Supraventricular Tachycardia

Abstract

Supraventricular tachycardia (SVT) is typically a regular, narrow complex tachyarrhythmia. It is often caused by a reentrant mechanism between the atria and ventricles but can also be caused by enhanced automaticity in the atria or AV node. Atrioventricular nodal reentrant tachycardia (AVNRT) is the most common type of SVT, followed by atrioventricular reentrant tachycardia (AVRT) and atrial tachycardia (AT), although incidence can vary based on age. When SVT is suspected, a 12-lead ECG should first be obtained. The RP interval, among other features, can aid in diagnosis of the particular type of SVT. Short RP tachycardias include typical AVNRT, most AVRT, and some ATs. Long RP tachycardias include other forms of AT, atypical AVNRT, and, rarely, AVRT. Vagal maneuvers such as the Valsalva and modified Valsalva should be considered and taught to patients to use in cases of hemodynamically stable SVT. If SVT remains refractory to vagal maneuvers, adenosine and electrical cardioversion can be considered in the inpatient setting. Here, we review the incidence and prevalence of SVT prior to discussing ECG features, diagnosis, and management of its various subtypes. We then suggest an approach to diagnosing patients with suspected SVT.