The Impact of Potassium Dynamics on Cardiomyocyte Beating in Hemodialysis Treatment

TL;DR

This study explores how rapid drops in blood potassium during dialysis can harm heart function by affecting heart cell activity.

Contribution

The study is the first to use a mathematical model to investigate the impact of potassium dynamics on cardiomyocyte excitability during hemodialysis.

Findings

Excess decrease in plasma potassium prolongs depolarization in ventricular cells, temporarily increasing contraction force.

Rapid potassium decline activates funny channels in sinoatrial nodal cells, disrupting heart rhythm.

Low potassium levels reduce resting membrane potential in ventricular cells, leading to contractile dysfunction.

Abstract

Background: Observational studies of intermittent hemodialysis therapy have reported that the excess decrease in K+ concentration in plasma (KP) during treatment is associated with the destabilization of cardiac function. Elucidating the mechanism by which the decrease in KP impairs myocardial excitation is indispensable for a deeper understanding of prescription design. Methods: In this study, by using an electrophysiological mathematical model, we investigated the relationship between KP dynamics and cardiomyocyte excitability for the first time. Results: The excess decrease in KP during treatment destabilized cardiomyocyte excitability through the following events: (1) a decrease in KP led to the prolongation of the depolarization phase of ventricular cells due to the reduced potassium efflux rate of the Kr channel, temporarily enhancing contraction force; (2) an excess decrease in KP activated the transport of K+ and Na+ through the funny channel in sinoatrial nodal cells, disrupting automaticity; (3) the excess decrease in KP also resulted in a significant decrease in the resting membrane potential of ventricular cells, causing contractile dysfunction. Avoiding an excess decrease in KP during treatment contributed to the maintenance of cardiomyocyte excitability. Conclusions: The results of these mathematical analyses showed that it is necessary to implement personal prescription or optimal control of K+ concentration in dialysis fluid based on predialysis KP from the perspective of regulatory science in dialysis treatment.

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