Abstract Aims Three-dimensional mapping systems have been utilized to reduce fluoroscopy and minimize complications in patients with AVNRT. Recently, voltage-gradient mapping has been introduced to visualize low-voltage bridges. However, there are some limitations of voltage assessment due to catheter contract. Therefore, new Slow pathway Late Activation Mapping (SLAM) has been recently used to reveal slow conduction zone in AVNRT patients. Method and materials Seven adult patients with diagnosis of typical AVNRT were included. Electro anatomical mapping systems was used in all patients. Voltage and late activation mapping were performed with high-definition multipolar catheter. His cloud was also tagged in all patients. Voltage of 0.20-0.50 mV was used to delineate voltage-bridges. Latest activation in the SP area along with voltage-guided bridges were targeted with either radiofrequency ablation (RFA) or focal cryoablation (Figure 1 and 2). Results Limited fluoroscopy was used in 4 patients. Acute success was achieved in all patients. Patients had no structural heart disease. Detailed clinical and procedural data was depicted in Table. Cryoablation was used in 2 patients due to very small Koch triangle. Each cryolesion applied for 240 secs and overall, 3-4 lesions were delivered. Ablation at late activation areas successfully eliminated slow pathway. In most of cases, one ablation lesion was adequate to see junctional beats and elimination of dual AV nodal physiology. Conclusion SLAM is effective in guiding catheter ablation of AVNRT, with a complete acute success rate and no recurrences at short-term follow-up.

SLAM-guided catheter ablation of AVNRT: single-center experience