Related Experiment Video
Updated: Jul 9, 2026
Assessment of Sarcoplasmic Reticulum Calcium Reserve and Intracellular Diastolic Calcium Removal in Isolated Ventricular Cardiomyocytes
Published on: September 18, 2017
Calcium and potassium changes during haemodialysis alter ventricular repolarization duration: in vivo and in silico
Stefano Severi1, Eleonora Grandi, Chiara Pes
1Biomedical Engineering Laboratory, D.E.I.S., University of Bologna, Via Venezia 52, I-47023 Cesena, Italy. stefano.severi@unibo.it
Insights
Low calcium and potassium levels during hemodialysis (HD) can prolong the QT interval (QTc), increasing arrhythmia risk. Careful dialysate management is crucial to prevent dangerous cardiac repolarization changes in HD patients.
Area of Science:
- Cardiology
- Nephrology
- Computational Biology
Background:
- Ventricular repolarization duration, measured by QT interval, is altered in hemodialysis (HD) patients.
- The exact mechanisms and direction of these QT interval changes remain unclear.
Purpose of the Study:
- To investigate the impact of varying dialysate calcium (Ca2+) and potassium (K+) levels on QT interval duration (QTc) in HD patients.
- To assess cellular-level electrophysiological changes using a cardiomyocyte action potential model to explain observed QTc alterations.
Main Methods:
- Tested different dialysate Ca2+ and K+ concentrations to observe their effect on end-HD plasma levels and QTc.
- Employed a human cardiomyocyte action potential (AP) model for in silico analysis of Ca2+ and K+ effects on QTc.
Main Results:
- QTc was significantly prolonged in HD patients with lower Ca2+ (1.25 mM vs 2 mM) and lower K+ (2 mM vs 3 mM) dialysate concentrations.
- In silico analysis confirmed that reduced K+ and Ca2+ prolonged ventricular AP duration, correlating with QTc variations.
- Simulations predicted critically prolonged AP and QT intervals when both low K+ and Ca2+ were present concurrently, indicating a potential arrhythmogenic factor.
Conclusions:
- Computational modeling of ventricular AP duration is valuable for predicting QTc changes due to simultaneous K+ and Ca2+ variations.
- Dialysate Ca2+ levels should be managed to avoid critical reductions in serum Ca2+, particularly in patients at risk of end-dialysis hypokalemia.
Background:
Alterations of ventricular repolarization duration, as measured by the QT interval, are frequently observed in haemodialysis (HD) patients. The nature and the sign of these changes are not yet fully understood.
Methods:
Different dialysate K(+) and Ca(2+) levels, leading to different end-HD plasma concentrations in the patient, have been tested in the present study in terms of their impact on QTc. A model of the human cardiomyocyte action potential (AP) has been used to assess in silico whether the changes in Ca(2+) and K(+) were able to justify at the cellular level the observed alterations of QTc.
Results:
QTc was prolonged in HDs with low (1.25 mM) versus high (2 mM) Ca(2+) (424 +/- 33 versus 400 +/- 28 ms, P < 0.05) and in HDs with low (2 mM) versus high (3 mM) K(+) (420 +/- 35 versus 399 +/- 36 ms, P < 0.05). These alterations were confirmed at the cellular level by computational analysis showing prolongation of ventricular AP at low K(+) and low Ca(2+) at the same extent of the measured QTc variations. Numerical simulation predicted a critically long AP (and QT) when considering low K(+) and Ca(2+) simultaneously, suggesting the concurrent lowering of Ca(2+) and K(+) as a potential arrhythmogenic factor.
Conclusions:
Numerical simulations of the ventricular AP may be useful to quantitatively predict the complex dependence of AP duration on simultaneous changes in Ca(2+) and K(+). Moreover, Ca(2+) content in the dialysate should be designed not to critically lower serum Ca(2+), especially in sessions at risk of end-dialysis hypokalaemia.
More Related Videos
07:42Contractions of Human-iPSC-derived Cardiomyocyte Syncytia Measured with a Ca-sensitive Fluorescent Dye in Temperature-controlled 384-well Plates
Published on: October 18, 2018
10:01High-Throughput Optical Controlling and Recording Calcium Signal in iPSC-Derived Cardiomyocytes for Toxicity Testing and Phenotypic Drug Screening
Published on: March 31, 2022
Related Concept Videos
01:28Antihypertensive Drugs: Potassium-Sparing Diuretics
01:20Antiarrhythmic Drugs: Class IV Agents as Calcium Channel Blockers
Verapamil, a calcium channel blocker, inhibits calcium movement across myocardial cell membranes and vascular smooth muscle. This results in the dilation of coronary and...
01:12Antiarrhythmic Drugs: Class III Agents as Potassium Channel Blockers
01:30Cardiac Action Potential
The cardiac action potential process involves a series of phases characterized by the movement of ions across the cardiac cell membranes, leading to the depolarization and repolarization of the cardiac myocytes.
Ionic Basis of Cardiac Action Potentials
01:26Regulation of Sodium and Potassium
Sodium Regulation
Sodium ions make up approximately 90% of extracellular cations, with a normal blood plasma concentration of 136–148 mEq/L. A decrease in blood volume and pressure triggers the release of renin from granular cells in the juxtaglomerular complex (JGC), primarily in...
01:24Roles of Electrolytes: Sodium and Potassium