Wang Hao, Chen Jindong, Zhuang Xiaohua, Xi Siqi, Gan Tian, He Ben, Zhao Liang
Department of Cardiology, Shanghai Chest Hospital, School of Medicine, Shanghai Jiao Tong University, 200003 Shanghai, China.
Department of Cardiology, Shanghai Pudong Hospital, Fudan University Pudong Medical Center, 201399 Shanghai, China.
Rev Cardiovasc Med. 2023 Nov 24;24(11):329. doi: 10.31083/j.rcm2411329. eCollection 2023 Nov.
The misinterpretation of activation propagation within low voltage zone (LVZ) can complicate atrial tachycardia (AT) mechanism analysis, especially in patients with remodeled atrial substrate. This study investigated the impact of low voltage threshold adjustment (LVTA) on left atrial (LA) tachycardia activation mapping interpretation.
We identified 55 ATs in 42 patients undergoing catheter ablation for LA tachycardia, with a mean LA voltage of 0.5 mV. Activation mapping of LA or both atria was used to evaluate AT mechanisms before and after LVTA. Patients underwent regular clinic follow-up after the procedure.
Comparing activation mapping before and after LVTA revealed four categories: (1) complete change in AT circuit and ablation design in 9 ATs; (2) an unchanged AT circuit but tailored ablation design in 16 ATs; (3) identification of bystander gaps in 3 ATs; (4) an unchanged AT circuit and ablation design in 27 ATs. Effective ablation, defined as AT termination or circuit change, was obtained in all 9 Type 1 ATs and 15 of 16 Type 2 ATs by targeting the critical area identified by activation mapping after LVTA. After a median follow-up of 16.5 months, the cumulative freedom from AT was 69.3%.
In patients with low LA voltage, conduction propagation hidden within LVZ was not uncommon, but is often excluded from activation mapping. LVTA can uncover this subtle conduction propagation with reliable accuracy, improving the veracity of activation mapping, and helping guide subsequent ablation.
低电压区（LVZ）内激动传导的误判会使房性心动过速（AT）机制分析变得复杂，尤其是在心房基质重塑的患者中。本研究调查了低电压阈值调整（LVTA）对左房（LA）心动过速激动标测解读的影响。
我们在42例因LA心动过速接受导管消融的患者中识别出55例AT，平均LA电压为0.5 mV。在LVTA前后，使用LA或双房的激动标测来评估AT机制。术后患者接受定期门诊随访。
比较LVTA前后的激动标测发现有四类情况：（1）9例AT的AT环路和消融设计完全改变；（2）16例AT的AT环路不变但消融设计调整；（3）3例AT中发现旁观者间隙；（4）27例AT的AT环路和消融设计不变。通过针对LVTA后激动标测确定的关键区域，所有9例1型AT和16例2型AT中的15例均实现了有效消融，定义为AT终止或环路改变。中位随访16.5个月后，AT无复发的累积自由度为69.3%。
在LA电压低的患者中，隐藏在LVZ内传导并不少见，但在激动标测中常被排除。LVTA能够以可靠的准确性揭示这种细微的传导，提高激动标测的准确性，并有助于指导后续消融。
