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.
Supraventricular tachycardia treatment
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.
Locations for supraventricular tachycardia
At Baylor Scott & White, you’ll find heart teams with extensive experience in identifying and treating supraventricular tachycardia (SVT). We can help you find care at a location in North and Central Texas best suited to your needs.
Loading locations...
Loading locations...