Ultrahigh Density Mapping for Multiple Scar-Related Right Atrial Tachycardias in Patients Without Previous Cardiac Surgery

Objective: We sought to investigate the precise electrophysiological mechanisms of multiple scar-related RA ATs using an ultrahigh density mapping system. Methods: Eighteen patients with scar related RA AT and no prior cardiac surgery were enrolled. In each case, we sought to map each AT circuit in detail. Low-voltage zones(LVZs) ,electrically silent areas(ESAs) and lines of double potentials (LDPs) were all visualized on the voltage and activation map. Results: A total of 52 different ATs (mean 3.2{plus minus}1.5 ATs per patient) were observed . We endeavored to complete activation maps for 45 ATs. In all cases, a large area of LVZ was located between the crista terminalis(CT) and the tricuspid annulus(TA). Inside the LVZ, several discrete ESAs or LDPs separated by a low-voltage channel were present. By analyzing activation maps, we classified ATs into six categories. The discrepant location and extension of ESAs were associated with different AT mechanisms. Conclusions: Multiple scar related RA ATs were observed in patients without previous cardiac surgery. The detailed activation patterns of these ATs could be clearly demonstrated by using an ultra-high density mapping system.