# 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.

## Key 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.