P4167Non-shockable rhythm related sudden cardiac arrest in the community

Abstract Introduction A significant increase in the prevalence of sudden cardiac arrest (SCA) with non-shockable rhythm has been reported, related to asystole and pulseless electrical activity (PEA). Factors associated with non-shockable rhythm and the mode to the return of spontaneous circulation (ROSC) may help for a better understanding. Purpose We aimed to describe the frequency, characteristics and outcome of SCA related to non-shockable versus shockable rhythm in the community. Methods In this prospective ongoing, multicentre population-based registry (6.7 million inhabitants), data from all SCA over a 5-year period were analyzed. Initial rhythm was obtained from the EMS report and the initial recorded rhythm strip when available. Medical records for each SCA were reviewed by cardiologists to identify underlying aetiology and associated conditions. Results Among the 3,028 SCAs admitted alive out of a total of 18,622 out-of-hospital cardiac arrests from May 2011 to May 2016, 2,904 patients had available information regarding initial rhythm at the time of EMS arrival. Among them, 1,314 patients (45.3%) presented with non-shockable rhythm: 1,109 (38.2%) cases with asystole, 197 (6.8%) with PEA and 8 (0.3%) with high degree atrioventricular block. Cases with non-shockable rhythm were older (60.6 vs. 57.4 years, P<0.001), with greater proportion of females (34.9 vs. 19.2%, P<0.001) and less proportion of family history of coronary artery disease or SCA. Proportion of warning symptoms prior to the SCA was higher among patients with non-shockable rhythm (74.3 vs. 64.9%, P<0.001) but the proportion of chest pain was lower (24.0 vs. 43.3%, P<0.001). Survival rate was much lower in non-shockable rhythm cases (7.2 vs. 42.3%, P<0.001). Among the 1,314 non-shockable cases eventually admitted alive to hospital, 1,022 (77.8%) did not require external defibrillation prior to ROSC, and a majority (91.7%) received adrenaline during resuscitation. In this subgroup, the main identified cardiac cause was acute coronary syndrome (45.3%), followed by chronic CAD (27.1%), structural non-ischemic heart disease (22.4%), and non-structural heart disease (5.2%). Conclusions Initial non-shockable rhythm is encountered in almost half of SCA cases admitted alive; mostly occurs in older patients with higher proportion of females. Over three quarters of these cases did not require external defibrillation prior to ROSC.