ZOLL X Series Monitor Defibrillator Rev H - Manual (Page 311)

Clinical Trial Results for the Biphasic Waveform
9650-001355-01 Rev. H X Series Operator’s Guide A-25
Clinical Trial Results for the Biphasic Waveform
The efficacy of the ZOLL Rectilinear Biphasic waveform has been clinically verified during a
study of defibrillation of Ventricular Fibrillation (VF) and Ventricular Tachycardia (VT). A
feasibility study was performed initially for defibrillation of VF/VT (n=20) on two separate
groups of patients to ensure waveform safety and energy selection. Subsequently, a separate,
multicenter, randomized clinical trial was performed to verify the waveform’s efficacy. A
description of this study is provided below. The study was performed using ZOLL defibrillation
systems consisting of ZOLL defibrillators, the ZOLL Rectilinear Biphasic waveform, and
ZOLL defibrillation electrodes.
Randomized Multicenter Clinical Trial for Defibrillation of
Ventricular Fibrillation (VF) and Ventricular Tachycardia (VT)
Overview: The defibrillation efficacy of the ZOLL Rectilinear Biphasic waveform was
compared to a monophasic damped sine waveform in a prospective, randomized, multicenter
study of patients undergoing ventricular defibrillation for VF/VT during electrophysiological
studies, ICD implants, and test. A total of 194 patients were enrolled in the study. Ten patients
who did not satisfy all protocol criteria were excluded from the analysis, leaving a study
population of 184.
Objectives: The primary goal of this study was to compare the first shock efficacy of the 120 J
rectilinear biphasic waveform with a 200 J monophasic waveform. The secondary goal was to
compare all shock (three consecutive 120, 150, and 170 joules) efficacy of the rectilinear
biphasic waveform with that of a monophasic waveform (three consecutive 200, 300, and
360 joules). A significance level of p=0.05 or less was considered statistically significant using
Fischer’s Exact test. Also, differences between the two waveforms were considered statistically
significant when the customary 95% or AHA-recommended 90%
1
confidence interval between
the two waveforms was greater than 0%.
Results: The study population of 184 patients had a mean age of 63±14 years. Of these,
143 patients were male. 98 patients were in the biphasic group (ventricular fibrillation/flutter,
n=80; ventricular tachycardia, n=18) and 86 patients were in the monophasic group (ventricular
fibrillation/flutter, n=76; ventricular tachycardia, n=10). There were no adverse events or
injuries related to the study.
The first shock, first induction efficacy of biphasic shocks at 120 J was 99% versus 93% for
monophasic shocks at 200 J (p=0.0517, 95% confidence interval of the difference of –2.7% to
16.5% and 90% confidence interval of the difference of –1.01% to 15.3%).
1.Kerber RE, et al., “Automated External Defibrillators for Public Access Defibrillation: Recommendations for Specifying and Reporting
Arrhythmia Analysis Algorithm Performance, Incorporating New Waveforms, and Enhancing Safety,” Circ J Am Heart Assoc.
1997;95:1677-1682.
“… the task force suggests that to demonstrate superiority of an alternative waveform over standard waveforms, the upper boundary
of the 90% confidence interval of the difference between standard and alternative waveforms must be <0% (ie, alternative is
greater than standard).”
Monophasic Biphasic
First shock efficacy 93% 99%
p-value 0.0517
95% confidence interval –2.7% to 16.5%
90% confidence interval –1.01% to 15.3%