液态媒质中鸡胚心脏瞬间心电向量的综合

目的和方法在电导率不同的2种液态媒质中,采集60个5日龄鸡胚心脏2组相反方向上若干离场源不同距离的测试点心电图,分别比较相同媒质中相反方向上相同距离点的心电图形态和R(r)波振幅,判断该单腔心瞬间心电向量综合的可能性.结果无论是高电导率的生理盐水,还是低电导率的蒸馏水,相同媒质相反方向相同距离点上的心电图皆为正立,其R(r)波振幅的差异不显著(P>0.05);心电在高电导率液态媒质中的衰减幅度远大于在低电导率的液态中的衰减幅度.结论单腔心相反方向的心肌除极所形成的瞬间心电向量可能由于心腔内高电导率血液的衰减效应而无法实现跨越心腔的相互综合.任一瞬间的心电活动可能无法用单一的综合心电向量来表示.

Synthesis of the resultant instantaneous cardiac vector of chick embryonic heart in liquid medium

Objective and Method The ECGs of 60 hearts of 5-day chick embryos immersed in normal saline water or distilled water were recorded at 5 points with different distances in 4 directions perpendicular to one another. Comparison of the pattem and amplitude of ECG was made between every 2 points with the same distance to the heart in 2 opposite directions, to determine the fashion of resultant synthesis of cardiac vectors of single chamber heart. Results The ECGs at every 2 points in 2 opposite directions with the same distance to the heart immersed in the same liquid medium were both upper standing, without significant difference between their amplitude of R(r) waves (P>0.05). Conclusion No synthesis of instantaneous cardiac vectors occurred in 2 opposite directions across chambers during single-chamber cardiac depolarization, possibly because of the offset effect of blood in chamber due to its high conductance it is impossible to synthesize the instantaneous cardiac vector into a single vector at any moment