Cupisti A, Galetta F, Caprioli R, Morelli E, Tintori G C, Franzoni F, Lippi A, Meola M, Rindi P, Barsotti G
Dipartimento di Medicina Interna, Università di Pisa, Pisa, Italia.
Nephron. 1999 Jun;82(2):122-6. doi: 10.1159/000045387.
This study was planned to clarify the mechanism(s) by which hemodialysis increases the QTc dispersion, a marker of risk of ventricular arrhythmias. To this aim, 10 uremic patients, without any relevant heart diseases, underwent two different types of hemodialysis schedules. In the first, 1 h of isolated high rate ultrafiltration preceded the standard diffusive procedure. In the second, during the first hour of standard bicarbonate hemodialysis, the decrease of plasma potassium concentration was prevented by increasing K+ concentration in the dialysate, according to its pre dialysis plasma levels. During the high rate ultrafiltration period, together with ECG signs of increased sympathetic nervous system activity and catecholamines secretion, the QTc dispersion did not change significantly. Instead, an evident increment was observed 1 h after the start of the diffusive hemodialysis, then slowly progressing until the end of the dialysis and finally returning to the pre dialysis values within 2 h after the end of the session. To the contrary, the increase of the QTc dispersion was totally blunted during a standard hemodialysis procedure in absence of plasma K+ decrease, but appeared again when the K+ dialysate fluid concentration was restored to 2 mmol/l. This study provides evidence that the increase of QTc dispersion occurring on hemodialysis is mainly related to the diffusive process, more precisely to the K+ removal. This is one more reason to focus attention on K+ removal rate especially when hemodialysis treatment is given in uremics affected by cardiac diseases with high risk of arrhythmias.
本研究旨在阐明血液透析增加QTc离散度（室性心律失常风险标志物）的机制。为此，10名无任何相关心脏疾病的尿毒症患者接受了两种不同类型的血液透析方案。第一种方案是在标准弥散程序之前先进行1小时的单纯高流量超滤。第二种方案是在标准碳酸氢盐血液透析的第一个小时期间，根据透析前血浆水平，通过提高透析液中钾离子浓度来防止血浆钾浓度降低。在高流量超滤期间，尽管出现了交感神经系统活动增加和儿茶酚胺分泌增加的心电图表现，但QTc离散度并未显著改变。相反，在弥散性血液透析开始1小时后观察到QTc离散度明显增加，然后缓慢进展直至透析结束，最终在透析结束后2小时内恢复到透析前值。相反，在标准血液透析过程中，当不存在血浆钾降低时，QTc离散度的增加完全被抑制，但当透析液中钾离子浓度恢复到2 mmol/L时，QTc离散度又再次出现增加。本研究提供了证据表明，血液透析时发生的QTc离散度增加主要与弥散过程有关，更确切地说是与钾离子清除有关。这是在为有高心律失常风险的心脏病尿毒症患者进行血液透析治疗时，尤其要关注钾离子清除率的又一个原因。
