Mapping and ablation of clinical spontaneous peri-mitral atrial tachycardias using an ultra-high resolution mapping system.

Abstract Background Peri-mitral atrial tachycardias (PMATs) are common ATs, yet the mechanisms vary. Objective We sought to characterize clinical spontaneous PMATs using an ultra-high resolution mapping (UHRM) system. Methods This study included 32 consecutive PMATs in 31 patients who underwent AT mapping/ablation using UHRM systems. Results Six, 10, 11, and 5 PMATs occurred in cardiac intervention-naive (Group-A), post- lateral/posterior mitral isthmus linear ablation (Group-B), post-atrial fibrillation ablation without mitral isthmus linear ablation (Group-C), and post-cardiac surgery (Group-D) patients, respectively. Group-A tended to be older and more likely female and had sinus node or atrioventricular conduction disturbances more frequently. A 12-lead synchronous isoelectric interval was observed in 15 (46.9%) PMATs. Coronary sinus activation was proximal-to-distal or distal-to-proximal except in 3 PMATs with straight patterns owing to epicardial gaps. LA anterior/septal wall (LAASW) low voltage areas were smallest in group-B. Slow conduction areas (SCAs) were identified in 26 (81.2%) PMATs and were on the LAASW in all group-A and group-D patients. The conduction velocity in the SCAs was slowest in group-B. In group-B, all PMATs were terminated by single applications, and the gaps were located epicardially in 5/10 (50%). Anterior (n=23) or lateral/posterior (n=9) mitral isthmus linear block was successfully created without any complications in all. Twenty-five concomitant ATs among 18 (58.1%) patients were also eliminated. During 20.0[11.0-40.0] months of follow-up, 28 (90.3%) patients were free from any atrial tachyarrhythmias. Conclusion A UHRM-guided approach with identification of the individual tachycardia mechanism should be the preferred strategy since arrhythmia mechanisms are distinct and complex.