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What is supraventricular tachycardia?
Supraventricular tachycardia (SVT) means that from time to time your heart beats very fast for a reason other than exercise, high fever, or stress. For most people who have SVT, the heart still works normally to pump blood through the body.
Types of SVT include:
- Atrioventricular nodal re-entrant tachycardia (AVNRT).
- Atrioventricular reciprocating tachycardia (AVRT), including Wolff-Parkinson-White syndrome.
During an episode of SVT, the heart's electrical system doesn't work right, causing the heart to beat very fast. The heart beats at least 100 beats a minute and may reach 300 beats a minute. After treatment or on its own, the heart usually returns to a normal rate of 60 to 100 beats a minute.
SVT may start and end quickly, and you may not have symptoms. SVT becomes a problem when it happens often, lasts a long time, or causes symptoms.
SVT is also called atrial tachycardia, paroxysmal supraventricular tachycardia (PSVT), or paroxysmal atrial tachycardia (PAT).
What causes SVT?
Most episodes of SVT are caused by faulty electrical connections in the heart.
SVT also can be caused by certain medicines. Examples include very high levels of the heart medicine digoxin or the lung medicine theophylline.
Some types of SVT may run in families, such as Wolff-Parkinson-White syndrome. Other types of SVT may be caused by certain health problems, medicines, or surgery.
What are the symptoms?
Some people with SVT have no symptoms. Others may have:
- Palpitations, a feeling that the heart is racing or pounding.
- A pounding pulse.
- A dizzy feeling or may feel light-headed.
Other symptoms include near-fainting or fainting (syncope), shortness of breath, chest pain, throat tightness, and sweating.
How is SVT diagnosed?
Your doctor will diagnose SVT by asking you questions about your health and symptoms, doing a physical examination, and perhaps giving you tests. Your doctor:
- Will ask if anything triggers the fast heart rate, how long it lasts, if it starts and stops suddenly, and if the beats are regular or irregular.
- May do a test called an electrocardiogram (EKG, ECG). This test measures the heart's electrical activity and can record SVT episodes.
If you do not have an episode of SVT while you're at the doctor's office, your doctor probably will ask you to wear a portable electrocardiogram (EKG), also called an ambulatory electrocardiogram. When you have an episode, the device will record it.
Your doctor also may do tests to find the cause of the SVT. These may include blood tests, a chest X-ray, and an echocardiogram, which shows the heart in motion.
How is it treated?
Some SVTs don't cause symptoms, and you may not need treatment. If you do have symptoms, your doctor probably will recommend treatment.
To treat sudden episodes of SVT, your doctor may:
- Prescribe a medicine to take when the SVT occurs.
- Show you how you can slow your heart rate on your own with physical actions. These actions are called vagal manoeuvres. They include bearing down or putting an ice-cold, wet towel on your face. Bearing down means that you try to breathe out with your stomach muscles but you don't let air out of your nose or mouth. Your doctor might recommend that you do these actions while lying down on your back.
If these treatments don't work, you may have to go to your doctor's office or the emergency room. You may get a fast-acting medicine to slow your heart rate. If the SVT is serious, you may have electrical cardioversion, which uses an electrical current to reset the heart rhythm.
The goals of treatment are to prevent episodes, relieve symptoms, and prevent future problems. You and your doctor can decide what type of treatment is right for you. Your options may include:
- Take medicine every day to prevent the episodes or slow your heart rate.
- Try catheter ablation. This procedure destroys a tiny part of the heart that causes the problem.
What can you do at home to prevent SVT?
You can try some things at home to help prevent SVT by avoiding the things that trigger it.
- Limit or do not drink alcohol.
- Don't smoke.
- Avoid over-the-counter decongestants, herbal remedies, diet pills, and "pep" pills.
- Don't use illegal drugs, such as cocaine, ecstasy, or methamphetamine.
To find your triggers, keep a diary of your heart rate and your symptoms. You might find, for example, that smoking or alcohol causes your SVT episodes.
For most people, moderate amounts of caffeine do not trigger SVT. So most people do not have to avoid chocolate or caffeinated coffee, tea, or soft drinks.
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Two common types of supraventricular tachycardia—atrioventricular reciprocating tachycardia (AVRT) and atrioventricular nodal re-entrant tachycardia (AVNRT)—are caused by an abnormal electrical pathway in the heart and often occur in people who do not have any other type of heart disease. What causes this abnormal pathway might not be clear.
Some experts believe that AVRT—specifically Wolff-Parkinson-White syndrome—may in some cases be inherited.
For more information about how SVT happens, see the topic Types of Supraventricular Tachycardia.
Other types of supraventricular tachycardia may be caused by:
- Overly high levels of the heart medicine digoxin (such as Lanoxin) or the bronchodilator theophylline.
- Other serious health problems, such as chronic obstructive pulmonary disease, heart failure, pneumonia, or metabolic problems.
- Heart surgery in the upper chambers of the heart, such as surgery for a congenital heart defect.
