Abstract Body: Background: Observational studies suggest that heart attack mass media campaigns may help prevent out-of-hospital cardiac arrest (OHCA).
Aim: This study evaluated the effectiveness of a community heart attack education intervention (Heart Matters) in high-risk regions of Victoria, Australia—characterised by elevated cardiovascular risk, high OHCA rates, and low ambulance use for ACS—on the secondary outcomes of OHCA incidence and survival.
Intervention: A stepped-wedge cluster randomized trial was conducted in eight high-risk communities (Dec 2021–Mar 2023), with clusters transitioning every four months; a parallel program evaluation was also conducted. The intervention included a heart attack education program delivered by Coordinators directly to the community (n= 10,088 on 490 occasions), household mailouts (n=174,110 households), opportunistic media, and geo-targeted social media. Secondary outcomes of OHCA incidence and survival were evaluated in adult OHCAs of presumed cardiac etiology attended by emergency medical services (EMS) as reported in the Victorian Cardiac Arrest Registry.
Results: There were 977 adult OHCAs of presumed cardiac etiology in the intervention communities (485 control period and 492 intervention period). Median age 70 years (IQR: 57 to 81), 65% were male, 65% unwitnessed, 40% received bystander CPR and 16% had an initial shockable rhythm. The intervention did not reduce OHCA incidence rates (control: 1.5 per 10000 community residents vs. intervention: 1.9 per 10000; incidence rate ratio = 1.39 (95%CI: 0.80, 2.81) or OHCA survival overall (6.8% vs 5.9%, risk difference 0.84 (-4.69, 6.38). The study regions were impacted by a major flooding event in October 2022. Coordinators reported responding to public concerns about media reports of EMS and Emergency Department demand and wait times throughout the intervention.
Conclusion: The Heart Matters heart attack education program intervention that was delivered to communities with elevated cardiovascular risk within Victoria, Australia, did not improve OHCA incidence or survival rates. Alternate education methods may be required to influence change.