Ultrahigh‐density mapping supplemented with global chamber activation identifies noncavotricuspid‐dependent intra‐atrial re‐entry conduction isthmuses in adult congenital heart disease

Abstract

Objective To evaluate the role of ultrahigh‐density mapping for conduction isthmus (CI) characterization in adult congenital heart disease (ACHD). Background Catheter ablation remains suboptimal for ACHD with atypical intra‐atrial reentrant tachycardias (IART) that can be challenging to define using existing mapping technology. Methods An ultrahigh‐density mapping system was selectively employed over a 1‐year period for procedures involving noncavotricuspid isthmus‐dependent‐IART. A global activation histogram (GAH) was assessed for the ability to predict ablation targets. Procedural characteristics were compared to a group of matched controls. Results Twenty patients (mean age 43 ± 15, 70% male) underwent 20 procedures targeting 34 tachycardias during the study period. Diagnoses included single ventricle (8), tetralogy of Fallot (2), left heart obstruction (3), Ebstein's anomaly (2) atrial septal defect (2), Mustard operation (2), and Rasteilli operation (1). Prior catheter ablation/Maze operation had been performed in 12 (60%). The median time per map was 21 minutes (interquartile range [IQR], 16‐32), representing 14 834 points per map (IQR 9499‐43 191; P < .001 vs controls). Review of GAH maps showed lower trough values were associated with more favorable IART CI characteristics (P ≤ =.001 for all). Acute success was achieved in 19/20 (95%) procedures, with tachycardia termination during the first lesion in eight cases (P = .02 vs controls). There was one recurrence during 0.6 years follow‐up. Conclusions Ultrahigh‐density mapping supplemented with the GAH tool was effective for CI identification in a cohort of complex ACHD patients. Catheter ablation was more efficient compared to controls, suggesting precise CI characterization using this technology.

Characterization of temporal electrical activity patterns for detection of critical isthmus regions of recurrent atypical atrial flutter

“…In our study, 1.7 ATs per patient were detected and mapped. This is in line with previous studies, in which 1.3–1.6 AT forms per patient were reported 9,15,21,22 . The mean CL of our macro re‐entrant AT was 291 ms, which is also comparable to previous studies (CL range from 275 to 299 ms) 15,21 …”

“…Consistent with the results of previous studies, a history of preablation or cardiac surgery was present in most of the studied patients 5,18–20 . Mean age in our study cohort was 71 years, which is rather old compared to patient cohorts of previous studies 9,15,21 . In our study, 1.7 ATs per patient were detected and mapped.…”

“…In our study, 60.9% of all isthmi of all analyzed minima were located within the AAF re‐entry circuit. These results go along with data from previously published reports, in which 60%–67% of the isthmi were located in the AT re‐entry 9,21 …”

Targeted cluster ablation of non‐CTI‐dependent atrial arrhythmias in congenital heart disease using ultrahigh‐definition mapping

“…Our median ablation time necessary for the acute procedural success of 3.1 min for the non‐CTI group was relatively low, in spite of multiple tachycardias ablated in 14 of 42 procedures. Previous studies in CHD using the Rhythmia System reported a mean procedure ablation time ranging from 14 to 39 min 6,8,10,11,18,21,22 . Despite our short ablation time, there was a low rate of recurrence for the ablated arrhythmias, in particular for the non‐CTI group.…”

“…Previous studies in CHD using the Rhythmia System reported a mean procedure ablation time ranging from 14 to 39 min. 6,8,10,11,18,21,22 Despite our short ablation time, there was a low rate of recurrence for the ablated arrhythmias, in particular for the non-CTI group. At our repeat procedures, the previously ablated sites or areas of conduction block had remained persistently blocked and the sustainability of our results could be confirmed with other HD mapping systems (Figure S1).…”