| AV-nodal reentrant tachycardia | |
|---|---|
| Other names | Atrioventricular-nodal reentrant tachycardia |
 | |
| An example of an ECG tracing typical of uncommon AV nodal reentrant tachycardia. Highlighted in yellow is the P wave that falls after the QRS complex. | |
| Specialty | Cardiology |
| Symptoms | Palpitations, chest tightness, neck pulsation |
| Diagnostic method | electrocardiogram, electrophysiological study |
| Differential diagnosis | Atrioventricular reentrant tachycardia, focal atrial tachycardia, junctional ectopic tachycardia |
| Treatment | vagal manoeuvres, adenosine, ablation |
| Medication | adenosine, calcium channel antagonists, beta blockers, flecainide |
AV-nodal reentrant tachycardia (AVNRT) is a type of abnormal fast heart rhythm. It is a type of supraventricular tachycardia (SVT), meaning that it originates from a location within the heart above the bundle of His. AV nodal reentrant tachycardia is the most common regular supraventricular tachycardia. It is more common in women than men (approximately 75% of cases occur in females). The main symptom is palpitations. Treatment may be with specific physical maneuvers, medications, or, rarely, synchronized cardioversion. Frequent attacks may require radiofrequency ablation, in which the abnormally conducting tissue in the heart is destroyed.
AVNRT occurs when a reentrant circuit forms within or just next to the atrioventricular node. The circuit usually involves two anatomical pathways: the fast pathway and the slow pathway, which are both in the right atrium. The slow pathway (which is usually targeted for ablation) is located inferior and slightly posterior to the AV node, often following the anterior margin of the coronary sinus. The fast pathway is usually located just superior and posterior to the AV node. These pathways are formed from tissue that behaves very much like the AV node, and some authors regard them as part of the AV node.
The fast and slow pathways should not be confused with the accessory pathways that give rise to Wolff-Parkinson-White syndrome (WPW syndrome) or atrioventricular reciprocating tachycardia (AVRT). In AVNRT, the fast and slow pathways are located within the right atrium close to or within the AV node and exhibit electrophysiologic properties similar to AV nodal tissue. Accessory pathways that give rise to WPW syndrome and AVRT are located in the atrioventricular valvular rings. They provide a direct connection between the atria and ventricles, and have electrophysiologic properties similar to muscular heart tissue of the heart's ventricles.