Optimal small-capacitor biphasic waveform for external defibrillation : Influence of phase-1 tilt and phase-2 voltage

Biphasic waveforms have been reported to be more efficacious than monophasic waveforms for external defibrillation. This study examined the optimal phase-1 tilts and phase-2 leading-edge voltages with small capacitors (60 and 20 microF) for external defibrillation. We also assessed the ability of th...

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Bibliographic Details
Published in:Circulation (New York, N.Y.) N.Y.), 1998-12, Vol.98 (22), p.2487-2493
Main Authors: YAMANOUCHI, Y, BREWER, J. E, MOWREY, K. A, DONOHOO, A. M, WILKOFF, B. L, TCHOU, P. J
Format: Article
Language:English
Subjects:
Animals
Biological and medical sciences
Diseases of the cardiovascular system
Electric Conductivity
Electric Countershock - instrumentation
Medical sciences
Models, Cardiovascular
Radiotherapy. Instrumental treatment. Physiotherapy. Reeducation. Rehabilitation, orthophony, crenotherapy. Diet therapy and various other treatments (general aspects)
Swine
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Summary:Biphasic waveforms have been reported to be more efficacious than monophasic waveforms for external defibrillation. This study examined the optimal phase-1 tilts and phase-2 leading-edge voltages with small capacitors (60 and 20 microF) for external defibrillation. We also assessed the ability of the "charge-burping" model to predict the optimal waveforms. Two groups of studies were performed. In group 1, 9 biphasic waveforms from a combination of 3 phase-1 tilt values (30%, 50%, and 70%) and 3 phase-2 leading-edge voltage values (0.5, 1.0, and 1.5 times the phase-1 leading-edge voltage, V1) were tested. Phase-2 pulse width was held constant at 3 ms in all waveforms. Two separate 60- microF capacitors were used in each phase. The energy value that would produce a 50% likelihood of successful defibrillation (E50) decreased with increasing phase-1 tilt and increased with increasing phase-2 leading-edge voltage except for the 30% phase-1 tilt waveforms. In group 2, 9 waveforms were identical to the waveforms in group 1, except for a 20- microF capacitor for phase 2. E50 decreased with increasing phase-1 tilt. Phase-2 leading-edge voltage of 1.0 to 1.5 V1 appeared to minimize E50 for phase-1 tilt of 50% and 70% but worsened E50 for phase-1 tilt of 30%. There was a significant correlation between E50 and residual membrane voltage at the end of phase 2, as calculated by the charge-burping model in both groups (group 1, R2=0.47, P
ISSN:0009-7322
1524-4539
DOI:10.1161/01.CIR.98.22.2487