What is supraventricular tachycardia?

Supraventricular tachycardia (SVT) is a type of arrhythmia when your heart beats much faster than normal. It happens when the electrical signals that control your heartbeat don’t function correctly and create a loop above the heart’s lower chambers (the ventricles). While episodes can feel scary, SVT isn’t usually life-threatening.

You might feel a fluttering in your chest, lightheaded or short of breath when SVT kicks in. These episodes can last for a few seconds or several hours and often come and go without warning. The good news is that SVT is treatable and, in many cases, manageable with lifestyle changes, medications or procedures that help restore your heart’s normal rhythm.

Types of supraventricular tachycardia

SVT isn’t just one condition. It's a group of related heart rhythm problems that all start above the ventricles. Doctors classify its various types based on how electrical signals travel from the upper chamber (atria) to the ventricles.

Here are the most common types:

  • Atrioventricular nodal reentrant tachycardia (AVNRT): The most common type, AVNRT happens when a looping electrical signal gets stuck in a circuit near the heart’s AV node (the heart’s electrical relay station between the atria and ventricles).
  • Atrioventricular reciprocating tachycardia (AVRT): This type involves an extra electrical pathway between the upper and lower chambers of the heart.
  • Atrial tachycardia: This form starts in the atria (the heart’s upper chambers), where one area fires off electrical signals faster than normal, leading to a rapid heartbeat.

Symptoms of supraventricular tachycardia

Supraventricular tachycardia (SVT) often shows up suddenly and can feel different from person to person. Some people don’t have any symptoms and don’t know they have SVT until it’s picked up during a routine exam. Others may feel something is off with their heart rhythm. Episodes can last just a few seconds or much longer and may disrupt daily activities or leave you feeling unsettled.

Common symptoms include:

  • Chest discomfort or pain
  • Dizziness or lightheadedness
  • Fainting
  • Fatigue
  • Heart palpitations (rapid, fluttering or pounding heartbeats)
  • Shortness of breath

When to see a doctor

If your heart suddenly starts racing and it happens often or lasts more than a few minutes, it’s a good idea to see a doctor, who can help you understand what’s going on and get the right care.

Chest discomfort, dizziness, lightheadedness and shortness of breath are also symptoms of a heart attack. Never hesitate to call 911 if you have those symptoms, as well as a racing heart.

What causes supraventricular tachycardia?

SVT starts when electrical signals in your heart get off track, causing it to beat much faster than it should. In most cases, SVT happens because of extra or abnormal pathways in the heart’s electrical system. Some people are born with these abnormal pathways, while others develop them later due to heart conditions.

An episode of SVT can be caused by things like stress, caffeine, alcohol or certain medications, but episodes can also occur for no apparent reason. Knowing what triggers your symptoms and working with your care team can help you stay ahead of episodes and feel more in control.

Risk factors for supraventricular tachycardia

Supraventricular tachycardia (SVT) affects people of all ages, but certain traits, health conditions and lifestyle habits can increase your chances of developing SVT or having an SVT episode. These factors may affect the heart’s structure or its electrical system over time.

Risk factors for SVT include:

  • Age: Although SVT can occur in children and young adults, the condition is more common in people over age 65.
  • Anemia: Anemia (low red blood cell count) can cause or worsen a rapid heart rate.
  • Electrolyte imbalances: Low levels of potassium, magnesium or calcium can affect the heart’s ability to maintain a steady rhythm.
  • Family history: Having a family history of SVT increases your risk of developing it.
  • Heart disease: Conditions such as high blood pressure, congenital heart disease, and coronary artery disease can increase your risk of SVT.
  • Heart surgery: Having a previous heart surgery can predispose you to SVT.
  • High levels of stress: Emotional stress can affect your heart’s electrical system and may trigger SVT episodes.
  • Sex: SVT occurs more often in women than men.
  • Stimulant use: Caffeine, tobacco and some illicit drugs can trigger rapid heart rhythms in some people.
  • Thyroid issues: An overactive thyroid (hyperthyroidism) can increase the risk of SVT by speeding up your heart rate.

Complications of SVT

Although many people find that SVT is manageable, it's important to remember that the condition can lead to significant health concerns if left unchecked. Understanding these complications not only empowers you to make informed decisions about your care but also highlights the importance of regular monitoring and communication with your healthcare team.

Here are some key SVT complications to keep in mind:

  • Heart failure: Prolonged rapid heart rates can weaken the heart muscle over time.
  • Sudden cardiac arrest: Some types of SVT can lead to severe increases in your heart rate that can cause your heart to stop working suddenly.

Diagnosing supraventricular tachycardia

Supraventricular tachycardia (SVT) can sometimes be tricky to diagnose, especially if episodes are brief or happen infrequently. Getting an accurate diagnosis is the first step toward finding answers and feeling better. Your care team will gather details about your symptoms, review your medical history and use a few simple tests to get a clearer picture of what’s going on.

