|This is part of: Supraventricular Rhythms|
An AV Nodal Re-entry Tachycardia (AVNRT) is a rapid tachycardia with a typical frequency around 200 bpm. The tachycardia origin is the AV node. A prerequisite for AVNRT is a slow and fast pathway in the AV node, most often caused by degradation of the AV nodular tissue. The dual pathways facilitate re-entry.
Two sensitive characteristics to identify AVNRT on the ECG are:
- R'. This is a small secondary R wave. It resembles a right bundel branch block, but the QRS width stays < 120ms.
- RP << 100ms. The distance between the R and P waves is less than 100ms.