Ikeda K
Bull Tokyo Med Dent Univ. 1980 Dec;27(4):151-7.
This study was undertaken to determine the effect of hypoxia on the cable properties of the canine ventricular muscle, employing a single sucrose gap method. Hypoxia caused the internal longitudinal resistance, Ri, to increase by 25% (P smaller than 0.02) and the length constant, lambda, to decrease by 13% (P smaller than 0.05), significantly. The control values of Ri and lambda were 198 +/-76 omega cm and 0.81 +/- 0.15 mm (mean +/- SD, n=5, respectively. The membrane resistance, Rm, (control; 3026 +/- 581 omega cm2) decreased by 6%. The membrane capacitance and the time constant were not affected significantly. It was also examined whether the increase in Ri during hypoxia could be caused by hyperkalemia or acidosis, which are known to occur during hypoxia. The results showed that Ri was unchanged under acidosis (pH 6.1) to high K+ concentration (10.8 mM), thus suggesting the direct effect of hypoxia on Ri. These results suggest that the changes in the cable properties play important roles in the genesis of arrhythmias during hypoxia.
本研究采用单蔗糖间隙法，旨在确定缺氧对犬心室肌电缆特性的影响。缺氧导致内部纵向电阻Ri增加25%（P<0.02），长度常数λ降低13%（P<0.05），差异显著。Ri和λ的对照值分别为198±76Ω·cm和0.81±0.15mm（均值±标准差，n = 5）。膜电阻Rm（对照值；3026±581Ω·cm²）降低了6%。膜电容和时间常数未受到显著影响。研究还探讨了缺氧期间Ri的增加是否可能由高钾血症或酸中毒引起，已知这些情况会在缺氧期间发生。结果表明，在酸中毒（pH 6.1）至高钾浓度（10.8 mM）条件下，Ri未发生变化，因此提示缺氧对Ri有直接影响。这些结果表明，电缆特性的变化在缺氧期间心律失常的发生中起重要作用。
