Role of slow delayed rectifying potassium current in dynamics of repolarization and electrical memory in swine ventricles

Linyuan Jing, Kathleen Brownson, Abhijit Patwardhan

Research output: Contribution to journalArticlepeer-review

6 Scopus citations

Abstract

Dynamics of repolarization, quantified as restitution and electrical memory, impact conduction stability. Relatively less is known about role of slow delayed rectifying potassium current, I Ks, in dynamics of repolarization and memory compared to the rapidly activating current I Kr. Trans-membrane potentials were recorded from right ventricular tissues from pigs during reduction (chromanol 293B) and increases in I Ks (mefenamic acid). A novel pacing protocol was used to explicitly control diastolic intervals to quantify memory. Restitution hysteresis, a consequence of memory, increased after chromanol 293B (loop thickness and area increased 27 and 38 %) and decreased after mefenamic acid (52 and 53 %). Standard and dynamic restitutions showed an increase in average slope after chromanol 293B and a decrease after mefenamic acid. Increase in slope and memory are hypothesized to have opposite effects on electrical stability; therefore, these results suggest that reduction and enhancement of I Ks likely also have offsetting components that affect stability.

Original languageEnglish
Pages (from-to)185-193
Number of pages9
JournalJournal of Physiological Sciences
Volume64
Issue number3
DOIs
StatePublished - May 2014

Bibliographical note

Funding Information:
Acknowledgement Supported by grants from the National Science Foundation (0730450, 0814194) and the Commonwealth of Kentucky.

Keywords

  • Action potential duration
  • Cardiac memory
  • Hysteresis
  • Restitution
  • Slow delayed rectifier potassium current
  • Ventricular arrhythmia

ASJC Scopus subject areas

  • Physiology

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