Supraventricular Tachycardia

Topic Overview

Atrial fibrillation is the most common type of supraventricular tachycardia. For information on this condition, see the topic Atrial Fibrillation. If you have ventricular tachycardia, see the topic Ventricular Tachycardia.

What is supraventricular tachycardia?

Supraventricular tachycardia (SVT) is an abnormal fast heart rhythm that starts in the upper chambers, or the atria, of the heart. ("Supraventricular" means above the ventricles, "tachy" means fast, and "cardia" means heart.)

Normally, the heart's electrical system precisely controls the rhythm and rate at which the heart beats. In supraventricular tachycardia, abnormal electrical connections (or abnormal firing of the connections) cause the heart to beat too fast. Typically, during supraventricular tachycardia episodes, the heart beats faster than 100 beats per minute. Sometimes the heart beats as fast as 300 beats per minute. Usually, the heart returns to a normal rate (60 to 100 beats per minute) on its own or after treatment.

Supraventricular tachycardia (SVT) is also called paroxysmal supraventricular tachycardia (PSVT) or paroxysmal atrial tachycardia (PAT).

What are the different types of supraventricular tachycardia?

Sometimes it is normal to have an increased heart rate-for example, during exercise, with a high fever, or when under stress. This fast heart rate, called sinus tachycardia, is a normal response to these stressors and is not considered a medical problem. This topic addresses the types of supraventricular tachycardias that are considered abnormal. These include:

• Atrioventricular nodal reentrant tachycardia (AVNRT), the most common type (after atrial fibrillation).
• Atrioventricular reciprocating tachycardia (AVRT), including Wolff-Parkinson-White syndrome.

What causes supraventricular tachycardia?

Most supraventricular tachycardia results from abnormal electrical connections in the heart that short-circuit the normal electrical system. What causes these abnormal pathways is not clear. In the case of Wolff-Parkinson-White syndrome, the condition may be inherited.

Some medicines can cause supraventricular tachycardia. Overly high levels of the heart medicine digoxin (such as Lanoxicaps or Lanoxin) can cause some types of supraventricular tachycardia (such as Wolff-Parkinson-White syndrome) to get worse. But digoxin may be used to treat some other types of SVT (such as atrial fibrillation). The bronchodilator theophylline may also cause tachycardia.

In rare cases, conditions that affect the lungs-such as chronic obstructive pulmonary disease (COPD) or pneumonia-can also cause a type of SVT called multifocal atrial tachycardia (MAT).

What are the symptoms?

With supraventricular tachycardia, you may have palpitations, an uncomfortable feeling that your heart is racing or pounding. You may also notice that your pulse is rapid or see or feel your pulse pounding, especially at your neck, where large arteries are close to the skin. Other symptoms include feeling dizzy or lightheaded, near-fainting or fainting (syncope), shortness of breath, chest pain, throat tightness, and sweating.

How is supraventricular tachycardia diagnosed?

A description of your symptoms is one of the most important clues in diagnosing supraventricular tachycardia. Your doctor will ask what, if anything, triggers the episodes, how long they last, if they start and stop suddenly, whether anything stops them, and whether the beats are regular or irregular.

Because supraventricular tachycardia is a problem with your heart's electrical system, the most important test is an electrocardiogram (EKG, ECG). An EKG measures the heart's electrical activity and can record supraventricular tachycardia episodes. An EKG is usually done along with a medical history and physical examination, lab tests, and a chest X-ray.

If you do not have an episode of supraventricular tachycardia while at the doctor's office, your doctor will probably ask you to wear a portable EKG to record your heart rhythm on a continuous basis. This is referred to by several names, including ambulatory electrocardiogram, ambulatory ECG, Holter monitoring, 24-hour EKG, or cardiac event monitoring. This will allow your heart rhythm to be recorded while you are having supraventricular tachycardia.

Your doctor may also recommend an electrophysiology (EP) 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 send information about the heart's electrical activity. In this way, the EP study can map any abnormal electrical activity, identify the type of supraventricular tachycardia you have, and guide treatment.

How is it treated?

Some supraventricular tachycardias do not cause symptoms and may not need treatment. But when symptoms occur, treatment is usually recommended.

