探测深度对心脏光学标测中荧光信号的影响

为了估计心脏光学标测过程中不同探测深度对光标测结果的影响，利用电兴奋跨壁传导模型和荧光传输模型，模拟了心室电兴奋跨壁传播时跨膜电位的分布和不同光探测深度的荧光信号，并将深度权重的荧光信号与组织表层细胞的荧光信号做了比较，并分析了产生差异的原因．研究表明：如果大多数荧光来自组织的近表层（小于0．5mm），光探测深度的影响几乎可以忽略；当探测深度增加时（大于等于0．5mm），尤其在螺旋波条件下，两种动作电位在上升时间、幅度和时程上的差异随探测深度的增加而加大，所以需要对以往由心肌表面电标测得到的电生理指标做相应修正．

Effect of Probing Depth on Fluorescence Signal During Cardiac Optical Mapping

To investigate the effect of different probing depths during cardiac optical mapping,the electrical transmural propagation model,and the fluorescence transport model were adopted to simulate the distribution of transmembrane potentials during the transmural propagation and the fluorescence signals coming form three different optical probing depths.The depth-weighted optical action potential is compared with the action potential of the top layer,and the discrepancy is analyzed.The results indicate that the effect of optical probing depth may be ignored as most of the fluorescence only comes from the subsurface(less than 0.5 mm) but the discrepancy of the action upstroke duration,the signal amplitude and duration between two action potentials are enhanced with the increase of the probing depth (greater than or equal to 0.5 mm),especially in the spiral wave activity.So it is necessary to correspondingly correct the judgments of the physiological states of myocardial cells generally obtained by electrodes from the tissue surface.