Abstract
BackgroundLeft atrial roof-dependent tachycardias (LARTs) are common macroreentrant atrial tachycardias (ATs). We sought to characterize clinical LARTs using an ultra-high resolution mapping system.MethodsThis study included 22 consecutive LARTs in 21 patients who underwent AT mapping/ablation using Rhythmia systems.ResultsThree, 13, 4, and 2 LART patients were cardiac intervention naïve (Group-A), post-roof line ablation (Group-B), post-atrial fibrillation ablation without linear ablation (Group-C), and post-cardiac surgery (Group-D), respectively. The mean AT cycle length was 244 ± 43 ms. Coronary sinus activation was proximal-to-distal or distal-to-proximal in 16 (72.7%) ATs. The activation map revealed 13 (59.1%) clockwise and 9 (40.9%) counter-clockwise LARTs. A 12-lead synchronous isoelectric interval was observed in 10/19 (52.6%) LARTs. The slow conduction area was identified on the LA roof, anterior/septal wall, and posterior wall in 18, 6, and 2 ATs, respectively. Twenty concomitant ATs among 13 procedures were also eliminated, and peri-mitral AT coexisted in 7 of 9 non-group-B patients. In group-B, the conduction gap was predominantly located on the mid-roof. Sustained LARTs were terminated by a single application and linear ablation in 6 (27.3%) and 9 (40.9%), while converting to other ATs in 7 (31.8%) LARTs. Complete linear block was created without any complications in all, however, ablation at the mid-posterior wall was required to achieve block in 4 (18.2%) procedures. During 14.0 (6.5–28.5) months of follow-up, 17 (81.0%) and 19 (90.5%) patients were free from any atrial tachyarrhythmias after single and last procedures.ConclusionsThe LART mechanisms were distinct in individual patients, and elimination of all concomitant ATs was required for the management.
Highlights
Left atrial roof-dependent tachycardias (LARTs) are common macroreentrant atrial tachycardias (ATs)
We found that (1) ultra-high resolution mapping with the Lumipoint algorithm successfully identified the critical isthmus of the ATs and lead to a high success rate, (2) almost all patients had AF, and peri-mitral ATs often coexisted with roof-dependent ATs, (3) slow conduction areas were located on the left atrial (LA) roof and on the anterior/septal and/or posterior wall, (4) the majority
Slow conduction areas were identified on the LA roof and on the anterior/septal and posterior walls. It was significantly more frequently identified at other sites than the LA roof in non-group-B patients than group-B patients. All these data suggested that (1) a roof line ablation increased the risk of a roof-dependent AT due to a conduction gap and (2) slow conduction due to atrial disease on the LA anterior/septal and posterior wall contributed to the maintenance of roof-dependent ATs even without a history of linear ablation
Summary
Left atrial roof-dependent tachycardias (LARTs) are common macroreentrant atrial tachycardias (ATs). We sought to characterize clinical LARTs using an ultra-high resolution mapping system. The macroreentrant ATs, including left atrial (LA) roofdependent tachycardias, are the most common ATs and creating durable linear conduction block to interrupt the reentrant circuit is required. Ultra-high resolution maps can be created with Rhythmia mapping system (Boston Scientific, Natick, MA, USA) and a 64-electrode minibasket mapping catheter (Orion, Boston Scientific) to clarify the mechanisms of tachycardia circuit [4,5,6,7,8,9,10,11,12,13,14]. We aimed to characterize LA roof-dependent ATs using this system
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