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Increased GIRK channel activity prevents arrhythmia in mice with heart failure by enhancing ventricular

Xue An1,2, Hana Cho3

  • 1Department of Physiology, Sungkyunkwan University School of Medicine, Suwon, 16419, Korea.

Scientific Reports
|December 18, 2023
PubMed

Insights

In heart failure, GIRK channels are always active, preventing dangerous arrhythmias. Blocking these channels increases sudden cardiac death risk in mice with heart failure.

Area of Science:

  • Cardiology
  • Molecular Biology
  • Physiology

Background:

  • Sudden cardiac death due to ventricular arrhythmia is a primary cause of mortality in heart failure patients.
  • The precise mechanisms protecting against ventricular arrhythmias in heart failure remain incompletely understood.

Purpose of the Study:

  • To investigate the role of GIRK channels in preventing ventricular arrhythmias in a mouse model of heart failure.
  • To elucidate the mechanisms underlying constitutive GIRK channel activity in failing ventricles.

Main Methods:

  • Utilized a mouse model of heart failure induced by transverse aorta constriction.
  • Assessed GIRK channel activity and its regulation by M2 muscarinic acetylcholine receptors.
  • Investigated the effects of GIRK channel blockade using tertiapin-Q on cardiac electrophysiology and arrhythmia incidence.

Main Results:

  • GIRK channels exhibit constitutive activity in heart failure ventricles, unlike in normal ventricles.
  • Endogenously released acetylcholine tonically activates M2 muscarinic receptors, contributing to constitutive GIRK activity.
  • GIRK channel blockade with tertiapin-Q prolonged the QT interval and increased arrhythmia incidence in heart failure mice.

Conclusions:

  • Constitutive GIRK channel activity serves as a crucial protective mechanism against ventricular arrhythmias in heart failure.
  • These channels provide essential repolarizing currents, mitigating the risk of sudden cardiac death in failing hearts.

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