Supraventricular Tachycardia
Supraventricular tachycardia is a condition where your heart suddenly beats much faster than normal, with the rapid rhythm starting in the upper chambers of your heart. While it’s usually not life-threatening, understanding this condition can help you manage episodes and know when to seek help.
Table of contents
- What is supraventricular tachycardia?
- Types of supraventricular tachycardia
- Symptoms and how it feels
- What causes supraventricular tachycardia?
- Who is at risk?
- How is it diagnosed?
- Treatment options
- Living with supraventricular tachycardia
- Possible complications
What is supraventricular tachycardia?
Supraventricular tachycardia, often called SVT, is a type of irregular heartbeat (also called an arrhythmia) where your heart suddenly beats much faster than normal.[1] The name tells us where the problem starts: “supraventricular” means above the ventricles, which are the lower chambers of your heart. So SVT begins in the upper chambers, called atria.[2]
A normal resting heart beats about 60 to 100 times per minute.[1] During SVT, your heart beats more than 100 times a minute, typically between 150 and 220 beats per minute.[1] Some episodes may even reach 250 beats per minute.[5] When your heart beats this fast, there isn’t enough time for the heart chambers to fill with blood before they squeeze and pump it out. This means your heart may not send enough blood to the rest of your body.[2]
SVT is caused by a problem in the electrical system that controls your heart rhythm.[4] Think of your heart as having special pacemaker cells that send out regular electrical signals to make your heart beat. In SVT, an area outside these normal pacemaker cells begins to fire quickly, or electrical signals get caught in a loop that goes round and round.[6] This causes the rapid heartbeat until something interrupts the abnormal circuit and your heart returns to its normal rhythm.[7]
Types of supraventricular tachycardia
SVT is actually a general term for several different types of fast heart rhythms that start in the upper chambers of the heart.[3] The most common types include:
- Atrioventricular nodal reentrant tachycardia (AVNRT): This is the most common type of SVT in adults. It happens when you have two channels or pathways through the AV node (a special area between the upper and lower chambers) instead of just one. The electrical signal gets into a looping circuit, going down one channel and up the other.[6]
- Atrioventricular reciprocating tachycardia (AVRT): This is the second most common type. You’re born with an extra electrical connection between the upper and lower chambers called an accessory pathway. This creates a looping electrical circuit that keeps going until it’s interrupted.[6] It’s most commonly seen in younger people.[1]
- Atrial tachycardia: This type is more commonly seen in people who have heart disease and doesn’t involve the AV node.[1]
Other less common types include sinus nodal reentrant tachycardia, inappropriate sinus tachycardia, multifocal atrial tachycardia, junctional ectopic tachycardia, and nonparoxysmal junctional tachycardia.[1] Different types also include premature atrial contractions, atrial fibrillation, and atrial flutter.[2]
Symptoms and how it feels
The main symptom of SVT is a very fast heartbeat that comes on suddenly and may last from a few minutes to a few hours.[1] Some people experience episodes several times a day, while others may have them only once a year.[4] The fast heartbeat may come and go suddenly, and it can happen when you’re resting or doing exercise.[4]
You might not have any symptoms with SVT, but whether you realize it or not, your heart is beating more than 100 times per minute while at rest.[2] When symptoms do occur, they may include:
- Pounding or fluttering feelings in the chest (called palpitations)[1]
- Chest pain or discomfort[2]
- Feeling weak, tired, or lightheaded[1]
- Feeling dizzy[2]
- Shortness of breath (called dyspnea)[2]
- Sweating[2]
- Passing out (in some cases)[2]
Symptoms may range from mild to severe.[2] Many people have their first symptoms between 25 and 40 years old.[4]
What causes supraventricular tachycardia?