Your doctor may teach you how to perform vagal maneuvers, such as the Valsalva maneuver or coughing, to slow your heart rate. If vagal maneuvers do not work, a fast-acting intravenous (IV) medicine such as adenosine or verapamil can be given. If the arrhythmia does not stop and symptoms are severe, electrical cardioversion, in which a brief electric shock is given to the heart to reset the heart rhythm, may be needed.

If supraventricular tachycardia recurs, you may need long-term treatment, including:

• Beta-blockers or other antiarrhythmic medicines to prevent an episode or to slow the heart rate.
• Catheter ablation, which is usually done during an electrophysiology (EP) study. The most common type of catheter ablation uses radio waves (radiofrequency energy). These waves are directed through the catheter to the specific heart tissue that is generating abnormal electrical impulses. The radio waves cause the area of the heart muscle to be heated and selectively destroyed, eliminating the SVT.

What precautions should I take?

Avoid consuming large amounts of alcohol or caffeine, either of which may provoke episodes of supraventricular tachycardia. Also, nonprescription decongestants, herbal remedies, diet pills, and "pep" pills often contain stimulants and should be avoided. Illegal drugs, such as stimulants like cocaine, ecstasy, or methamphetamine, also can trigger episodes. It is important to be aware of which substances have an effect on you and to avoid them.

Frequently Asked Questions

Cause

Two common types of supraventricular tachycardia-atrioventricular reciprocating tachycardia (AVRT) and atrioventricular nodal reentrant 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 is not clear.

Some experts believe that AVRT-specifically Wolff-Parkinson-White syndrome-may in some cases be inherited.

Other types of supraventricular tachycardia may be caused by:

• Atrial cells firing off signals rapidly (called atrial tachycardia). Atrial tachycardia is seen most often in people with structural heart disease.
• Overly high levels of the heart medicine digoxin (such as Lanoxicaps or Lanoxin) or the bronchodilator theophylline (such as Bronkodyl, Elixophyllin, Slo-Bid, Slo-Phyllin, or Theo-Dur).
• Other serious health problems, such as chronic obstructive pulmonary disease, heart failure, pneumonia, or metabolic problems.

Symptoms

Symptoms of supraventricular tachycardia include:

• A racing or fluttering feeling in the chest (palpitations).
• Chest discomfort (pressure, tightness, pain).
• Lightheadedness 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.
• Sweating.
• 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 caffeine, 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 Afrin and other brands) and pseudoephedrine (such as Sudafed and other brands). Doctors also warn against using nonprescription diet pills or "pep" pills, because many contain caffeine, ephedra, ephedrine, the herb ma huang, or other stimulants.

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 of developing this abnormal heart rhythm.

When to Call a Doctor

Call 911 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 are having fluttering in your chest (palpitations) that persists and does not go away quickly or if you have frequent palpitations.

Watchful Waiting

If you have a fast heart rate and you have symptoms that may be caused by the fast heart rate, watchful waiting is not appropriate. See your doctor.

Who to See

Health professionals who can evaluate symptoms of a fast or irregular heartbeat include:

• Family medicine doctors.
• Internists.
• Cardiologists.
• Electrophysiologists.
• Nurse practitioners (NPs).
• Physician assistants (PAs).

Most people with supraventricular tachycardia need to see a cardiologist or electrophysiologist for follow-up care.

Exams 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. The physical exam may include a carotid sinus massage. 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 performed 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-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. This information is used to determine 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.
• Medicine trial. Giving certain medicines while you are experiencing a fast heart rate, and monitoring what happens, may sometimes help your doctor determine what type of fast heart rate problem you have.

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 look at your heart.

Treatment Overview

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 maneuvers-such as gagging, holding your breath and bearing down (Valsalva maneuver), immersing your face in ice-cold water (diving reflex), coughing, or putting pressure on your eyelids. These simple maneuvers stimulate the vagus nerve, which can slow conduction of electrical impulses that control your heart rate. Your doctor will teach you how to perform vagal maneuvers safely.

Your doctor may also prescribe a short-acting medicine that you can take by mouth if vagal maneuvers 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 maneuvers, you may have to go to your doctor's office or the emergency room, where a fast-acting medicine such as adenosine or verapamil can be given. 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 typically includes beta-blockers, calcium channel blockers, other antiarrhythmic medicines, or digoxin. In people with 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, which blocks abnormal electric impulses and can eliminate supraventricular tachycardia and the need to take medicines. But this procedure has risks, including infection, bleeding, and injury to the heart. If your heart is injured during catheter ablation, you will need a pacemaker. You must balance your feelings about taking medicine for the rest of your life with having an invasive procedure. Also, catheter ablation is not available everywhere and is best performed in a medical center that has staff experienced with this complicated procedure.

