February 1, 1997Pacing and Clinical Electrophysiology
Polarity Reversal Improves Defibrillation Efficacy in Patients Undergoing Transvenous Cardioverter Defibrillator Implantation with Biphasic Sbocks
Key result
Reversed polarity (distal electrode as anode) significantly reduced the defibrillation threshold compared to initial polarity (11.1 ± 5.7 J vs 13.3 ± 5.8 J; P=0.033) during ICD implantation.
Why the study?
Does polarity reversal (distal electrode as anode) reduce defibrillation threshold energy requirements in patients undergoing transvenous cardioverter defibrillator implantation with biphasic shocks?
Population
27 patients undergoing implantation of nonthoracotomy transvenous cardioverter defibrillators with biphasic…
Comparison
Reversed polarity for biphasic shock… vs Initial polarity for biphasic shock defibrillation
Design
RCT, Randomized to initial DFT testing with 'initial' or 'reversed' polarity
Follow-up
Acute (during implantation)
Authors
Discussion
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Implication
Reversed polarity may be adopted initially in transvenous ICD implantation to lower energy needs; confirms benefit for biphasic shocks in this RCT.
Study Design
Type
RCT (n=27)
Randomization
randomized
Structured PICO
Does polarity reversal (distal electrode as anode) reduce defibrillation threshold energy requirements in patients undergoing transvenous cardioverter defibrillator implantation with biphasic shocks?
P
Population
27 patients undergoing transvenous cardioverter defibrillator implantation with biphasic shocks.
I
Intervention
Reversed polarity (distal electrode = anode) for biphasic shock defibrillation
C
Comparator
Initial polarity (distal electrode = cathode) for biphasic shock defibrillation
O
Outcome
Defibrillation threshold (DFT) energy requirementsurrogate
Main Result
Effect estimate: 17% reduction
Absolute Event Rate: 11.1% vs 13.3%
p-value: p=0.033
Changing electrode polarity to distal anode in transvenous implantable defibrillators with biphasic shocks significantly reduces defibrillation energy requirements.
Cite This Study
Schauerte et al. (1997) conducted an RCT in Transvenous cardioverter defibrillator implantation (n=27). Reversed polarity (distal electrode = anode) vs. Initial polarity (distal electrode = cathode) was evaluated on Defibrillation threshold (DFT) energy requirement (17% reduction, p=0.033). Reversed polarity (distal electrode as anode) significantly reduced the defibrillation threshold compared to initial polarity (11.1 ± 5.7 J vs 13.3 ± 5.8 J; P=0.033) during ICD implantation.