Repetitive endocardial focal discharges during ventricular fibrillation with prolonged global ischemia in isolated rabbit hearts

Tsu Juey Wu*, Shien-Fong Lin, Yu Cheng Hsieh, Yung Tsung Chiu, Chih Tai Ting

*Corresponding author for this work

Research output: Contribution to journalArticle

5 Scopus citations

Abstract

Background: Ventricular fibrillation (VF) during prolonged (>5 min) global ischemia (GI) could be due to repetitive endocardial focal discharges (REFDs). This hypothesis was tested in isolated rabbit hearts. Methods and Results: With optical mapping, simultaneous endocardial (left ventricle, LV) and epicardial (both ventricles) activations during VF with prolonged GI were studied (protocol I, 8 hearts). Lugol solution was applied to the LV endocardium in additional 5 hearts after 5-min GI (protocol II). During prolonged GI, sustained VF (>30 s) was successfully induced in 7 protocol I hearts. The dominant frequency of summed optical signals at the LV endocardium was higher than at the epicardium (P<0.05). Mapping data showed that after 5-min GI, REFDs were present in >90% for recording time. There were 18 windows of optical recording showing spontaneous VF termination. In 10, once REFDs ceased, the VF episode terminated immediately. Electrical defibrillation was also performed on 3 hearts. Eight shocks showed early VF recurrence after successful defibrillation. REFDs were consistently involved in the initiation period of recurrence. In protocol II, Lugol subendocardial ablation diminished REFD genesis during re-induced VF. These VF episodes were all non-sustained. Conclusions: REFDs at the LV endocardium were important for both VF maintenance and post-shock recurrence during prolonged GI in this model.

Original languageEnglish
Pages (from-to)1803-1811
Number of pages9
JournalCirculation Journal
Volume73
Issue number10
DOIs
StatePublished - 1 Oct 2009

Keywords

  • Endocardium
  • Fibrillation
  • Ischemia
  • Mapping
  • Ventricles

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