低血钾可引起各种心律失常,但引起心脏传导阻滞者较为少见,我们遇到5例,现报告如下。讨论钾是心肌细胞内主要的正离子,细胞内外的K~+浓度差是形成静息膜电位的基础。血钾浓度的改变主要通过影响心肌细胞的静息电位而影响心脏的活动。根据Nernst公式膜电位=61.5log[K]_0/[K]_i([K]_i、[K]_0分别为细胞内、外K~+浓度),低血钾时,由于[K]_0减小,因此膜电位负值增大,呈现“过极化状态”,心肌细胞不易达到应激阈值,产生“过极化阻滞”。此乃急性缺钾心脏传导阻滞发生之机理。而慢性缺钾时,常伴有细胞内缺钾,[K]_i减小,膜电位负值亦减小,呈“极 Hypokalemia can cause a variety of arrhythmias, but caused by heart block is rare, we encountered 5 cases, are as follows. Discussion Potassium is the main positive ion in cardiomyocytes. The difference of K ~ + concentration inside and outside the cells is the basis for the formation of resting membrane potential. Changes in serum potassium concentration mainly affect cardiomyocyte activity by affecting the resting potential of cardiomyocytes. According to the Nernst formula, the membrane potential = 61.5log [K] _0 / [K] _i ([K] _i, [K] _0 respectively, intracellular and extracellular K ~ Small, so the negative membrane potential increased, showing “over-polarization state”, myocardial cells difficult to reach the stress threshold, resulting in “over-polarization block.” This is the mechanism of acute potassium deficiency heart block. Chronic potassium deficiency, often accompanied by intracellular potassium deficiency, [K] _i decreased, negative membrane potential also decreased, was "pole