Department of Cardiovascular Medicine, Faculty of Medical Sciences, University of Fukui, Fukui, Japan.
J Cardiovasc Electrophysiol. 2021 May;32(5):1305-1319. doi: 10.1111/jce.14983. Epub 2021 Mar 17.
Low voltage areas (LVAs) are most commonly observed on the left atrial (LA) septal/anterior wall.
We explored the mechanisms of LA septal/anterior wall reentrant tachycardias (LASARTs) using ultrahigh resolution mapping.
This study included seven consecutive LASARTs in six patients (75 [62.2-82.8] years, 4 women) who underwent atrial tachycardia (AT) mapping and ablation using Rhythmia systems.
The AT cycle length was 266 (239-321) ms. During ATs, 11.0 (9.0-12.9) cm of LVAs were identified in all, and 0.8 (0.7-1.7) cm of dense scar was identified in four patients. Five ATs rotated around dense scar, while two rotated around functional linear block, which was confirmed during atrial pacing after AT termination. The AT circuit length was 8.7 ± 2.1 cm with a conduction velocity of 30.4 ± 3.7 cm/s. A median of 3.0 (2.0-4.0) slow conduction areas per circuit were identified, and 17/23 (73.9%) areas were present in LVAs, while they were at the border of the LVA and normal voltage areas in the remaining 6/23 (26.1%). Global activation histograms facilitated the identification of the critical isthmus in all. Tailor-made ablation at critical isthmuses successfully eliminated all ATs. However, one patient with AT related to functional linear block experienced recurrent AT related to dense scar, which progressed after the procedure. During a mean 14 ± 13 month follow-up after the last procedure, no patients experienced recurrent ATs without any complications.
LASARTs consist of not only fixed conduction blocks but also functional conduction blocks. Ultrahigh resolution mapping is highly useful to decide the optimal tailor-made ablation strategy based on the mechanisms.
低电压区（LVAs）最常发生在左心房（LA）间隔/前壁。
我们使用超高分辨率标测探索 LA 间隔/前壁折返性心动过速（LASARTs）的机制。
这项研究纳入了 6 名患者的 7 例连续 LASART（75[62.2-82.8]岁，4 名女性），这些患者使用 Rhythmia 系统进行了房性心动过速（AT）标测和消融。
AT 周期长度为 266（239-321）ms。在 AT 期间，所有患者均发现 11.0（9.0-12.9）cm 的 LVAs，4 名患者发现 0.8（0.7-1.7）cm 的致密瘢痕。5 例 AT 围绕致密瘢痕旋转，而 2 例围绕功能性线性阻滞旋转，这在 AT 终止后的心房起搏时得到了证实。AT 环周长为 8.7±2.1cm，传导速度为 30.4±3.7cm/s。每个环中发现 3.0（2.0-4.0）个慢传导区，其中 17/23（73.9%）区位于 LVAs 内，而其余 6/23（26.1%）区位于 LVA 与正常电压区交界处。全局激活直方图有助于识别所有病例的关键峡部。在关键峡部定制消融成功消除了所有 AT。然而，1 例功能性线性阻滞相关的 AT 患者在手术后出现了致密瘢痕相关的复发性 AT。在最后一次手术后平均 14±13 个月的随访中，无患者发生无并发症的复发性 AT。
LASARTs 不仅包括固定的传导阻滞，还包括功能性传导阻滞。超高分辨率标测对于根据机制制定最佳的定制消融策略非常有用。
