Electrophysiological characteristics of complex fractionated electrograms and high frequency activity in atrial fibrillation

Shih Lin Chang, Yao Chang Chen, Chiao Po Hsu, Yu Hsun Kao, Yung Kuo Lin, Yenn Jiang Lin, Tsu Juey Wu, Shih Ann Chen, Yi Jen Chen

Research output: Contribution to journalArticlepeer-review

16 Citations (Scopus)

Abstract

Background It is unclear whether atrial substrate with complex fractionated electrograms (CFAEs) is related to arrhythmogenesis. This study aimed to investigate the electrophysiology in CFAE and high dominant frequency (DF) areas. Methods and results Atrial fibrillation (AF) was induced by rapid atrial pacing in heart failure (HF) rabbits (4 weeks after coronary artery ligation). Real-time substrate mapping, multielectrode array, and monophasic action potential recordings were used to study areas of CFAE and DF. Conventional microelectrode and western blot were used to record the action potentials (APs) and protein expression in isolated tissue preparations. CFAE site with high DF had the most depolarized resting membrane potential, highest incidence of early and delayed afterdepolarizations, and steepest maxima slope of 90% of AP duration (APD90) restitution curve (RC) compared to CFAE site with low DF or non-CFAE sites. CFAE site with high DF exhibited the slowest conduction velocity and shortest wavelength than the other areas. Upregulation of the Na+-Ca2 + exchanger (NCX), apamin-sensitive small-conductance Ca2 +-activated K+ channel type 2 (SK2) and sarcoplasmic reticulum Ca2 +-ATPase, and downregulation of the Kir2.1 were found at CFAE site with high DF compared to that observed in the 3 other areas. Inhibition of the NCX and SK channels prolonged the APD 90, flattened the maximum slope of RC, and suppressed AF. Conclusions CFAE site with high DF had an arrhythmogenic property differing significantly from the other areas of LA in an HF rabbit model, which may contribute to the genesis of AF.

Original languageEnglish
Pages (from-to)2289-2299
Number of pages11
JournalInternational Journal of Cardiology
Volume168
Issue number3
DOIs
Publication statusPublished - Oct 3 2013

Keywords

  • Atrial fibrillation
  • Complex fractionated electrograms
  • Dominant frequency
  • Heart failure

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine
  • Medicine(all)

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