High-density Activation Mapping of the Slow Pathwayto Guide Catheter Ablation in Patients With Typical Atrioventricular Nodal Reentrant Tachycardia

Atrioventricular nodal reentrant tachycardia (AVNRT) is the most common supraventricular tachycardia inducible during an electrophysiological study. Although ablative therapy proved to be the treatment of choice, little is known about the components of the tachycardia circuit. The aim of this study is to detect the presence and patterns of specific electrograms representing slow pathway (SP) potentials and to explore Koch's triangle pattern activation during sinus rhythm and/or atrial extraestimulus with a high-density mapping catheter in an attempt to clarify a fast and safety catheter ablation strategy. We hypothesized that, in patients with dual atrioventricular nodal physiology, during sinus rhythm (SR), high-density mapping (HDM) catheters could identify the SP signals, making possible to delineate small areas of slow conduction associated to abnormal electrograms on Koch's triangle. On a second step, radiofrequency (RF) applications safety guided by the HDM obtained with this method, should interrupt the circuit far from the His region. Finally, SP signals should disappear after the RF procedure when performing a new 3D HDM. A control group of patients without AVN dual physiology should show absence of fragmented/slow conduction zones.