Document Detail

Cerebral oxygenation during defibrillator threshold testing of implantable cardioverter defibrillators.
MedLine Citation:
PMID:  15955185     Owner:  NLM     Status:  MEDLINE    
BACKGROUND: The induction of ventricular fibrillation (VF) during defibrillator threshold testing of implantable cardioverter defibrillators (ICD) provokes global cerebral hypoperfusion and impaired oxygen delivery. Limited data are available on the neurophysiological effects of defibrillator threshold testing. Near infrared spectroscopy (NIRS) can noninvasively measure changes in specific chromophores, which reflect cerebral oxygenation at the intravascular and mitochondrial levels. We performed a prospective trial using NIRS to analyze cerebral cortical oxygenation during defibrillator threshold testing. METHODS: Eleven patients (men = 9; age = 64 +/- 11 years: LVEF = 44 +/- 11%) underwent subpectoral ICD implantation and defibrillator threshold testing under general anesthesia. A NIRO 300 spectrometer was used to measure the absolute changes in the concentrations of oxyhemoglobin, de-oxyhemoglobin, and cytochrome c oxidase copper moiety during each procedure. The mean arterial blood pressure was monitored simultaneously. RESULTS: The mean number of defibrillator threshold tests was two (range 2-6). Twenty-six episodes of VF (duration 13.1 +/- 9.7 seconds; cycle length 230.2 +/- 20.8 ms) and two episodes of VT (duration 15 +/- 2.8 seconds; cycle length 320 +/- 11.3 ms) were induced. Each episode of VF and VT resulted in a decrease in the mean arterial blood pressure to 23.9 +/- 7.5 mmHg (p < or = 0.05) and oxyhemoglobin (-4.2 +/- 1.7 micromol/L; p < or = 0.05) and an increase in de-oxyhemoglobin (2.7 +/- 1.4 micromol/L). There was no change in the cytochrome c oxidase copper moiety redox status (0.09 +/- 0. 30 micromol/L). CONCLUSION: Our results suggest that impaired oxygen delivery during induced VF and VT does not affect oxygen availability at the cellular intra-mitochondrial level.
Elizabeth McNeill; Roy E Gagnon; James E Potts; John A Yeung-Lai-Wah; Charles R Kerr; Shubhayan Sanatani
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Publication Detail:
Type:  Clinical Trial; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Pacing and clinical electrophysiology : PACE     Volume:  28     ISSN:  0147-8389     ISO Abbreviation:  Pacing Clin Electrophysiol     Publication Date:  2005 Jun 
Date Detail:
Created Date:  2005-06-15     Completed Date:  2006-01-19     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  7803944     Medline TA:  Pacing Clin Electrophysiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  528-33     Citation Subset:  IM    
Division of Cardiology, Department of Medicine, The University of British Columbia, Vancouver, BC, Canada.
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MeSH Terms
Brain / metabolism*
Defibrillators, Implantable*
Middle Aged
Oxygen / metabolism*
Prospective Studies
Spectroscopy, Near-Infrared*
Reg. No./Substance:

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