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Updated: Nov 7, 2025

Parallel Measurement of Circadian Clock Gene Expression and Hormone Secretion in Human Primary Cell Cultures
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Distinct circadian mechanisms govern cardiac rhythms and susceptibility to arrhythmia

Edward A Hayter1, Sophie M T Wehrens2, Hans P A Van Dongen3,4

  • 1Centre for Biological Timing, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK.

Nature Communications
|May 1, 2021
PubMed

Insights

The heart

Area of Science:

  • Cardiology
  • Chronobiology
  • Molecular Biology

Background:

  • The heart's electrical activity follows a 24-hour rhythm, influencing arrhythmia occurrence.
  • Circadian rhythms are known to affect physiological processes, including cardiac function.

Purpose of the Study:

  • To investigate how circadian clocks in the brain and heart regulate daily rhythms in sinoatrial (SA) and atrioventricular (AV) node activity.
  • To determine the time-of-day dependent susceptibility to ventricular arrhythmia.
  • To explore the impact of altered circadian inputs on cardiac conduction.

Main Methods:

  • Investigated circadian clock mechanisms in cardiac tissues.
  • Analyzed autonomic nervous system influences on cardiac nodes.
  • Examined electrophysiological properties of the SA and AV nodes under varying circadian conditions.

Main Results:

  • Circadian clocks in the brain and heart establish daily rhythms in SA and AV node activity.
  • A time-of-day dependent susceptibility to ventricular arrhythmia was observed.
  • Differential circadian input balance to SA and AV nodes was identified, leading to conduction system sensitivity.

Conclusions:

  • Circadian control is functionally segregated across the heart's conduction system.
  • Abrupt shifts in routine can decouple cardiac conduction, increasing arrhythmia risk.
  • Understanding these circadian mechanisms is crucial for managing cardiac arrhythmias.

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