STIMULUS-INDUCED CRITICAL-POINT - MECHANISM FOR ELECTRICAL INITIATION OF REENTRY IN NORMAL CANINE MYOCARDIUM
STIMULUS-INDUCED CRITICAL-POINT - MECHANISM FOR ELECTRICAL INITIATION OF REENTRY IN NORMAL CANINE MYOCARDIUM
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DOI：
10.1172/jci113945
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发表时间：
1989-03-01
影响因子：
15.9
通讯作者：
IDEKER, RE
中科院分区：
文献类型：
--
作者：
FRAZIER, DW;WOLF, PD;IDEKER, RE
假设进行了测试，过早（S2）的刺激，与相对难治性组织相互作用的领域，可以创建单向的块和折返的不均匀分散的情况下恢复。在14只狗的正常右心室（RV）心肌的一个小区域的同时记录从117至120个透壁或心外膜电极。从标测区域一侧的一排电极进行S1起搏产生平行的激动等时线，随后是均匀的平行等恢复线。从网状电极沿标测区域的沿着输送持续3 ms的25至250 V的阴极S2电击，以扫描恢复期，产生垂直于等恢复线的等梯度电场线。在S2模拟后创建环形折返;初始传导远离S2部位，并向更难治组织扩散。右S1（靠近间隔）与顶部S2（靠近肺动脉瓣）和左S1与底部S2的折返是顺时针的;右S1与底部S2和左S1与顶部S2的折返是逆时针的。所有S2电压和耦合间隔的折返回路中心出现在5.1 ± 1.5的电位梯度处。0.6 V/cm（平均值±.标准偏差）和在震前间隔1 ± 1。比2 mA刺激局部确定的不应期长3 ms。因此，当S2场强和组织不应性以彼此成一角度均匀分散时，在S2场强为apx的“临界点”周围发生环形折返。5 V/cm与组织相交大约在其不应期结束时。
The hypothesis was tested that the field of a premature (S2) stimulus, interacting with relatively refractory tissue, can create unidirectional block and reentry in the absence of nonuniform dispersion of recovery. Simultaneous recordings from a small region of normal right ventricular (RV) myocardium were made from 117 to 120 transmural or epicardial electrodes in 14 dogs. S1 pacing from a row of electrodes on one side of the mapped area generated parallel activation isochrones followed by uniform parallel isorecovery lines. Cathodal S2 shocks of 25 to 250 V lasting 3 ms were delivered from a mesh electrode along one side of the mapped area to scan the recovery period, creating isogradient electric field lines perpendicular to the isorecovery lines. Circus reentry was created following S2 simulation; initial conduction was distant from the S2 site and spread towards more refractory tissue. Reentry was clockwise for right S1 (near the septum) with top S2 (near the pulmonary valve) and for left S1 with bottom S2; and counterclockwise for right S1 with bottom S2 and left S1 with top S2. The center of the reentrant circuit for all S2 voltages and coupling intervals occurred at potential gradients of 5.1 .+-. 0.6 V/cm (mean .+-. standard deviation) and at preshock intervals 1 .+-. 3 ms longer than refractory periods determined locally for a 2 mA stimulus. Thus, when S2 field strengths and tissue refractoriness are uniformally dispersed at an angle to each other, circus reentry occurs around a "critical point" where an S2 field of .apprx. 5 V/cm intersects tissue approximately at the end of its refractory period.