Normally, the heart's electrical system precisely controls the rhythm and rate at which the heart beats. In Supraventricular Tachycardia SVT, abnormal electrical signals (or abnormal firing of the connections) cause the heart to beat at a rate of greater than 100 beats per minute and may get as high as 300 beats per minute.  Most often the heart may return to a normal rate (60 to 100 beats per minute) on its own, however, seek medical treatment immediately if the heart rate does not return to normal.

Treatment of SVT varies significantly from patient to patient and is based on the frequency, duration, type, and severity of symptoms.  The goal of the treatment is to prevent episodes and problems and to relieve symptoms.