Emerging patterns of cardiac conduction in the chick embryo: Waveform analysis with photodiode array-based optical imaging
Emerging patterns of cardiac conduction in the chick embryo: Waveform analysis with photodiode array-based optical imaging
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DOI：
10.1002/dvdy.20338
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发表时间：
2005-06-01
影响因子：
2.5
通讯作者：
Rosenbaum, D
中科院分区：
文献类型：
--
作者：
Rothenberg, F;Watanabe, M;Rosenbaum, D
研究发育中的心脏传导系统的主要困难来自于胚胎心脏非常小(<；2 mm)和心脏激活相对较快(<；8ms)。本研究的目的是利用一种基于光电二极管阵列的光学标测检测方法，研究鸡胚胎心脏传导系统在围绝育期的电生理。以前的工作表明，在鸡胚中，在室间隔时，心室激活模式发生了从未成熟的基底部到心尖部到成熟的心尖到基底部的转换。我们的目标是更详细地绘制激活图，以确定在这些特定阶段的一个或多个房室传导的活跃途径。对预切开的心脏(n=10)的分析表明，最新的心房激动发生在最早的左心室底部心室激动部位的正上方。对分离后心脏(n=11)的分析表明，心尖到心底的传导与通过成熟的His-Purkinje系统激活相一致。在间隔期间对心脏的评估显示，心室激活模式是一个逐渐转变的过程，而不是突然的“转换”。预置心脏体外起搏的室间传导较自发性起搏显著减慢(自发起搏61.7 cm/s+/-9 cm/s，起搏36.5 cm/s+/-10 cm/s)。更详细的标测显示，在间隔前，心室肌的激活模式与左侧房室交界处的直接房室心肌连接是一致的；然而，在间隔之前就有了心室内优先传导途径的功能证据。(C)2005年Wiley-Liss，Inc.
Major difficulties investigating the developing cardiac conduction system stem from that the embryonic heart is extremely small (< 2 mm) and cardiac activation is relatively rapid (< 8 msec). The objective of this study was to investigate the electrophysiology of the embryonic chick cardiac conduction system at periseptation stages with a photodiode array-based detection method of optical mapping capable of high spatial and temporal resolution. Previous work indicated that, in chicken embryos, a switch occurs in ventricular activation pattern from immature base-to-apex to mature apex-to-base pattern at the time of ventricular septation. It was our aim to map activation in more detail to identify the active pathway or pathways of atrioventricular conduction at these particular stages. Analysis of preseptated hearts (n = 10) showed that the latest atrial activation took place just above the site of the earliest ventricular activation at the ventral left ventricular base. Analysis of postseptated hearts (n = 11) showed apex-to-base conduction consistent with activation through the maturing His-Purkinje system. Evaluation of hearts during septation revealed a gradual transition of ventricular activation patterns rather than an abrupt "switch." External pacing of preseptated hearts revealed significant slowing of interventricular conduction compared with spontaneous beats (spontaneous, 61.7 cm/sec +/- 9 cm/sec vs. paced, 36.5 cm/sec +/- 10 cm/sec). The more detailed mapping revealed that, before septation, the pattern of activation of the ventricular myocardium is consistent with direct atrial-ventricular myocardial connections at the left lateral atrioventricular junction; however, functional evidence for a preferential conduction pathway within the ventricles was present before septation. (c) 2005 Wiley-Liss, Inc.