SVT happens when the electrical system that controls your heart rhythm is not working properly.[4] A problem with your heart’s electrical signals or circuitry causes the condition.[2] In most people with SVT, the heart’s structure is normal, but there are abnormal electrical connections or circuits that can trigger fast heart rhythms.[6]
Some people may not be aware of what brings their symptoms on. Others have clear “triggers” that start their SVT episodes.[2] Common triggers that can bring about symptoms include:
- Caffeine in coffee, chocolate, and some sodas and teas[5]
- Alcohol[2]
- Cigarette smoke[2]
- Stress (physical or emotional)[2]
- Physical activity or intense exercise[2]
- A shortage of sleep[2]
- Dehydration[2]
- Certain medications, such as beta-agonists for asthma, stimulants, diet pills, and over-the-counter cold and cough medicines[3]
- Illegal drugs such as cocaine and methamphetamine[3]
Who is at risk?
Both children and adults can get supraventricular tachycardia, and it can happen at any age.[2] However, it often starts for the first time in children and young adults.[4] Risk factors for SVT include:
- Being female[2]
- Having anxiety[2]
- Drinking more alcohol than the suggested limit[2]
- Using tobacco products[2]
- Drinking more caffeinated beverages than the suggested limit[2]
- Doing hard physical training[2]
- Having lung disease, heart issues, thyroid disease, or diabetes[2]
- Being pregnant[2]
How is it diagnosed?
To diagnose supraventricular tachycardia, a healthcare professional will examine you, listen to your heart, and take your blood pressure.[8] You will usually be asked questions about your symptoms, health habits, and medical history.[8] During a physical exam, your provider will also ask about the symptoms you’ve been having.[2]
Tests to diagnose SVT may include:
- Electrocardiogram (ECG or EKG): This quick test checks the heartbeat using sticky patches called electrodes that attach to the chest and sometimes to the arms or legs. An ECG shows how fast or slow the heart is beating.[8] Some personal devices, such as smartwatches, can do ECGs.[8]
- Blood tests: A sample of blood is taken to check for other causes of a fast heartbeat, such as thyroid disease.[8]
- Holter monitor: This portable ECG device is worn for one to two days to record the heart’s activity during daily activities. It can spot irregular heartbeats that aren’t found during a regular ECG.[8]
- Event recorder: This device is like a Holter monitor, but it records only at certain times for a few minutes at a time. It’s typically worn for about 30 days. You usually push a button when you feel symptoms, though some devices automatically record when an irregular heartbeat occurs.[8]
- Implantable loop recorder: This device records the heartbeat continuously for up to three years. It shows how the heart is beating during daily activities.[8]
- Echocardiogram: Sound waves are used to create images of the beating heart. This test can show how blood flows through the heart and heart valves.[8]
- Exercise stress test: Exercise may trigger or worsen supraventricular tachycardia, so this test helps see how your heart responds to physical activity.[8]
Treatment options
Most people with supraventricular tachycardia don’t need treatment if episodes are short and don’t cause symptoms.[1] You may not need SVT treatment if your episodes only last a few minutes and don’t bother you.[4] However, if you have symptoms, frequent episodes, or both, then you will likely require treatment.[14]
Treatment options include:
At-home treatments and vagal maneuvers: When an episode starts suddenly, your doctor may teach you to try certain actions called vagal maneuvers. These are simple techniques that can help stop episodes when they happen.[4] They include:
- Lying down[2]
- Putting an ice-cold towel on your face[2]
- Bearing down (trying to breathe out with your stomach muscles but not letting air out of your nose or mouth)[7]
- Coughing or holding your breath[7]
Your doctor can show you how to do these safely.[11]
Medications: If lifestyle changes and vagal maneuvers don’t help, medicines can be used. Your doctor may prescribe daily medications to help prevent SVT episodes from occurring or to slow heart rates during SVT episodes.[14] Commonly prescribed medications include beta-blockers, calcium channel blockers, and other medicines called antiarrhythmic drugs.[14] Some people may be given a short-acting medicine that they can take when episodes occur.[11]
If your heart rate cannot be slowed using vagal maneuvers, you may need to go to the emergency room, where a fast-acting medicine can be given through a vein to slow your heart rate.[11]
Cardioversion: In rare cases, you might require an electrical shock to get your heart back into a normal rhythm.[4] This procedure is called cardioversion. It may be needed if you are having severe symptoms and your heart rate doesn’t go back to normal using vagal maneuvers or fast-acting medicines.[11]
Catheter ablation: Many people with SVT have a procedure called catheter ablation. This procedure can stop the rhythm problem in most people and may permanently cure the problem.[4] During an ablation, a thin, flexible tube (catheter) is placed through a vein, typically in your leg, then guided to your heart.[14] Your doctor uses this to find the area in your heart causing the electrical problems that trigger SVT. The doctor then destroys this area either by burning or freezing that part of the heart.[14] Ablation can be considered as a primary treatment for certain types of SVT, and it may also be considered if you often have symptoms despite being on medication.[14] Although ablation is considered safe and effective, it does have some rare but serious risks.[4]
Living with supraventricular tachycardia
If your episodes of supraventricular tachycardia only last a few minutes and do not bother you, you may not need medical treatment.[4] You can make changes to your lifestyle to reduce your chances of having episodes and help manage the condition.
