Oving I, de Graaf C, Karlsson L, et al. - Considering a previous research suggesting a decline in the proportion of a shockable initial rhythm in out-of-hospital cardiac arrest (OHCA) during the last decades, researchers here sought to determine if this decline is still ongoing. Further they investigated the correlation between location of OHCA (residential vs public) and proportion of a shockable initial rhythm as initial rhythm. They used pooled data from the COSTA-group (Copenhagen, Oslo, Stockholm, Amsterdam) to calculate the proportion of patients with a shockable initial rhythm between 2006–2015. Inclusion of a total of 19,054 OHCA cases was done. Observations revealed a reduction in the total proportion of cases with a shockable initial rhythm in OHCAs at a residential location. During the second half of the study period (2011–2015), this decline remained stable. No decline in shockable initial rhythm was observed over time in public locations.