AV Nodal Reentrant Tachycardia

For AV nodal reentrant tachycardia (AVNRT) to occur, two conduction pathways through the AV node are required (dual AV nodal physiology): an alpha pathway with slow conduction and a short refractory period, and a beta pathway with fast conduction and a long refractory period. In its typical form, anterograde activation occurs over the slow pathway and retrograde activation over the fast pathway, followed by anterograde ventricular activation through the His-Purkinje system. Atrial activation may occur before, during, or at the end of the QRS complex.

Electrocardiographic Criteria

• The retrograde P wave may be hidden within the QRS complex or appear after the QRS, forming a pseudo-s wave in II, III, and aVF and a pseudo-r’ in V1
• Short RP interval, < 70 ms
• Regular RR interval
• HR usually between 150 and 250 bpm

ECG in AV Nodal Reentrant Tachycardia

AV nodal reentrant tachycardia. Episode of narrow QRS tachycardia with pseudo-s waves in the inferior leads (II, III, and aVF) and pseudo-r’ in V1, produced by retrograde atrial activation, which disappear after conversion to sinus rhythm (next ECG).

Sinus rhythm. Compare the baseline ECG in sinus rhythm with the ECG during AVNRT.

Related Topics

• Atrioventricular Reentrant Tachycardia (AVRT)