Identify and avoid triggers: One way to prevent SVT is to work with your healthcare team to identify triggers that may cause the abnormal heart rhythm.[19] Keep a diary to help you pinpoint your own triggers. Write down when your heart goes out of rhythm and what you were doing at the time.[16] Common triggers to avoid include:
- Caffeine in coffee, chocolate, and some sodas and teas[4]
- Alcohol[19]
- Cigarettes and other tobacco products[19]
- Cocaine, methamphetamine, and other illegal drugs[19]
- Stimulants, diet pills, and over-the-counter cold and cough medicines[19]
If you smoke, quit or cut back as much as you can.[2] Cutting down on the amount of caffeine or alcohol you drink and stopping or cutting back on smoking can help.[4]
Manage stress: Stress is a common trigger for SVT.[2] Finding effective ways to manage it is important. Relaxation techniques like deep breathing, meditation, yoga, and progressive muscle relaxation can help lower your heart rate and keep stress levels in check.[16] Setting aside just a few minutes each day to focus on relaxation can have a lasting impact on your overall health.[17]
Follow a heart-healthy diet: A balanced diet that emphasizes fruits, vegetables, whole grains, lean proteins, and healthy fats can support your heart.[16] Foods high in potassium and magnesium are particularly helpful. Find potassium in foods such as bananas, oranges, spinach, sweet potatoes, tomatoes, and yogurt. High-magnesium foods include almonds, avocados, black beans, brown rice, and spinach.[16] Reducing sodium intake is also essential.[17]
Try to cut back on foods and drinks that might trigger a faster heartbeat, including alcohol, caffeine, spicy foods, and very cold drinks.[16]
Stay hydrated: Dehydration can trigger SVT episodes, so staying hydrated is essential.[20] Make it a habit to drink plenty of water throughout the day.[17]
Exercise safely: Regular physical activity is important for keeping your heart strong, but you need to be careful about fitness.[16] Check with your doctor to see how much exercise and which types are safest for you. Start any new exercise program slowly and add more time and effort only when your heart is up to it.[16] Learn how to check your pulse while you work out and ask your doctor what to do if your heartbeat kicks into high gear.[16]
Get quality sleep: Sleep is essential for maintaining a healthy heart rhythm. Poor sleep patterns or sleep disorders can make SVT symptoms worse.[17] Aim for seven to eight hours of restful sleep each night and establish a consistent bedtime routine.[17]
Monitor your heart rate: Regularly monitoring your heart rate can help identify triggers and patterns.[20] Use a heart rate monitor or a smartwatch to record your pulse.[20]
Take medications as prescribed: If your doctor has prescribed medicines, take them exactly as directed.[16] Don’t skip a dose or stop taking the drug without first checking with your doctor.[16]
Stay connected with your healthcare team: Regular check-ins with your healthcare provider are essential for managing SVT.[17] If new symptoms develop or your symptoms become worse, call your doctor.[23]
Possible complications
SVT isn’t life-threatening in most cases.[2] It is rarely life-threatening, but you may need treatment in hospital if you keep having long episodes.[4] However, it can be life-threatening for people with other heart issues.[2]
A serious case of SVT may lead to:
You should call emergency services immediately if you’ve been diagnosed with supraventricular tachycardia and your episode has lasted longer than usual, or if you have a fast heartbeat with shortness of breath, chest pain, or feeling faint.[4]
SVT, paroxysmal supraventricular tachycardia, PSVT