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:
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 also is called 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:
How is SVT diagnosed?
Your doctor will diagnose SVT by asking you questions about your health and symptoms, doing a physical exam, and perhaps giving you tests. Your doctor:
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.
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:
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 such as adenosine or verapamil. If the SVT is serious, you may have electrical cardioversion, which uses an electrical current to reset the heart rhythm.
If you often have episodes of SVT, you may need to:
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.
To find your triggers, keep a diary of your heart rate and your symptoms. You might find, for example, that smoking or caffeine causes your SVT episodes.
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