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Related Experiment Video

Updated: Sep 28, 2025

Analysis of Tubular Membrane Networks in Cardiac Myocytes from Atria and Ventricles

Analysis of Tubular Membrane Networks in Cardiac Myocytes from Atria and Ventricles

Published on: October 15, 2014

Automaticity in ventricular myocyte cell pairs with ephaptic and gap junction coupling.

Cheng Ly¹, Seth H Weinberg²

¹Department of Statistical Sciences and Operations Research, Virginia Commonwealth University, 1015 Floyd Avenue, Richmond, Virginia 23284, USA.

Chaos (Woodbury, N.Y.)

|April 2, 2022

Summary

Irregular heart rhythms can be caused by abnormal automaticity. This study reveals how cell coupling via potassium channels or narrow clefts can trigger heart automaticity and synchronization, offering new insights into cardiac arrhythmias.

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Analysis of Tubular Membrane Networks in Cardiac Myocytes from Atria and Ventricles

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Area of Science:

Cardiology
Computational Biology
Biophysics

Background:

Spontaneous electrical activity (automaticity) is crucial for heart function.
Irregular ventricular automaticity can lead to life-threatening cardiac arrhythmias.
Ephatic coupling through extracellular clefts has been proposed to influence automaticity.

Purpose of the Study:

To investigate the dynamics of coupled excitable cells incorporating both ephatic and gap junction coupling.
To explore mechanisms promoting automaticity and synchronization in cardiac cells.

Main Methods:

Computational modeling of coupled excitable cells.
Analysis of Hopf bifurcations to identify conditions for automaticity.
Exploration of parameter space including ion channel fractions and cleft volume.

Main Results:

Automaticity and synchronization robustly emerge by increasing inward rectifying potassium current (I_K1) at the junctional membrane or decreasing cleft volume.
Heterogeneity in potassium channel distribution can lead to varied automaticity and synchronization outcomes.
Gap junction coupling has minimal impact on the emergence of automaticity.

Conclusions:

Ephatic coupling, influenced by potassium channels and cleft geometry, plays a significant role in cardiac automaticity.
Findings provide insights into novel mechanisms underlying spontaneous activity and potential triggers for arrhythmias.
This research contributes to understanding the complex dynamics of cardiac electrical activity.