To Explore The Maintenance Mechanism Of Reentrant Atrial Tachycardia Using Ultra-high Density Mapping Technology

Objectives: Reentrant atrial tachycardia(RAT)is a common clinical arrhythmia,However,how can it be sustained has not been fully elucidated.This study aimed to use ultra-high density mapping technology to study the electrophysiological characteristics of all types of reentrant atrial tachycardia and clarify its sustaining mechanism.This might provide a theoretical basis for developing individualized substrate-based ablation strategies.Methods: In the past three years,all the RAT patients who used the ultra-high-density mapping system(Rhythmia)were included in the study.The clinical data,intraprocedural electrophysiological characteristics and the offline analysis data were collected.We classified all the RATs into five categories based on the maintaining mechanisms: A: very large loop without slow conduction;B: large loop with one typical slow conduction area;C: large loop with multiple slow conduction areas;D: normal loop without slow conduction area,but with the shortened refractory period;E: small ring with significantly slow conduction.Results: A total of 62 patients with 96 types of RAT were enrolled.The ablation strategy was developed based on the results of the ultra-high-density mapping.The immediate success rate of the procedure was 100%.Offline analysis showed that there were 21 cases with mean cycle length(CL)of 243.1±32.4 ms and mean circuit length of 174.8±36.6 mm in group A;40 cases with mean CL of 263.7±48.4 ms and mean circuit length of 145.4±33.7 mm in group B;28 cases with mean CL of 293.3±55.9 ms and mean circuit length of 145.1±36.9 mm in group C;3 cases with median CL of 180 ms and median circuit length of 114.2 mm in group D;and 4 cases with median CL length of 289.5 ms in group E among all 96 RATs.Conclusions: The sustained mechanism of single-loop reentrant atrial tachycardia varies from patient to patient based on the individualized arrhythmogenic substrate.Ultra-high-density mapping can accurately display the reentrant pathway,the critical electrophysiological area and the key anatomical isthmus,provide a reasonable personalized ablation strategy.