Supraventricular Tachycardia (SVT)
A supraventricular arrhythmias is tachycardia (fast heart rate) that starts in the atria or the atrioventricular (AV) node. The AV node is a group of cells located between the atria and the ventricles.
Paroxysmal Supraventricular Tachycardia
PSVT is a tachycardia with a very fast heart rate that begins and ends suddenly. PSVT occurs due to problems with the electrical connection between the atria and the ventricles.
In PSVT, electrical signals that begin in the atria and travel to the ventricles can reenter the atria, causing extra heartbeats. This type of arrhythmia usually isn't dangerous and tends to occur in young people. It can happen during vigorous exercise.
A special type of PSVT is called Wolff-Parkinson-White syndrome. WPW syndrome is a condition in which the heart's electrical signals travel along an extra pathway from the atria to the ventricles.
This extra pathway disrupts the timing of the heart's electrical signals and can cause the ventricles to beat very fast. This type of arrhythmia can be life threatening.