• Supraventricular tachycardia (SVT) is any tachyarrhythmia from above ("supra") the ventricles as opposed to within the ventricles in ventricular tachycardia (VT).
• When there is a block (or aberrancy) in the conduction pathway to the ventricles (either a bundle branch block or intraventricular conduction delay) or preexcitation, SVT will be associated with widened QRS complexes and the resulting rhythm can be difficult to distinguish from monomorphic VT.
• Though difficult, VT can be differentiated from SVT with aberrancy based on patient's history and certain ECG features listed below.
• Certain algorithms can be used to differentiate VT from SVT with aberrancy such as Brugada or Vereckei criteria.
• Age > 35
• Hx of structural heart disease
• Family hx of sudden cardiac death
• Unresponsive to AV blockade
• ECG features
1 Extreme NW axis
2 Concordance
3 AV dissociation
4 Capture or fusion beats
5 Atypical BBB morphology
6 QRS > 160ms
7 RS > 100ms (Brugada criteria)
8 RWPT ≥ 50ms
9 Initial R in aVR (Vereckei criteria)
10 Slow initial activation (Vereckei)
• Age < 35
• No structural heart disease
• No family hx of sudden cardiac death
• Sensitive to AV blockade
• ECG features
1 Non-extreme axis
2 No concordance
3 AV association
4 No capture or fusion beats
5 Typical BBB morphology
6 QRS < 140ms
7 RS < 100ms RS (Brugada criteria)
8 RWPT < 50ms
9 No initial R in aVR (Vereckei criteria)
10 Rapid initial activation (Vereckei)
