100 times per minute while you’re at rest. A normal resting heart rate is 60 to 100 beats per minute (bpm). Children with SVT can have a heart rate of 180 to 220 bpm.

Other supraventricular tachycardia symptoms may include:

• Chest pain
• Tiredness
• Lightheadedness
• Sweating
• Dizziness
• Passing out
• Heart palpitations (fluttering in your chest)
• Shortness of breath

Symptoms in babies and children may include fainting, poor feeding, vomiting or more sleepiness than usual.

You might not have any SVT symptoms. If you do, they can range from mild to severe.

SVT causes

A problem with your heart’s electrical signals or circuitry causes SVT. Electrical signals tell your heart when to beat. Some people may not be aware of what brings on the symptoms. Others have a clear “trigger” that starts their SVT rhythm.

SVT triggers

Supraventricular tachycardia causes that can bring about symptoms include:

• Stress
• Caffeine
• Alcohol
• Cigarette smoke
• Physical activity
• Lack of sleep
• Dehydration
• Anemia

Risk factors

Children and adults can get supraventricular tachycardia. Your risk of SVT is higher if you:

• Are female
• Are pregnant
• Have anxiety
• Are a child
• Are middle-aged or older
• Drink more alcohol than the suggested limit
• Use tobacco products or other addictive substances
• Drink more caffeine than the suggested limit
• Have lung disease, heart problems, thyroid disease or diabetes
• Do hard physical training

How to lower your risk

You can lower your risk of SVT in these ways:

• Manage your stress.
• Drink less alcohol.
• Stop using tobacco products.
• Consume less caffeine.
• Get more sleep.

You should also keep taking any medicines your healthcare provider has prescribed for you.

Complications of this condition

A serious case of SVT heart disorder may lead to:

• Heart failure
• Unconsciousness
• Cardiac arrest

How doctors diagnose supraventricular tachycardia (SVT)

To diagnose supraventricular tachycardia (SVT), a healthcare provider will do a physical exam. They’ll listen to your heart and ask about any symptoms you’ve been having. They’ll also ask about your medical history and the medications you take.

Some people use wearable heart monitors, like smart watches, which can be helpful in detecting SVT. But your provider will likely request more tests, such as:

• Electrocardiogram (EKG/ECG): Records the electrical activity in your heart
• Heart monitor: Captures your heart’s electrical activity for a longer amount of time
• Blood tests: Check for substances in your blood that can cause abnormal heart rhythms
• Electrophysiology study (EPS): Measures your heart’s electrical activity and shows your heart’s reaction to a trigger
• Tilt table testing: Can help find the cause of fainting episodes

How is it treated?

You may not need SVT treatment. Some people may feel better after getting more sleep, reducing caffeine, drinking less alcohol or quitting smoking. If those changes don’t help, you have lots of other options.

Procedures and maneuvers

Your provider can use these methods for supraventricular tachycardia treatment:

• Vagal maneuvers: Your provider can apply pressure to specific areas of your neck (carotid sinus massage).
• Cardioversion: This procedure uses a shock to return your heart to a normal rhythm.
• Catheter ablation: This procedure uses energy to make scars in your heart that block abnormal electrical signals. In certain cases, your provider may consider catheter ablation before trying medications.
• Implantable cardioverter defibrillator (ICD): This device can deliver a shock when you need it.

At-home treatments

Try one of these first to stop an SVT attack:

• Lie down.
• Put an ice-cold towel on your face.
• Cough.

Medications for SVT

Several medicines can slow down your heart rate:

• Adenosine
• Atropine
• Beta-blockers
• Calcium channel blockers
• Digitalis (digoxin)
• Potassium channel blockers

If your healthcare provider prescribes medicines for you, be sure to follow the instructions for taking them. Also, keep going to your follow-up appointments.

When should I see my healthcare provider?

You should see a provider if you have any symptoms of supraventricular tachycardia.

Call 911 or your local emergency services number if you:

• Have chest pain
• Have trouble breathing
• Feel faint

What can I expect if I have this condition?

SVT isn’t life-threatening in most cases. The outlook is good for most people. But if you have a structural issue with your heart, your prognosis (outlook) may not be as good. It depends on the severity of the problem.

You can manage very infrequent episodes with medications. With successful treatments like catheter ablation, you can do many of your typical activities. Ablation can cure certain forms of SVT rhythm. Catheter ablation has a cure rate that can surpass 95% depending on the SVT type.