6th March 2024

Atrioventricular nodal reentry tachycardia (AVNRT)

AVNRT occurs due to two (fast and slow) pathways within the AV node. These pathways have varying refractory periods which allow for a re-entry tachycardia to arise. The ECG will show a regular narrow complex tachycardia with no discernible p waves and pseudo-R’ waves in V1/V2, characteristic of retrograde conducted p waves.

Patients may describe transient episodes of palpitations that are well tolerated. The arrhythmia is managed by creating a temporary block in the AV node to interrupt the re-entry circuit and can be achieved by vagal manoeuvres; adenosine or verapamil if adenosine is contraindicated (e.g., asthmatic patients). Medical prophylaxis includes beta-blockers, verapamil or digoxin and curative treatment involves radiofrequency ablation. In those with refractory AVNRT Amiodarone may be used.