Hsia Henry H, Lin David, Sauer William H, Callans David J, Marchlinski Francis E
Cardiovascular Medicine Division, Stanford University, Stanford, California 94305-5233, USA.
Heart Rhythm. 2006 May;3(5):503-12. doi: 10.1016/j.hrthm.2006.01.015. Epub 2006 Feb 28.
Detailed anatomic characterization of endocardial substrate of ventricular tachycardia (VT) is limited.
The purpose of this study was to determine the endocardial dimensions and local electrogram voltage characteristics of the reentrant circuit. VT-related conducting channels corresponding to zones of slow conduction may be identified.
Electroanatomic mapping was performed in 26 patients with uniform VT. Entrainment mapping was performed in 53 VTs, of which 19 entrance, 37 isthmus, 48 exit, and 32 outer loop sites were identified. The color display of voltage maps was adjusted to identify conducting channels associated with VT circuits. A conducting channel was defined as a path of multiple orthodromically activated sites within the VT circuit that demonstrated an electrogram amplitude higher than that of surrounding areas as evidenced by voltage color differences.
Forty-seven (84%) of 56 entrance or isthmus sites were located within dense scar (<0.5 mV). Nearly all exits (92%) were located in abnormal endocardium (<1.5 mV), with more than half (54%) located in the border zone (0.5-1.5 mV). VT-related conducting channels was identified in 18 of 32 VTs with detailed mapping (average length 32 +/- 22 mm). The voltage threshold in the conducting channels ranges from 0.1 to 0.7 mV (mean 0.33 +/- 0.15 mV).
(1) Most entrance and isthmus sites of hemodynamically stable VT are located in dense scar, whereas exits are located in the border zone. (2) VT-related conducting channels may be identified by careful voltage threshold adjustment. These findings have important implications regarding strategies for substrate-based VT ablation.
室性心动过速（VT）心内膜基质的详细解剖特征尚不明确。
本研究旨在确定折返环路的心内膜尺寸和局部心电图电压特征。识别与缓慢传导区域相对应的VT相关传导通道。
对26例持续性VT患者进行电解剖标测。对53次VT进行拖带标测，其中确定了19个入口、37个峡部、48个出口和32个外环部位。调整电压图的颜色显示以识别与VT环路相关的传导通道。传导通道定义为VT环路内多个顺向激活部位的路径，其心电图振幅高于周围区域，电压颜色差异可证明这一点。
56个入口或峡部部位中的47个（84%）位于致密瘢痕内（<0.5 mV）。几乎所有出口（92%）位于异常心内膜（<1.5 mV），其中一半以上（54%）位于边界区（0.5 - 1.5 mV）。在32次进行详细标测的VT中，有18次识别出了VT相关传导通道（平均长度32 +/- 22 mm）。传导通道中的电压阈值范围为0.1至0.7 mV（平均0.33 +/- 0.15 mV）。
（1）血流动力学稳定的VT的大多数入口和峡部部位位于致密瘢痕内，而出口位于边界区。（2）通过仔细调整电压阈值可识别VT相关传导通道。这些发现对基于基质的VT消融策略具有重要意义。
