An arrhythmia caused by a second connection between atria and ventricles, in addition to the normal conduction system. There are two types:
- AVRNT (Atrio-Ventricular Node Re-entry Tachycardia) - the second connection is closely related to the AV node.
- AVRT (Atrio-Ventricular Re-entry Tachycardia) - the second connection is not related to the AV node.
Symptoms can be associated with exertion
Rate of 130-250. Narrow QRS complex (except in bundle branch block), P waves are: inverted, masked by QRS complex (AVNRT) or occur halfway between complexes (AVRT), one P wave per QRS complex.
- Drugs - adenosine or verapamil. (Flecanide, sotalol, dispyramide are other options).
- Electrical - pacing and cardioversion as above.
- Vagal - carotid sinus massage, pressure on closed eyes, application of ice to face.
- Ablation - burning away the dodgy bit of conduction pathway.