Document Detail

Effect of electrode configuration and capacitor size on internal atrial defibrillation threshold using leads currently used for ventricular defibrillation.
MedLine Citation:
PMID:  10387142     Owner:  NLM     Status:  MEDLINE    
BACKGROUND: Previous studies have shown that endocardial atrial defibrillation, using lead configurations specifically designed for ventricular defibrillation, is feasible but the substantial patient discomfort might prevent the widespread use of the technique unless significant improvements in shock tolerability are achieved. It has been suggested that the peak voltage or the peak current but not the total energy delivered determines the patient pain perception and therefore, lower defibrillating voltage and current achieved with modifications in lead and waveforms may increase shock tolerability. This study was undertaken to evaluate the effect, on the atrial defibrillation threshold (ADFT), of the addition of a patch electrode (mimicking the can electrode) to the right ventricle (RV)-superior vena cava (SVC) lead configuration. The influence of capacitor size on ADFT using the RV-SVC+skin patch configuration was also assessed.
METHODS: In 10 patients (pts) (Group 1) cardioversion thresholds were evaluated using biphasic shocks in two different configurations: 1) right ventricle (RV) to superior vena cava (SVC); 2) RV to SVC+skin patch. In a second group of twelve patients (Group 2) atrial defibrillation thresholds of biphasic waveforms that differed with the total capacitance (90 or 170 microF) were assessed using the RV to SVC+skin patch configuration.
RESULTS: In Group 1 AF was terminated in 10/10 pts (100 %) with both configurations. There was no significant difference in delivered energy at the defibrillation threshold between the two configurations (7.1 +/- 5.1 J vs 7.1 +/- 2.6 J; p < 0.05). In group 2 AF was terminated in 12/12 pts (100%) with both waveforms. The 170 microF waveform provided a significantly lower defibrillating voltage (323.7 +/- 74.6 V vs 380 +/- 70.2 V; p < 0.03) and current (8.1 +/- 2.7 A vs 10.0 +/- 2.3 A; p < 0.04) than the 90 microF waveform. All pts, in both groups, perceived the shock of the lowest energy tested (180 V) as painful or uncomfortable.
CONCLUSIONS: The addition of a patch electrode to the RV-SVC lead configuration does not reduce the ADFT. Shocks from larger capacitors defibrillate with lower voltage and current but pts still perceive low energy subthreshold shocks as painful or uncomfortable.
R Neri; P Palermo; A S Cesario; D Baragli; E Amici; M T Laudadio; A De Rosa; F DeSeta; L Mongeon; G Gambelli
Publication Detail:
Type:  Clinical Trial; Journal Article    
Journal Detail:
Title:  Journal of interventional cardiac electrophysiology : an international journal of arrhythmias and pacing     Volume:  3     ISSN:  1383-875X     ISO Abbreviation:  J Interv Card Electrophysiol     Publication Date:  1999 Jul 
Date Detail:
Created Date:  1999-09-24     Completed Date:  1999-09-24     Revised Date:  2014-07-29    
Medline Journal Info:
Nlm Unique ID:  9708966     Medline TA:  J Interv Card Electrophysiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  149-53     Citation Subset:  IM    
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MeSH Terms
Atrial Fibrillation / therapy*
Differential Threshold
Electric Countershock / adverse effects,  instrumentation*,  methods*
Equipment Design
Middle Aged
Pain / etiology
Treatment Outcome
Ventricular Fibrillation / therapy*

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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