Supraventricular tachycardia (SVT) is a rapid heart rate (tachycardia) usually caused when electrical impulses originating at or above the atrioventricular node, or AV node (part of the heart's electrical control system which controls rate) are out of synch.
When a person goes into this arrhythmia, the heart beats at least 100 beats per minute and can be as high as 300 beats per minute. SVT is also known as paroxysmal supraventricular tachycardia (PSVT) or paroxysmal atrial tachycardia (PAT).
People with SVT may go into this arrhythmia from time to time unrelated to exercise, stress or other common causes of a rapid heart rate. For most people, SVT is not dangerous. The heart continues to work normally, pumping blood through the body.
SVT Symptoms, Causes and Diagnosis
Some patients with SVT, which generally first arises in people in their teens and 20s, may have no symptoms, going in and out of the arrhythmia quickly. Others have symptoms, such as palpitations, a racing heart, sweating and feeling lightheaded or dizzy. SVT can become a problem requiring treatment if it lasts a long time or causes shortness of breath or chest pain.
Though most episodes of SVT are caused by the heart’s electrical system, other causes include certain drugs, health conditions, surgery and familial disorders, such as Wolff-Parkinson-White syndrome.
SVT can be diagnosed by your doctor through a physical exam and questions about what triggers your fast or irregular heart rate. Tests include X-rays or an electrocardiogram (EKG, ECG) to measure the heart's electrical activity and record SVT events. You may have to temporarily wear a portable EKG to pick up events as they occur.
Treatment and Prevention
Treatments for SVT include medications you can take at the onset of symptoms, and “vagal maneuvers” which allow you to slow your heart rate yourself through coughing, gagging or putting your face in cold water. Another maneuver can be described as blowing into your fist as if it is a trumpet mouthpiece.
If you cannot resolve the SVT on your own, you may need to see your doctor or go to the ER for a fast-acting medication or even electrical cardioversion, a procedure that uses an electric current to reset the heart's rhythm.
To manage SVT on a regular basis there are medicines to slow the heart rate and prevent the onset of SVT. However, for more stubborn cases, there is a procedure called catheter ablation, which destroys the part of the heart that causes the problem. This procedure is the gold standard and has a 99 percent success rate. We do this procedure more than any other ablation.
There are ways to prevent SVT at home by avoiding certain triggers. Common triggers include alcohol, caffeine, smoking, some over-the-counter decongestants, diet pills, and drugs such as cocaine and methamphetamine.
Make an Appointment
The Arrhythmia Program at the University of Michigan has been a national and international leader in the treatment of arrhythmias for more than 30 years. To schedule an appointment to discuss your heart arrhythmia or other cardiovascular condition, call us at 888-287-1082 or visit our Make a Cardiovascular Appointment page, where you may fill out a Patient Appointment Request Form and view other details about making an appointment.