Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University, Beijing, China.
Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University, Beijing, China.
Heart Rhythm. 2020 Nov;17(11):1856-1863. doi: 10.1016/j.hrthm.2020.06.014. Epub 2020 Jun 18.
The moderator band (MB) is an endocavitary structure with only 2 exits to the bulk of the ventricular myocardium. Whether this may lead to specific electrophysiological characteristics remains unknown.
The purpose of this study was to investigate electrocardiographic (ECG), activation, and pace mapping characteristics of MB-originated ventricular arrhythmias (VAs).
Mapping and ablation of MB-VAs were performed in 12 patients under the guidance of a 3-dimensional electroanatomic mapping system and intracardiac echocardiography and ECG, and mapping data were analyzed. Of these patients, 11 underwent pace mapping study of 6 sites around the MB and the QRS morphology was compared.
The earliest activation site was free wall (FW) insertion in 8 patients (66.7%) and MB body in 4 patients (33.3%), preceding the QRS onset by 17.8±4.7 ms, and Purkinje-like potential was observed in 6 (50.0%). VAs were eliminated at the earliest activation site in the procedure, but recurrence was documented in 2 cases (16.7%) during a follow-up of 13.4±7.8 months. Pacing QRS complex from the MB was characterized by short QRS duration (P<.001), short intrinsicoid deflection time (P<.001), later precordial transition (P=.025), and notch on the descending limb of the inferior leads (P<.001) as compared with pacing from the adjacent anterior-lateral FW, and that notch could also differentiate MB from the anterior papillary muscle (P=.027). However, pacing QRS is identical between the MB body and the FW insertion in 11 of 11 patients and between the septal insertion and the MB body in 7 of 11 patients.
Bidirectional conduction via the 2 exits during MB-VAs contributed to distinct ECG and electrophysiological characteristics, while pace mapping is of limited value in defining the ablation target.
调节带（MB）是一种腔内心内结构，仅有 2 个出口通向大部分心室心肌。这是否会导致特定的电生理特征尚不清楚。
本研究旨在探讨 MB 起源室性心律失常（VA）的心电图（ECG）、激活和起搏标测特征。
在三维电生理标测系统和心腔内超声的引导下，对 12 例 MB-VA 患者进行标测和消融，分析标测数据。其中 11 例患者进行了 MB 周围 6 个部位的起搏标测研究，并比较了 QRS 形态。
最早的激活部位是 8 例患者（66.7%）的游离壁（FW）插入部位和 4 例患者（33.3%）的 MB 体部，比 QRS 起始提前 17.8±4.7ms，6 例（50.0%）观察到浦肯野样电位。在该过程中，最早的激活部位消除了 VA，但在 13.4±7.8 个月的随访中，有 2 例（16.7%）记录到复发。MB 起搏的 QRS 波群特点为 QRS 时限短（P<.001）、固有内反射时间短（P<.001）、胸前导联过渡晚（P=.025）、下壁导联降支有切迹（P<.001），与邻近前外侧 FW 起搏相比，该切迹也可将 MB 与前乳头肌区分开（P=.027）。然而，在 11 例患者中，有 11 例 MB 体部和 FW 插入部起搏 QRS 完全相同，在 11 例患者中有 7 例 MB 间隔插入部和 MB 体部起搏 QRS 完全相同。
MB-VA 期间通过 2 个出口的双向传导导致了独特的 ECG 和电生理特征，而起搏标测在确定消融靶点方面的价值有限。
