TY - JOUR
T1 - The effects of phase duration on defibrillation success of dual time constant biphasic waveforms
AU - Shan, Yi
AU - Ristagno, Giuseppe
AU - Fuller, Marc
AU - Sun, Shijie
AU - Li, Yongqin
AU - Weil, Max Harry
AU - Russell, James
AU - Tang, Wanchun
PY - 2010/2
Y1 - 2010/2
N2 - Aim of Study: The effects of first and second phase duration of biphasic waveforms on defibrillation success were evaluated in a guinea pig model of ventricular fibrillation (VF). We hypothesized that waveform duration, and especially the first phase duration, played a main role on defibrillation efficacy in comparison to energy, current and voltage, when a dual time constant biphasic shock was employed. Methods: VF was induced and untreated for 5 s in 30 male guinea pigs, prior to attempting a single defibrillatory shock with one of 5 defibrillation waveforms which had different durations of the first and second phase. A five step up-down protocol was utilized for determining the defibrillation efficacy. After a 3-min interval, the procedure was repeated. A total of 25 cardiac arrest events and defibrillations were investigated for each animal. Results: The defibrillation waveforms with an intermediate first phase of 5 ms, yielded the highest defibrillation success (p <0.05). These waveforms also presented significantly lower energy, current and voltage in comparison to waveforms with shorter or longer first phase durations (p <0.001). However, no differences on defibrillation success were observed among waveforms with different second phase durations varying from 1.5 ms to 3.5 ms. Conclusions: For dual time constant biphasic waveforms, the first phase duration played a main role on defibrillation success. The intermediate first phase duration of 5 ms, yielded the best defibrillation efficacy compared with shorter or longer first phase durations. While the second phase duration did not affect defibrillation outcomes.
AB - Aim of Study: The effects of first and second phase duration of biphasic waveforms on defibrillation success were evaluated in a guinea pig model of ventricular fibrillation (VF). We hypothesized that waveform duration, and especially the first phase duration, played a main role on defibrillation efficacy in comparison to energy, current and voltage, when a dual time constant biphasic shock was employed. Methods: VF was induced and untreated for 5 s in 30 male guinea pigs, prior to attempting a single defibrillatory shock with one of 5 defibrillation waveforms which had different durations of the first and second phase. A five step up-down protocol was utilized for determining the defibrillation efficacy. After a 3-min interval, the procedure was repeated. A total of 25 cardiac arrest events and defibrillations were investigated for each animal. Results: The defibrillation waveforms with an intermediate first phase of 5 ms, yielded the highest defibrillation success (p <0.05). These waveforms also presented significantly lower energy, current and voltage in comparison to waveforms with shorter or longer first phase durations (p <0.001). However, no differences on defibrillation success were observed among waveforms with different second phase durations varying from 1.5 ms to 3.5 ms. Conclusions: For dual time constant biphasic waveforms, the first phase duration played a main role on defibrillation success. The intermediate first phase duration of 5 ms, yielded the best defibrillation efficacy compared with shorter or longer first phase durations. While the second phase duration did not affect defibrillation outcomes.
KW - Defibrillation efficacy
KW - Dual time constant defibrillation waveform
KW - Ventricular fibrillation
KW - Waveform duration
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U2 - 10.1016/j.resuscitation.2009.10.022
DO - 10.1016/j.resuscitation.2009.10.022
M3 - Article
C2 - 19945206
AN - SCOPUS:74249088085
VL - 81
SP - 236
EP - 241
JO - Resuscitation
JF - Resuscitation
SN - 0300-9572
IS - 2
ER -