Lloyd T R, Baldwin H S
Department of Pediatrics (Cardiology), University of Arizona College of Medicine, Tucson 85724.
Pediatr Res. 1990 Nov;28(5):425-8. doi: 10.1203/00006450-199011000-00001.
The conduction system functions of atrioventricular sequential contractions, atrioventricular delay, and coordination of ventricular contraction were examined in rat embryos at the earliest functional stage of cardiac development (before cardiac looping, n = 6) and shortly after looping (n = 15). Atrioventricular sequential contractions were observed in all embryos, and contractions appeared to originate in the left sinus horn. Atrioventricular delay was present in both prelooped (132 +/- 32 ms) and looped (141 +/- 15 ms) hearts. Before looping, contractions traveled from proximal ventricle to bulbus cordis, a distance of 253 +/- 27 microns, in 72 +/- 22 ms. After looping, contractions crossed an increased intraventricular distance (520 +/- 28 microns, p less than 0.005) in substantially less time (16 +/- 7 ms, p less than 0.005). Sinoatrial and atrioventricular nodal functions are emulated in both prelooped and looped hearts of early mammalian embryos, and His-Purkinje system function is emulated in looped hearts.
在心脏发育的最早功能阶段（心脏环化之前，n = 6）和环化后不久（n = 15）的大鼠胚胎中，研究了房室顺序收缩、房室延迟和心室收缩协调性的传导系统功能。在所有胚胎中均观察到房室顺序收缩，且收缩似乎起源于左窦角。在心脏环化前（132±32毫秒）和环化后（141±15毫秒）的心脏中均存在房室延迟。在心脏环化前，收缩从近端心室传至心球，距离为253±27微米，耗时72±22毫秒。在心脏环化后，收缩穿越增加的室内距离（520±28微米，p<0.005）所需时间显著缩短（16±7毫秒，p<0.005）。早期哺乳动物胚胎的心脏环化前和环化后心脏均模拟了窦房结和房室结功能，而环化后心脏模拟了希氏 - 浦肯野系统功能。
