What Is Supraventricular Tachycardia (SVT)?

Supraventricular tachycardia (SVT) is a broad term for a group of rapid heart rhythm disorders that originate above the ventricles — in the atria, the AV node, or the tissue connecting atria and ventricles. SVT causes sudden-onset episodes of rapid, usually regular heartbeat — often beginning and ending abruptly — that can cause palpitations, breathlessness, lightheadedness, and anxiety. While SVT is rarely life-threatening in people with otherwise normal hearts, it can be frightening, disabling, and in some forms carry specific risks that warrant treatment.

WHAT MAKES A TACHYCARDIA "SUPRAVENTRICULAR"?

The term "supraventricular" literally means "above the ventricles." SVTs involve electrical circuits or ectopic foci located in the atria or AV junction — above the His bundle. The electrical activation still reaches the ventricles through the normal conduction system, so the QRS complex on ECG is typically narrow (normal width) — distinguishing SVT from ventricular tachycardia (VT), which has a wide QRS because it originates in the ventricles.

The Major Types Of Svt