Supraventricular tachycardia (SVT) is an abnormal fast heart rhythm that starts in the upper chambers, or the atria, of the heart. Normally, the heart's electrical system controls the rhythm and rate of heart beats. In supraventricular tachycardia, abnormal electrical function causes the heart to beat too fast. During supraventricular tachycardia episodes, the heart beats faster than 100 beats per minute and can even reach 300 beats per minute.
Although the condition is present at birth, symptoms of Wolff-Parkinson-White syndrome may not occur until the teens or early 20s. Many people with the condition may never experience symptoms, or, they may occur very rarely. When they do occur, symptoms can include:
- Rapid heart beat
- Chest pain
- Difficulty breathing
Most supraventricular tachycardia results from abnormal electrical connections in the heart, although what causes these abnormalities often isn’t clear. In the case of Wolff-Parkinson-White syndrome, the condition may be inherited. And, some medications can cause SVT.
Tests that are commonly used to evaluate the presence of supraventricular tachycardia include an electrocardiogram to measure the heart’s electrical activity and Holter monitoring (a portable EKG that is worn for 24 hours) to track the heart’s activity during that period. An electrophysiology study may also be conducted.
Some patients are able to use techniques such as coughing or the Valsalva maneuver, a breathing exercise, to control supraventricular tachycardia. Medications may also be prescribed to slow the heart rate.
In some cases, catheter ablation may be used to destroy selected portions of the heart muscle in order to stop the supraventricular tachycardia from occurring.