From the Guidelines
No, supraventricular tachycardia (SVT) is not a ventricular rhythm.
Definition of SVT
SVT is defined as an umbrella term used to describe tachycardias (atrial and/or ventricular rates in excess of 100 bpm at rest), the mechanism of which involves tissue from the His bundle or above 1.
Key Characteristics
The key characteristics of SVT include:
- Atrial and/or ventricular rates >100 b.p.m. at rest
- Initiation and sustenance of the arrhythmia requires atrial and/or atrioventricular nodal tissues
- SVTs usually start/stop abruptly and are rarely life-threatening
- Common symptoms include palpitations, chest discomfort, fatigue, light-headedness, shortness of breath, anxiety, dizziness, dyspnoea, and, uncommonly, syncope
Differentiation from Ventricular Tachycardia
SVT can be differentiated from ventricular tachycardia (VT) using ECG criteria, such as:
- Presence of AV dissociation or fusion complexes, which suggests VT
- QRS complex morphology in the precordial leads, which can indicate VT or SVT
- Presence of a P wave with a morphology that differs from sinus, which is typically seen in SVT
- RP interval, which is typically short in AVNRT and AVRT, and long in AT 1.
Clinical Implications
In clinical practice, it is essential to accurately diagnose SVT and differentiate it from VT, as the management and treatment of these conditions differ significantly. A 12-lead ECG obtained during tachycardia and during sinus rhythm can help reveal the etiology of the tachycardia and guide treatment decisions 1.
From the Research
Definition of Supraventricular Tachycardia (SVT)
- SVT is an abnormal rapid cardiac rhythm that involves atrial or atrioventricular node tissue from the His bundle or above 2
- It originates above the bifurcation of the bundle of His 3
Differentiation from Ventricular Tachycardia
- SVT can be distinguished from ventricular tachycardia in more than 90% of tachycardias using a systematic approach to the 12-lead ECG 4
- The differentiation between supraventricular and ventricular tachycardias usually requires an assessment of atrial and ventricular rhythms and their relationship to each other 5
- A wide QRS tachycardia should be treated as ventricular tachycardias unless proven to be an SVT with aberration 6