Resuscitation
-
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. ⋯ 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.