Mapping of Focal Atrial Tachycardia With an Uninterpretable Activation Map After Extensive Atrial Ablation

Abstract

All procedures were performed under conscious sedation and local anesthetized state. A 6F quadripolar and a decapolar catheter were © 2014 American Heart Association, Inc. Original Article Circ Arrhythm ElectrophysiolBackground-Atrial tachycardias (ATs) after extensive ablation are increasingly common and challenging arrhythmias. The prolonged intra-atrial conduction time (IACT) during ATs in the milieu may complicate the mapping of focal ATs. In this present study, we aim to characterize the electrophysiological features of ATs in this unique setting and to delineate an effective mapping strategy further. Methods and Results-In total, 13 patients (average age, 59±7 years) in a cohort of 80 patients referred for AT ablation were selected for the study. The patients all demonstrated an undistinguishable map not ready to be interpreted the 3-dimensional mapping. A total of 13 ATs were mapped with mean tachycardia cycle length of 296±70 ms. Two activation patterns were identified, which were referred to as pseudo-macroreentry and chaotic activation. The former was a focal AT originating from the vicinity of an area of conduction block with the IACT less than the window of interest duration (4 cases; IACT/ window of interest ratio range, 0.93-0.98). The latter refers to a focal AT exhibiting a disorderly color mapping display with IACT exceeding the window of interest duration (9 cases; IACT/window of interest ratio range, 1.02-1.29). The IACT was determined after resetting the annotation. All ATs were successfully eliminated at the originating site. Conclusions-We delineated a series of focal ATs in the setting of a significantly prolonged IACT encountered in patients after previous extensive ablation. Two activation patterns were identified, which may help facilitate the mapping of focal ATs in this setting.

Regional isolation in the right atrium with disruption of intra‐atrial conduction after catheter ablation of atrial tachycardia

“…Unintentional isolation of atrial structures has been described in a limited number of case reports. More commonly, significant prolongation of inter‐atrial conduction times has been recognized after extensive atrial ablations . Inadvertent isolation of the left atrial appendage has been documented during complex ablation of persistent atrial fibrillation and left ATs .…”

Unifying Algorithm for Mechanistic Diagnosis of Atrial Tachycardia

“…Therefore, activation patterns in focal AT can seem to be macroreentrant (pseudo-macroreentry) when sites of origin occur contiguous to areas of preexisting conduction block. 22,23 Finally, we also recognize that the descriptors micro-and by guest on May 11, 2018 http://circep.ahajournals.org/ Downloaded from…”

A Prospective Study of Ripple Mapping in Atrial Tachycardias

“…2 However, low voltage and fractionated electrograms, commonly found in these atria, are prone to incorrect assignment of local activation time and WOI errors. [3][4][5] Alternatively, the tachycardia mechanism can be located using entrainment, but this risks transforming or terminating the clinical tachycardia and local capture within scarred areas can be difficult. 6 A combined strategy using both activation mapping and entrainment is often used to overcome these individual limitations.…”