  • Medical history and exam

    Your healthcare provider will ask you about your symptoms, their frequency, duration and any potential triggers. They’ll also perform a physical exam to measure your heart rate, heart rhythm and overall heart and vascular health.

  • Imaging and tests

    Based on the results of your medical history and exam, your doctor may order one of the following tests:

    • Electrocardiogram (EKG): This quick, noninvasive test records your heart’s electrical activity. It helps detect abnormal rhythms that may indicate SVT.
    • Heart monitor: These wearable devices track your heart rhythm for a day or longer while you go about your daily life. They can pick up irregular heart rhythms and patterns that a short EKG might miss.
    • Implantable loop recorder: These are implanted under local anesthesia with a battery life of several years. These can be helpful to diagnose rare occurrences.
    • Electrophysiology study: This minimally invasive test maps your heart’s electrical system from the inside. It pinpoints the source of SVT and helps guide treatment decisions.

Supraventricular tachycardia treatment

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You may not need treatment for SVT, but your doctor may want to slow your heart rate, prevent future episodes or address any underlying causes. Your care plan will depend on the type of SVT you have, how often symptoms occur and your overall health. A cardiologist may recommend lifestyle changes, medications or procedures to help you feel better and stay active.

If your rapid heart rate is considered a medical emergency, you may need cardioversion, a procedure to deliver an electrical shock to your heart and restore its natural rhythm.

Vagal maneuvers

Your heartbeat is controlled by your vagus nerve. Vagal maneuvers are techniques you or your doctor can perform that target the vagus nerve and help slow your heart rate.

For example, coughing, bearing down (like you’re having a bowel movement) and holding your breath may help reduce faulty electrical signals. Ask your doctor which vagal maneuvers may help so you can learn which ones to do and how to do them correctly.

Medication

Medications may be used to help slow down a fast heartbeat or prevent supraventricular tachycardia episodes from happening in the first place. Your cardiologist will work with you to choose the right medication based on your symptoms, health history and how often SVT occurs. Some medicines may be used short term, while others are part of long-term care.

Medications for SVT include:

  • Beta blockers: These medications slow the heart rate and reduce the frequency of episodes.
  • Calcium channel blockers: Similar to beta blockers, these medications slow the heart rate and reduce the frequency of episodes.
  • Digoxin: This medication can treat many forms of heart arrhythmias by stabilizing the heart's electrical activity and preventing abnormal rhythms.
  • Antiarrhythmics: These are a class of drugs that affect various electrical channels in the heart to prevent the impulses that lead to SVT.

Surgery and procedures

If lifestyle changes and medication aren’t enough to manage SVT, your cardiologist may recommend a procedure. These are usually reserved for more frequent or severe episodes. The goal is to correct the problem at its source, often by targeting the abnormal electrical pathways in the heart that trigger SVT.

  • Catheter ablation: This minimally invasive procedure destroys the abnormal electrical pathway causing SVT. A cardiac electrophysiologist performs it through the veins that run between your leg and belly.
  • Pacemaker implantation: In rare cases, you may need a device implanted to regulate your heart rhythm.

Frequently asked questions

  • Is supraventricular tachycardia (SVT) dangerous?

    SVT is usually not life-threatening, especially when properly managed. But if left untreated, frequent or prolonged episodes can strain your heart over time, causing potentially serious complications, such as heart failure and stroke.

  • Can supraventricular tachycardia be cured?

    Some types of SVT can be cured, especially with procedures like catheter ablation.

    Catheter ablation targets and destroys the abnormal heart tissue causing the rapid rhythm. It’s a safe, minimally invasive procedure that offers a permanent solution for many people. If ablation isn’t right for you, medications and lifestyle changes can still help manage symptoms effectively.

  • What does supraventricular tachycardia look like on an EKG?

    On an electrocardiogram (EKG), SVT usually shows a fast, regular heartbeat without the normal spacing between beats.

    Because SVT can come and go, your doctor might order a heart monitor that you wear for a day or more to catch an episode that may occur in your daily life. These monitors help confirm the diagnosis and pinpoint the type of SVT you're experiencing.

  • What does supraventricular tachycardia feel like?

    SVT often feels like a sudden pounding, fluttering or racing heartbeat. It can also cause symptoms like dizziness, breathlessness or a sense of unease.

  • How do you calm an SVT episode?

    Vagal maneuvers, like coughing or holding your breath, may calm an SVT episode, as they can help slow your heart rate. If those don’t work, your doctor might prescribe medication to take during episodes. In emergencies, a hospital can use medications or a shock (cardioversion) to restore your heart’s rhythm.

  • Can you live a normal life with supraventricular tachycardia?

    Yes, many people with SVT lead full, active lives with the right care and awareness. Managing triggers, staying active and following your treatment plan are key. If SVT affects your quality of life or feels unmanageable, talk to your doctor about other treatments, such as catheter ablation.

  • What should you not do with SVT?

    You should not drink too much caffeine or alcohol or let your stress levels get too high if you have SVT. These are known triggers of the condition. Some over-the-counter medications can have a stimulant effect, so talk to your doctor about which ones to avoid.

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