Electrolyte disturbances differentially regulate sinoatrial node and pulmonary vein electrical activity: A contribution to hypokalemia- or hyponatremia-induced atrial fibrillation

Yen Yu Lu, Chen Chuan Cheng, Yao Chang Chen, Yung-Kuo Lin, Shih Ann Chen, Yi-Jen Chen

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17 Citations (Scopus)


Background: Hypokalemia and hyponatremia increase the occurrence of atrial fibrillation. Sinoatrial nodes (SANs) and pulmonary veins (PVs) play a critical role in the pathophysiology of atrial fibrillation. Objective: The purpose of this study was to evaluate whether electrolyte disturbances with low concentrations of potassium ([K+]) or sodium ([Na+]) modulate SAN and PV electrical activity and arrhythmogenesis, and to investigate potential underlying mechanisms. Methods: Conventional microelectrodes were used to record electrical activity in rabbit SAN and PV tissue preparations before and after perfusion with different low [K+] or [Na+], interacting with the Na+-Ca2+ exchanger inhibitor KB-R7943 (10 μΜ). Results: Low [K+] (3.5, 3, 2.5, and 2 mM) decreased beating rates in PV cardiomyocytes with genesis of delayed afterdepolarizations (DADs), burst firing, and increased diastolic tension. Low [K+] (3.5, 3, 2.5, and 2 mM) also decreased SAN beating rates, with genesis of DADs. Low [Na+] increased PV diastolic tension, DADs, and burst firing, which was attenuated in the co-superfusion with low [K+] (2 mM). In contrast, low [Na+] had little effect on SAN electrical activities. KB-R7943 (10 μΜ) reduced the occurrences of low [K+] (2 mM)- or low [Na+] (110 mM)-induced DAD and burst firing in both PVs and SANs. Conclusion: Low [K+] and low [Na+] differentially modulate SAN and PV electrical properties. Low [K+]- or low [Na+]-induced slowing of SAN beating rate and genesis of PV burst firing may contribute to the high occurrence of atrial fibrillation during hypokalemia or hyponatremia.

Original languageEnglish
Pages (from-to)781-788
JournalHeart Rhythm
Publication statusPublished - 2016



  • Atrial fibrillation
  • Hypokalemia
  • Hyponatremia
  • Pulmonary vein
  • Sinoatrial node

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

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