Treatment for atrioventricular nodal reentrant tachycardia (AVNRT)

In the case of atrioventricular nodal reentrant tachycardia (AVNRT), medicines can be taken-either daily or only when the fast heartbeat arises-or catheter ablation may be done.

If you have infrequent episodes of AVNRT that last hours but do not cause severe symptoms, your doctor may recommend that you take medicines only when you have an episode. These medicines include antiarrhythmic medicines, calcium channel blockers, and beta-blockers.

Your doctors may recommend daily doses of calcium channel blockers, beta-blockers, and/or digoxin if you have frequent episodes of AVNRT. If these medicines are not effective in stopping supraventricular tachycardia from recurring, your doctor may recommend that you take an antiarrhythmic medicine.

If you take daily medicine for AVNRT or you have significant symptoms, you may want to consider having catheter ablation.

Treatment for atrioventricular reciprocating tachycardia (AVRT)

In the case of atrioventricular reciprocating tachycardia (AVRT), you can take medicines for recurrent episodes either on an as-needed or daily basis, depending on how frequently they occur. These medicines-which include beta-blockers, calcium channel blockers, and digoxin-are often effective in stopping or preventing episodes of AVRT.

But in some people with a type of AVRT called Wolff-Parkinson-White (WPW) syndrome, digoxin and verapamil may result in extremely fast heart rates that can lead to lightheadedness, fainting (syncope), and even death. These drugs are only dangerous when given in an emergency when someone with Wolff-Parkinson-White syndrome is having atrial fibrillation.

Treatment of WPW frequently requires antiarrhythmic medicines, such as propafenone (Rythmol) or flecainide (Tambocor), that slow electrical conduction over the extra connection.

Catheter ablation is often recommended for people with WPW, especially those who have severe symptoms or also have atrial fibrillation or flutter. This procedure can successfully eliminate WPW most of the time. There is a small risk of the arrhythmia recurring even after successful ablation of WPW. But a second session of catheter ablation is usually successful.

Ongoing Concerns

Symptoms of atrioventricular reciprocating tachycardia (AVRT), including Wolff-Parkinson-White (WPW) syndrome, usually start during the teen or young adult years. Episodes of WPW can trigger a life-threatening heart rhythm called ventricular fibrillation, although this is extremely rare. Your doctor may recommend that you wear a medical bracelet to alert medical professionals of your condition if you are at risk for ventricular fibrillation.

AV nodal reentrant tachycardia (AVNRT) usually first causes symptoms from the teen years to middle age.

After episodes of supraventricular tachycardia begin, they generally recur. These arrhythmias frequently stop spontaneously or with simple maneuvers, but you may have to take medicines daily if the arrhythmias keep happening. Medicine treatment typically includes beta-blockers, calcium channel blockers, or digoxin. In people with frequent episodes, treatment with an antiarrhythmic medicine can decrease recurrences, and catheter ablation can eliminate the arrhythmia altogether.

When supraventricular tachycardia occurs in someone with 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 chest pain (angina) or a heart attack. If tachycardia is left untreated, repeated and long episodes of tachycardia can lead to heart failure. But mild supraventricular tachycardia, with rare and short episodes, does not typically lead to heart failure.

Prevention

You can reduce your risk of having episodes of supraventricular tachycardia by avoiding certain stimulants or stressors, such as caffeine, nicotine, some medicines (for example, decongestants), illegal drugs (stimulants, like methamphetamines and cocaine), excess alcohol, lack of sleep, and overeating.

If fast heart rates continue, long-term medicines such as beta-blockers 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.

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 difficult 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 lack of sleep, drinking alcohol, or overeating-that trigger episodes.

Also, it's usually important to avoid overuse of caffeine, nicotine, or alcohol and the use of illegal drugs, such as stimulants like cocaine, ecstasy, or methamphetamine. For people who are especially sensitive, even decaffeinated teas or coffee can cause supraventricular tachycardia episodes.

