Line stimulation parallel to myofibers enhances regional uniformity of transmembrane voltage changes in rabbit hearts.
Line stimulation parallel to myofibers enhances regional uniformity of transmembrane voltage changes in rabbit hearts.
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平行于肌纤维的线刺激增强了兔心脏跨膜电压变化的区域均匀性。
DOI：
10.1161/01.res.81.2.229
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发表时间：
1997
影响因子：
20.1
通讯作者：
Baynham,TC
中科院分区：
文献类型：
--
作者：
Knisley,SB;Baynham,TC
在单极点刺激期间心脏中的跨膜电压（Vm）变化（ΔVm）的符号是不均匀的，这引入了依赖于纤维取向的Vm依赖性离子通道的状态分散。我们假设平行于心脏纤维的线刺激增加了ΔVmsign的区域均匀性。为了验证这一点，我们在离体兔心脏中评估了单极线刺激产生的电极电流分布和Δ Vm。Vm敏感荧光染料di-4-ANEPPS和激光扫描仪在8×8 mm心外膜区域的63个点处提供Δ Vm测量值。在相对于纤维方向的特定角度下测试线刺激。电流峰值出现在电极末端。对于平行于纤维（0°）的电极，两端以外区域的心外膜表现出不均匀的ΔVmsign，而两端之间的心外膜表现出均匀的ΔVmsign，在阳极脉冲期间基本为负（超极化），在阴极脉冲期间为正（去极化）。当刺激角度相对于纤维长轴增加时，两端之间的Δ Vm符号变得不那么均匀。在90°时，端部之间的ΔVmsign是不均匀的，并且通常是相反的，靠近电极与远离电极。线刺激过程中Δ Vm的空间分布可以从点刺激的各向异性效应中定性预测，前提是考虑电极上沿着的点和末端附近具有较高电流的点的组合效应。对于双相线刺激，第二相期间的Δ Vm与单独给予的相效应的时间总和弱相关，表明总和预测ΔVm的能力有限。因此，刺激期间ΔVmsign的均匀性在平行于纤维的线电极的端部之间的区域中增强。这可以减少该区域中的Vm依赖性离子通道状态的致热分散。
The sign of transmembrane voltage (Vm) change (ΔVm) in the heart during unipolar point stimulation is nonuniform, which introduces dispersion of states of Vm-dependent ion channels that depends on fiber orientation. We hypothesized that line stimulation parallel to cardiac fibers increases regional uniformity of the ΔVmsign. To test this, we evaluated electrode current distribution and ΔVmproduced by unipolar line stimulation in isolated rabbit hearts. The Vm-sensitive fluorescent dye, di-4-ANEPPS, and a laser scanner provided ΔVmmeasurements at 63 spots in an 8×8-mm epicardial region. Line stimulation was tested at specific angles with respect to the fiber direction. Current peaks occurred at electrode ends. For electrodes parallel to fibers (0°), epicardium in regions beyond the ends exhibited a nonuniform ΔVmsign, whereas epicardium between the ends exhibited a uniform ΔVmsign that was essentially negative (hyperpolarized) during anodal pulses and positive (depolarized) during cathodal pulses. The ΔVmsign between the ends became less uniform when the stimulation angle was increased relative to the long axis of the fibers. At 90°, the ΔVmsign between the ends was nonuniform and was frequently opposite, near versus away from the electrode. Spatial distributions of ΔVmduring line stimulation were qualitatively predictable from anisotropic effects of point stimulation provided that combined effects of points along the electrode and points with higher current near ends were considered. For biphasic line stimulation, ΔVmduring the second phase was weakly correlated with the temporal sum of effects of phases given individually, indicating limited ability of summation to predict ΔVm. Thus, uniformity of the ΔVmsign during stimulation is enhanced in the region between the ends of a line electrode parallel to fibers. This may lessen arrhythmogenic dispersion of Vm-dependent ion channel states in the region.
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心室细胞电场刺激期间跨膜电位变化的光学测量。
影响因子：
20.1
作者：
Knisley,SB;Blitchington,TF;Hill,BC;Grant,AO;Smith,WM;Pilkington,TC;Ideker,RE
通讯作者：
Ideker,RE
通过对称双相除颤器波形改善心肌细胞兴奋。
DOI：
10.1152/ajpheart.1987.253.6.h1418
发表时间：
1987
期刊：
The American journal of physiology
影响因子：
--
作者：
Jones,JL;Jones,RE;Balasky,G
通讯作者：
Balasky,G
刺激内极性反转对青蛙和兔心肌电场刺激阈值的影响
DOI：
--
发表时间：
1992
期刊：
影响因子：
--
作者：
S. Knisley;William M. Smith;R. Ideker
通讯作者：
R. Ideker
DOI：
10.1098/rspb.1946.0024
发表时间：
1946-01-01
期刊：
PROCEEDINGS OF THE ROYAL SOCIETY SERIES B-BIOLOGICAL SCIENCES
影响因子：
--
作者：
HODGKIN, AL;RUSHTON, WAH
通讯作者：
RUSHTON, WAH
影响因子：
2.7
作者：
J. M. Saypol;B. Roth
通讯作者：
B. Roth