Hagihara A, et al. - The interaction between the defibrillation waveform and time to or the number of defibrillation on resuscitation outcomes was examined. Findings revealed an association of an increased number of defibrillations with a decreased return to spontaneous circulation (ROSC) in the case of biphasic and monophasic defibrillation, while an increased number of defibrillations seemed related to an increased 1-month survival rate and cerebral performance category (CPC) (1, 2) only in the case of biphasic defibrillation. When two or more defibrillations were performed, a biphasic waveform compared to a monophasic waveform was more effective in terms of long-term survival.