Decongestants that contain stimulants should also be avoided, including oxymetazoline (such as Afrin and other brands) and pseudoephedrine (such as Sudafed and other brands). Doctors also warn against using diet pills or "pep" pills (because many contain caffeine), ephedrine, ephedra, the herb ma huang, or other stimulants.

Your doctor may suggest that you try vagal maneuvers-such as gagging, holding your breath and bearing down, or immersing your face in cold water-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.

Medications

If you have symptoms, medicines may be used to treat supraventricular tachycardia.

Medication Choices

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:

• Adenosine.
• Calcium channel blockers(specifically verapamil and diltiazem).
• Beta-blockers (specifically propranolol, metoprolol, or esmolol).

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:

• Beta-blockers.
• Calcium channel blockers.
• Digoxin.
• Other antiarrhythmic medicines.

What to Think About

All medicines have side effects. See a table of medicines that may interact with other medicines and with pacemakers and implantable cardioverter defibrillators (ICDs).

Surgery

Open-heart surgery for supraventricular tachycardia is performed rarely and is usually done only if surgery to remove abnormal electrical pathways (catheter ablation) or other treatments cannot be used. If you have heart surgery for another heart condition, catheter ablation may be done at the same time.

Other Treatment

An electric shock to the heart (electrical cardioversion) may be necessary if you are having severe symptoms of supraventricular tachycardia and your heart rate does not return to normal using vagal maneuvers or fast-acting medicines.

If you continue to have episodes that cause serious symptoms, a procedure called catheter ablation may be done during an electrophysiology (EP) study. During an EP study, the extra electrical pathway or cells in the heart that are causing the fast heart rate can often be identified and destroyed using catheter ablation.

If you have tried other treatment, such as medicine and catheter ablation, but still have tachycardia, a pacemaker might be an option.

Other Treatment Choices

Electrical cardioversion

Catheter ablation

Pacemaker

What to think about

Electrical cardioversion is only used in an emergency. If you are awake, medicines will be used to control pain and make you sleepy during the procedure.

Catheter ablation is effective for people with severely symptomatic supraventricular tachycardia due to AV nodal reentrant tachycardia or a concealed bypass tract. It can also reduce medical costs when compared with commonly used drug therapies.

Catheter ablation has risks, but they are rare. You must balance your feelings about taking medicine for the rest of your life with having an invasive procedure.

A pacemaker might be an option for some people. Your doctor may suggest a pacemaker if you have symptoms and if medicine or catheter ablation have not worked for you.

Other Places To Get Help

Organizations

Related Information

• Anxiety
• Atrial Fibrillation
• Bradycardia (Slow Heart Rate)
• Change in Heartbeat
• Chest Pain

References

Other Works Consulted

• Calkins H (2008). Supraventricular tachycardia: AV nodal reentry and Wolff-Parkinson-White syndrome. In V Fuster et al., eds., Hurst's The Heart, 12th ed., pp. 983-1002. New York: McGraw-Hill Medical.

• Drugs for cardiac arrhythmias (2007). Treatment Guidelines From The Medical Letter, 5(58): 51-58.

• Epstein AE, et al. (2008). ACC/AHA/HRS 2008 Guidelines for Device-Based Therapy of Cardiac Rhythm Abnormalities: A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Writing Committee to Revise the ACC/AHA/NASPE 2002 Guideline Update for Implantation of Cardiac Pacemakers and Antiarrhythmia Devices): Developed in Collaboration With the American Association for Thoracic Surgery and Society of Thoracic Surgeons. Circulation, 117(21): e350-e408.

• Olgin JE, Zipes DP (2008). Specific arrhythmias: Diagnosis and treatment. In P Libby et al., eds., Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine, 8th ed., volume 1, pp. 863-931. Philadelphia: Saunders Elsevier.

• U.S. Food and Drug Administration (2005). 2005 safety alert: Cordarone (amiodarone HCl). FDA Med Watch. Available online: http://www.fda.gov/medwatch/SAFETY/2005/cordarone_DHCP.htm.

• Zipes DP, et al. (2006). ACC/AHA/ESC 2006 Guidelines for Management of Patients With Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death: A Report of the American College of Cardiology/American Heart Association Task Force and the European Society of Cardiology Committee for Practice Guidelines (Writing Committee to Develop Guidelines for Management of Patients With Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death). Circulation, 114(10): 1088-1032.

Credits