Paroxysmal Supraventricular Tachycardia (PSVT)

What is paroxysmal supraventricular tachycardia (PSVT)?

Tachycardia is a very fast heart rate, usually faster than 150 beats per minute. Paroxysmal supraventricular tachycardia (PSVT) is a fast heart rate that comes and goes.

PSVT can start at any age, but it is most common in people in their 20s and 30s. It is more common in women than in men. It may happen more often during pregnancy.

How does it occur?

An electrical signal in your heart causes it to pump. Normally, this signal starts in the right upper chamber of the heart (the right atrium). Then it moves along a pathway to the lower chambers of the heart (the ventricles).

Normally there is one electrical pathway from the atrium to the ventricles. People with PSVT almost always have an extra electrical pathway connecting the upper and lower chambers. When the electrical signal goes down both pathways at the same time, the heart can beat normally. If the electrical signal goes down the normal pathway faster and then goes back up the extra pathway, the heart beats very fast.

What are the symptoms?

Symptoms of PSVT may be mild or severe. You may feel a rapid heartbeat or palpitations. Palpitations are feelings of strong heartbeats in your chest or throat. You may feel weak, dizzy, or lightheaded. You may faint.

How is it diagnosed?

Your healthcare provider will ask about your medical history, including your symptoms. He or she will examine your heart and lungs. You may have blood tests to check for diseases such as thyroid disease. You may have a chest X-ray. You will have an electrocardiogram (ECG), which measures the electrical activity of your heart.

If you are not having symptoms when an ECG is done in your provider's office, your provider may not see the activity pattern caused by PSVT. You may have to wear a Holter monitor or event recorder to record your heart rate. The Holter monitor is a portable ECG used to detect heart rhythm problems.

A study of the electrical path of your heart, called an electrophysiologic study (EPS), can also help locate the source of abnormal heart rhythms.

How is it treated?

PSVT is rarely life threatening. You may not need treatment if the attacks are rare, do not last long, and do not cause serious symptoms.

Ways you can help stop an attack of PSVT are:

• Put pressure over an artery in your neck (carotid artery) at the angle of the jaw for 3 to 5 seconds.
• Take a deep breath, hold it, and strain for 3 to 5 seconds.

Both of these actions send nerve signals to the heart to slow the electrical signal enough to slow down the heart rate back to normal. Once your healthcare provider shows you these methods, you may be able to do them on your own.

If you have frequent attacks of PSVT and the attacks last a long time, your provider may prescribe drugs that slow the movement of electrical signals from the atrium to the ventricles. Types of medicines that may be used for this are calcium channel blockers, digoxin, beta blockers, and antiarrhythmic medicines.

Your provider may suggest cardiac ablation, especially if medicine does not stop the attacks. This procedure delivers radio wave energy to the inside of the heart. It blocks abnormal electrical pathways in the heart and helps stop abnormal heart rhythms. It usually provides lasting relief from PSVT and often is the treatment of choice.

How long will the effects last?

Without ablation, you may keep having attacks of PSVT.

If the attacks happen often and last a long time, the heart muscle can get weak. A weak heart does not pump as well as it should. Cardiac ablation will stop the attacks of PSVT so your heart is not weakened more by this problem.

How can I take care of myself?

• Follow the treatment recommended by your healthcare provider.
• If you have a spell of PSVT and the recommended treatments do not work after 15 to 30 minutes, call your healthcare provider. If you have severe weakness, call right away. If you are feeling faint or fainting, you should not drive. Instead, call 911 for an ambulance to take you to the emergency room.

How can I help prevent PSVT?

The best prevention is to have a heart-healthy lifestyle. There is no guarantee that you will never have PSVT, but these suggestions may reduce the number of attacks. To be heart healthy:

• Maintain a healthy weight.
• Eat a healthy diet.
• Get regular exercise, as recommended by your healthcare provider.
• Do not smoke.
• Limit your use of alcohol.