Monophasic action potentials generated by bidomain modeling as a tool for detecting cardiac repolarization times
Monophasic action potentials generated by bidomain modeling as a tool for detecting cardiac repolarization times
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DOI：
10.1152/ajpheart.00651.2007
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发表时间：
2007-11-01
影响因子：
4.8
通讯作者：
Taccardi, B.
中科院分区：
文献类型：
--
作者：
Colli-Franzone, P.;Pavarino, L. F.;Taccardi, B.
单极电描记图（EG）和混合（或非正统或单极）单相动作电位（HMAP）是目前唯一提出的细胞外电记录技术，用于在暴露和离体的心脏中获得具有高空间分辨率的心脏恢复图。 HMAP 下冲程复极时间的估计最近一直是争议的主题。本文的目的是通过计算解决有关 HMAP 信息内容的争议，特别是从 HMAP 下冲阶段估计复极时间的可靠性。使用具有短动作电位持续时间区域的各向异性双域模型进行三维数值模拟。计算了靠近或远离永久去极化部位的心外膜刺激引起的 EG、跨膜动作电位 (TAP) 和 HMAP。复极化时间计算为 T 波期间 EG 最快上冲程 (RTeg)、HMAP 最快下冲程 (RTHMAP) 和 TAP 最快下冲程 (RTtap) 的时刻。后者被视为复极时间的金标准。我们还比较了下冲程期间 HMAP 和 TAP 首次达到其静止值 90% 的时间（RT90(HMAP)、RT90(tap)）。对于所有探索的位点，HMAP 下冲程紧随 TAP 下冲程，这是局部复极活动的表达。结果表明，HMAP 和 TAP 标记高度相关，并且标记 RTHMAP 和 RTeg (RT90(HMAP)) 都是 TAP 参考标记 RTtap (RT90(tap)) 的可靠估计。因此，HMAP 的下冲阶段包含评估复极时间的宝贵信息。
Unipolar electrograms (EGs) and hybrid (or unorthodox or unipolar) monophasic action potentials (HMAPs) are currently the only proposed extracellular electrical recording techniques for obtaining cardiac recovery maps with high spatial resolution in exposed and isolated hearts. Estimates of the repolarization times from the HMAP downstroke phase have been the subject of recent controversies. The goal of this paper is to computationally address the controversies concerning the HMAP information content, in particular the reliability of estimating the repolarization time from the HMAP downstroke phase. Three-dimensional numerical simulations were performed by using the anisotropic bidomain model with a region of short action potential durations. EGs, transmembrane action potentials (TAPs), and HMAPs elicited by an epicardial stimulation close or away from a permanently depolarized site were computed. The repolarization time was computed as the moment of EG fastest upstroke (RTeg) during the T wave, of HMAP fastest downstroke (RTHMAP), and of TAP fastest downstroke (RTtap). The latter was taken as the gold standard for repolarization time. We also compared the times (RT90(HMAP), RT90(tap)) when the HMAP and TAP first reach 90% of their resting value during the downstroke. For all explored sites, the HMAP downstroke closely followed the TAP downstroke, which is the expression of local repolarization activity. Results show that HMAP and TAP markers are highly correlated, and both markers RTHMAP and RTeg (RT90(HMAP)) are reliable estimates of the TAP reference marker RTtap (RT90(tap)). Therefore, the downstroke phase of the HMAP contains valuable information for assessing repolarization times.