Symptoms of supraventricular tachycardia include:
- A racing or fluttering feeling in the chest (palpitations).
- Chest discomfort (pressure, tightness, pain).
- Light-headedness or dizziness.
- Fainting (syncope).
- Shortness of breath.
- A pounding pulse. You may feel or see your pulse beating, especially at your neck, where large blood vessels are close to the skin.
- Tightness or fullness in the throat.
- Tiredness (fatigue).
- Excessive urine production.
What Increases Your Risk
Some lifestyle factors can raise your risk of having an episode of supraventricular tachycardia, such as overuse of nicotine or alcohol, or use of illegal drugs, such as stimulants like cocaine or methamphetamine.
Decongestants that contain stimulants should also be avoided, including oxymetazoline (such as Dristan and other brands) and pseudoephedrine (such as Sudafed and other brands). Doctors also warn against using non-prescription diet pills or "pep" pills, because many contain ephedra, ephedrine, the herb ma huang, or other stimulants.
Congenital heart defects can raise the risk of having supraventricular tachycardia. Conditions that affect the lungs, such as chronic obstructive pulmonary disease (COPD), pneumonia, heart failure, and pulmonary embolism, can raise your risk for multifocal atrial tachycardia (MAT), a type of supraventricular tachycardia.
Many experts believe that Wolff-Parkinson-White syndrome may in some cases be inherited. If you have a first-degree relative, which is a parent, brother, or sister, with this disorder and he or she has symptoms, talk with your doctor about your risk for this abnormal heart rhythm.
When to Call a Doctor
or seek emergency services immediately if you have a fast heart rate and you:
- Faint or feel as though you are going to faint.
- Have severe shortness of breath.
- Have chest pain.
- Have symptoms of a heart attack or stroke.
Call your doctor if you feel fluttering in your chest (palpitations) that persists and doesn't go away quickly or if you have frequent palpitations.
If you have a pacemaker
Call your doctor right away if you have symptoms that could mean your device is not working properly, such as:
- Your heartbeat is very fast or slow, skipping, or fluttering.
- You feel dizzy, light-headed, or faint.
- You have shortness of breath that is new or getting worse.
Examinations and Tests
An exact diagnosis is important because the treatment you receive depends on the type of tachycardia you have. Supraventricular tachycardia can sometimes be diagnosed simply on the basis of a medical history and physical examination and a few simple tests. Tests that may be done to monitor your heart and diagnose the type of fast heart rate that you have include:
- Electrocardiogram (EKG, ECG), which measures the electrical impulses in the heart. If an electrocardiogram is done while the fast heart rate is occurring, it often provides the most useful information.
- Ambulatory electrocardiogram. A portable EKG, such as a Holter monitor, can record your heart rhythm on a continuous basis, usually over a 24- to 48-hour period. If your symptoms are infrequent, your doctor may use another type of ambulatory electrocardiogram called a cardiac event monitor. When you have symptoms, you activate the monitor, which records your heart rhythm.
- Electrophysiology study. In this test, flexible wires are inserted into a vein, usually in the groin, and threaded into the heart. Electrodes at the end of the wires transmit information about the heart's electrical activity. Your doctor uses this information to see whether there is an extra electrical pathway inside the heart and, if so, where it is located. Catheter ablation can be done during this test to treat abnormal pathways and correct the supraventricular tachycardia.
After finding tachycardia, your doctor may need to search for its cause. The specific tests needed depend on the particular tachycardia. These tests may include:
- Blood tests to check thyroid function and electrolyte levels.
- Chest X-ray and/or pulmonary function tests to check for lung disease.
- Echocardiogram to see how well your heart is working.
Your treatment for supraventricular tachycardia (SVT) depends on a few things. They include what type of SVT, how often you have episodes, and how severe your symptoms are. The goals of treatment are to prevent episodes, relieve symptoms, and prevent problems. You and your doctor can decide what type of treatment is right for you.
Supraventricular tachycardia is usually treated if:
- You have symptoms such as dizziness, chest pain, or fainting (syncope) that are caused by your fast heart rate.
- Your episodes of fast heart rate are occurring more frequently or do not revert to normal on their own.
Treatment for sudden-onset (acute) episodes
When episodes of supraventricular tachycardia (SVT) start suddenly and cause symptoms, you can try vagal manoeuvres. Your doctor will teach you how to do vagal manoeuvres safely. These are things such as bearing down or putting an ice-cold, wet towel on your face.
Your doctor may also prescribe a short-acting medicine that you can take by mouth if vagal manoeuvres don't work. This allows some people to manage their SVT without having to visit the emergency room repeatedly.
If your heart rate cannot be slowed using vagal manoeuvres, you may have to go to your doctor's office or the emergency room, where a fast-acting medicine can be given to slow your heart rate. If the arrhythmia does not stop and symptoms are severe, electrical cardioversion, which uses an electrical current to reset the heart rhythm, may be needed.
