SVT stands for Supraventricular Tachycardia. A Tachycardia means fast heartbeat. Supraventricular means it originates from somewhere above the ventricles i.e. in the atria or top chambers of the heart.
SVT usually refers to regular fast heart rhythms, as opposed to AF (which is technically still an SVT), which is irregular. This classification is useful, as SVTs are usually benign as opposed to heart rhythm disorders from the ventricles, which are not always.
There are three main types of SVT:
- Atrioventricular reentrant tachycardia (AVRT) – (also known as orthodromic reentrant tachycardia (ORT), or antidromic tachycardia depending on which direction it travels)
- Atrioventricular nodal reentrant tachycardia (AVNRT)
- Atrial tachycardia
SVTs are common in young people, particularly AVRT, which is most often seen in children and adolescents. AVNRT and atrial tachycardia are more often seen in middle-aged or elderly people. They are all due to a single abnormal electrical short circuit within the heart or from an abnormal focus of electricity.