Temporal trends in incidence, characteristics and survival outcomes for asystolic out-of-hospital cardiac arrest.

Abstract

Aim: To describe temporal trends in the incidence, characteristics and outcomes of out-of-hospital cardiac arrest (OHCA) from initial asystole. Method(s): We included all OHCA patients aged >=16 years with an initial asystolic arrest rhythm in Victoria, Australia, occurring during 2003-2022. Patients witnessed to arrest by emergency medical services (EMS) personnel were excluded. Multivariable logistic regression was used to examine trends in survival. Result(s): A total of 75,262 asystolic OHCA met the eligibility criteria, of which 19,517 (25.9%) received an attempted resuscitation (EMS-treated). The age-standardised incidence of EMS-attended cases did not change significantly over time (84.1 cases per 100,000 population in 2003 versus 77.8 in 2022, p for trend = 0.201). Among EMS-treated cases, arrests in aged care facilities, traumatic aetiology and arrests in rural regions, all increased over the study period (p for trend < 0.05). Although bystander cardiopulmonary resuscitation rates increased substantially (37.1-71.1%, p for trend < 0.001), bystander-witnessed arrests declined (42.8-35.2%, p for trend < 0.001). Survival to hospital discharge decreased from 1.2% to 0.3% (p for trend < 0.001) and prehospital ROSC decreased from 17.8% to 15.4% (p for trend < 0.001). Among 12-month survivors completing telephone follow up (n = 42 of 55 eligible), the rate of favourable functional outcome (Glasgow Outcome Scale Extended >=5) was 54.8%. After adjustment, the period 2018-22 was associated with lower odds of survival to hospital discharge compared to 2003-07 (adjusted odds ratio = 0.42, 95% Confidence Interval: 0.23-0.75, p = 0.004). Conclusion(s): Survival and long-term outcomes for initial asystolic OHCA remain persistently poor despite increased bystander CPR and system-level improvements.Copyright © 2026 The Authors