Ongoing treatment of recurring supraventricular tachycardia
If you have recurring episodes of supraventricular tachycardia, you may need to take medicines, either on an as-needed basis or daily. Medicine treatment may include beta-blockers, calcium channel blockers, or other antiarrhythmic medicines. In people who have frequent episodes, treatment with medicines can decrease recurrences. But these medicines may have side effects.
Many people with supraventricular tachycardia have a procedure called catheter ablation. This procedure can stop the rhythm problem in most people. Ablation is considered safe, but it has some rare, serious risks.
If supraventricular tachycardia occurs in someone who has significant coronary artery disease, the heart may not receive enough blood to keep up with the demands of the increased heart rate. If this occurs, the heart may not get enough oxygen, potentially causing angina symptoms (such as chest pain or pressure) or a heart attack.
Mild supraventricular tachycardia, with short episodes that don't happen often, doesn't typically weaken the heart or lead to heart failure. But some people have a higher risk of getting heart failure, such as those who have a heart valve disease. If tachycardia is left untreated, repeated and long episodes of tachycardia can lead to heart failure (known as a tachycardia-mediated cardiomyopathy). But this heart failure might be stopped, or reversed, if the supraventricular tachycardia is stopped with treatment.
You can reduce your risk of having episodes of supraventricular tachycardia by avoiding certain stimulants or stressors, such as nicotine, some medicines (for example, decongestants), illegal drugs (stimulants, like methamphetamines and cocaine), and excess alcohol.
If fast heart rates continue, long-term medicines may be used to help prevent a recurrence of the fast heart rate.
Living With Tachycardia
Home care includes monitoring your supraventricular tachycardia and trying to slow your heart when a fast heart rate occurs. To monitor your condition, you may find it helpful to keep a diary of your heart rate and your symptoms.
Your doctor may suggest that you try vagal manoeuvres—such as holding your breath and bearing down, or putting an ice-cold, wet towel on your face—to slow your heart rate. Your doctor will help you learn these procedures so you can try them at home when your fast heart rate occurs.
Check your pulse when you have symptoms, and record the information in your diary. Be aware that if your heart is beating rapidly, it may be hard to feel your pulse and get an accurate count of your actual heart rate.
By keeping a diary of your heart rate and symptoms, you may be able to identify stressors—such as drinking alcohol or smoking—that trigger episodes.
Also, it's usually important to avoid overuse of nicotine or alcohol and the use of illegal drugs, such as stimulants like cocaine, ecstasy, or methamphetamine.
Decongestants that contain stimulants should also be avoided, including oxymetazoline (such as Dristan and other brands) and pseudoephedrine (such as Sudafed and other brands). Doctors also warn against using diet pills or "pep" pills, ephedrine, ephedra, the herb ma huang, or other stimulants.
For most people, moderate amounts of caffeine do not trigger SVT. So most people do not have to avoid chocolate, caffeinated coffee, tea, or soft drinks.
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If you have symptoms, medicines may be used to treat supraventricular tachycardia.
For severe symptoms, such as chest pain, shortness of breath, or feeling faint, you may be given fast-acting antiarrhythmic medicines by health professionals in the hospital emergency department, where your heart can be monitored. Fast-acting antiarrhythmic medicines commonly used to slow the heart rate during an episode include:
- Calcium channel blockers.
Long-term use of an antiarrhythmic medicine may also be needed to reduce the chance of having more episodes of supraventricular tachycardia or to reduce the heart rate during these episodes. Common medicines used for this purpose include:
- Calcium channel blockers.
- Other antiarrhythmic medicines.
Open-heart surgery is rarely done for supraventricular tachycardia. Surgery might be done if you cannot have catheter ablation or if you are having surgery for another heart condition.
An electric shock to the heart (electrical cardioversion) may be needed if you are having severe symptoms of supraventricular tachycardia and your heart rate does not return to normal using vagal manoeuvres or fast-acting medicines.
A procedure called catheter ablation may be done to try to stop SVT. During this procedure, the extra electrical pathway or cells in the heart that are causing the fast heart rate can often be identified and destroyed.
Other treatment choices
Current as of:
January 10, 2022
Author: Healthwise Staff
Rakesh K. Pai MD, FACC - Cardiology, Electrophysiology
Brian D. O'Brien MD - Internal Medicine
E. Gregory Thompson MD - Internal Medicine
Adam Husney MD - Family Medicine
Martin J. Gabica MD - Family Medicine
John M. Miller MD, FACC - Cardiology, Electrophysiology
Current as of: January 10, 2022
Author: Healthwise Staff
Medical Review:Rakesh K. Pai MD, FACC - Cardiology, Electrophysiology & Brian D. O'Brien MD - Internal Medicine & E. Gregory Thompson MD - Internal Medicine & Adam Husney MD - Family Medicine & Martin J. Gabica MD - Family Medicine & John M. Miller MD, FACC - Cardiology, Electrophysiology
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