CONGRESS ABSTRACT

Introduction Slow pathway ablation is currently the target for AV nodal reentrant tachycardia (AVNRT) with a high success rate of almost 100% and 0.5% to 2% risk of II- to III-degree AV block. Kock triangle (KT) mapping is helpful to define the fast and slow pathway separation, demonstrating the physiologic anteroseptal location of the fast pathway. We aimed to describe the KT mapping by means of electroanatomic (EA) activation mapping of slow and fast pathways dislocation, which was performed beside the conventional EP mapping.   Methods KT was mapped by conventional EP technique: atrial pacing from anteroseptal (AS), midseptal (MS) and posteroseptal (PS) regions, performed with a 4 mm ablating catheter; a quadripolar diagnostic catheter was positioned on the His region. The EA activation mapping was performed by means of Ensite X system (Abbott Medical); the window of interest was set from the pacing atrial spike to the ventricular EGM. The time interval from the spike to the His deflection was measured to define the fast pathway location. On the mapping catheter tracing an annotation was set, timed to the His deflection on His tracing; annotation was set even when no His deflection was recorded on ablator tracing as in MS and PS regions (“mirroring”). The KT was mapped before and after successful elimination of the slow pathway.  Results In 7 consecutive AVNRT patients, EA mapping has been performed. All underwent to a successful procedure targeting the slow pathway elimination (no residual AVNRT or AV node Jump induced, also during isoproterenol infusion). During the pre-ablation mapping a progressive prolonged interval from the spike to His deflection was found in all cases (anteroseptal fast pathway dislocation) which was confirmed by the EA activation mapping. (Fig 1) During the post-ablation mapping a residual dual AV node physiology was still found in all cases. (Fig 2) Conclusion The EA activation mapping of KT may help to define the AV node dual physiology, beside the conventional EP mapping.