Atrial decremental evoked potentials accurately determine the critical isthmus of intra-atrial re-entrant tachycardia

We have shown before, the utility of DEEP mapping in identifying critical isthmus of scar VT. We hypothesized that, as intra-atrial re-entrant tachycardia (IART) substrate is similar to scar VT by virtue of surgical scars, DEEP mapping could be useful in identifying critical targets for ablation. Two patients with corrected transposition of great arteries (cc TGA) and previous cardiac surgery were selected for the study. Both had recurrent symptomatic IART prompting multiple hospital visits. A decapolar coronary sinus catheter was used for both patients. For the first patient a 64-electrode basket array and for the second patient a duo-decapolar catheter was used for mapping. The late potentials and decremental local potentials were annotated on the electro-anatomical map (CARTO, Biosense Webster, Israel). In sinus rhythm, a pacing train was applied from the CS proximal electrode, and extra stimulus was introduced. The site with maximum local electrogram decrement was considered the critical isthmus and was ablated. The arrhythmia was non-inducible after ablation at this DEEP site for both patients. DEEP mapping was useful in localizing the critical ablation target in IART. The full-length version of this report can be viewed at: https://www.escardio.org/Education/E-Learning/Clinical-cases/Electrophysiology.