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Aim of the Study: Prognosis in out-of-hospital cardiac arrest (OHCA) depends on cardiopulmonary resuscitation (CPR) duration. Therefore, the optimal biphasic defibrillation waveform shows high conversion rates besides low energy. Matthew Fishler theoretically predicted it to be truncated ascending exponential. We realised a prototypic defibrillator and compared ascending with conventional rectangular waveforms in modelled OHCA and CPR., Methods: Approved by the authorities, 57 healthy swine (Landrace ​× ​Piétrain) were randomised to ASCDefib ( n 26) or CONVDefib ( n 26). Five swine served as sham control. We induced ventricular fibrillation (VF) electrically in anaesthetised swine randomised to ASCDefib or CONVDefib and discontinued mechanical ventilation. After 5 ​min of untreated cardiac arrest, we started CPR with mechanical chest compressions and ventilation. We performed transthoracic biphasic defibrillations after 2, 4, 6 and 8 ​min CPR targeting 4 ​J/kg in either group. Depending on the randomised group, the defibrillation protocol was either three ascending followed by one rectangular waveform (ASCDefib) or three rectangular followed by one ascending waveform (CONVDefib)., Results: Under our model-specific conditions, VF was initially terminated by 13/80 ascending waveforms and 13/79 rectangular waveforms and persistent return of spontaneous circulation was achieved in 8/26 (ASCDefib) vs. 10/26 (CONVDefib) animals. Mean current rather than waveform design was predictive for defibrillation success in a generalised linear model., Conclusion: Contrary to theoretical assumptions, transthoracic biphasic defibrillation with ascending waveforms is not superior to rectangular waveforms in modelled OHCA. We advocate defibrillation dosage to be guided by current, that has proven its predictive value again., Institutional Protocol Number: 84-02.04.2017.A176., Competing Interests: T. Annecke reports research funding from Aerogen, B. Braun Foundation, CIO Koeln Bonn, CytoSorbents Europe, Medtronic and PULSION Medical Systems; outside the submitted work. Prof Steven reports research grants from Abbott, Boston and Medtronic, outside the submitted work; honoraria from Abbott and Boston Scientific, outside the submitted work. The remaining authors have disclosed that they do not have any conflicts of interest., (© 2020 The Author(s).)

Rats were injected with oil on Days 17.5 and 18.5 of pregnancy or with 2 mg of testosterone propionate (TP) on Days 15.5 and 16.5, or Days 17.5 and 18.5, or Days 19.5 and 20.5. The female offspring were given oil or 5 micrograms of TP on Day 25 postconception. Among females exposed to TP only during prenatal ontogeny, a lower proportion of those treated on Days 17.5-18.5 of gestation displayed lordotic behavior than did the control group. Postnatal TP alone did not affect lordosis. However, all groups receiving combined pre- and postnatal TP showed impaired estrous patterns. The development of several components of morphology also was differentially affected by the timing of the androgen exposure. The data suggest that the differentiation of sexual behavior and reproductive morphology in the rat are influenced by an interaction of androgen dependent processes operating at different stages of perinatal ontogeny. Further, there may be an optimal fetal period during which androgenization sensitizes animals to low levels of testosterone circulating during neonatal development.