Cardinal Features and Treatment
The presence of the following features may suggest a supraventricular origin of a BCT:
- Age <35 years
- Rate =150 bpm
- Rate >200 bpm and patient asymptomatic
- QRS duration <0.14 seconds
- Axis normal
- Absence of independent atrial activity or concordance
Treatment
Vagal manoeuvres and adenosine (a short-acting purine) may be used diagnostically (to help identify BCT which is supraventricular in origin) and therapeutically (to terminate the arrhythmia). The ECG shows atrial flutter and left bundle branch block. Click on the image to enlarge.
Refer to the Supraventricular Tachycardia Learning Session for more information on detailed management of SVT.
A BCT should be assumed to be ventricular in origin unless there are specific features supporting a supraventricular origin.