The aim of the present work is to analyze the capacity of high resolution mapping systems to determine the precise location of the AV node and peri-nodal slow-conducting pathways, using standard recording parameters, but also off-line additional filter changes and additional techniques (conduction velocities, isochrones and dV/dt). The investigative team plan a prospective monocentric study.

Detailed high resolution mapping of the Koch triangle and neighboring areas will be collected through the RHYTHMIA HDx 3D electro-anatomical mapping system and the multipolar ORION catheter. This sample will consist of 2 groups of patients: the first will include patients referred for AVNRT ablation and the second will include control patients (without AVNRT), referred for another indication requiring similar mapping system. If visualized, position of the slow pathway and AV node will be compared with the ablation areas, which will be set conventionally under fluoroscopy.

Inclusion Criteria:

Group 1: Patients without heart disease presenting with reciprocal tachycardia by intra-nodal reentry.

Group 2: Control subjects, without nodal tachycardia, without heart disease, and admitted for ablation of atrial fibrillation or ventricular extrasystoles on a healthy heart and with a 3D system.

Exclusion Criteria:

• Presence of underlying structural heart disease or history of atrial ablation or atrial tachycardia
• Minor or protected patient
• Patient under guardianship, curatorship or safeguard of justice