Characteristics and outcomes of patients presenting with out of hospital cardiac arrest to a regional hospital

Abstract

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Out of hospital cardiac arrest (OHCA) carries a high rate of mortality and can be due to cardiac or non-cardiac causes. We reviewed consecutive patients presenting with OHCA to the emergency department of a regional hospital in Australia, between January 2019 and March 2022. Medical records were reviewed to assess presenting rhythm, final diagnosis, risk factors known at time of presentation, results of cardiac investigations and survival to hospital discharge. Results Over the study period, 107 patients presented with cardiac arrest, with an average age of 67 years (range 29 to 95 years). Most patients were male (70, 67%), although in those with a non-cardiac cause identified only 53% were male. An underlying cardiac cause was identified in 50 (47%), a non-cardiac cause was identified in 18 (17%), and 39 (36%) had no identifiable cause. The most common cardiac causes were ST-elevation myocardial infarction (18, 36%), followed by non-ischaemic cardiomyopathy (9, 18%) and scar-related arrhythmia (7, 14%). Overall, ischaemic heart disease was responsible for 31 (62%) cases. Coronary angiography was performed in 36 (72%) of cardiac cases. Those who were diagnosed with ST-elevation myocardial infarction had an average time from presentation to coronary angiography of 61 minutes while the average was 38 hours for all patients presenting with OHCA. The most common presenting rhythm was ventricular fibrillation (39, 38%). The overall mortality rate was 61% for all OHCA. Among those with a cardiac cause, a non-cardiac cause or no cause identified for the OHCA, the mortality rates were 32%, 87% and 87% respectively. Data published by the regional Ambulance Service show that the survival to discharge from hospital of 39% in our regional hospital is comparable with state-wide outcomes. Discussion These data reflect the significant mortality and wide spectrum of disease underlying OHCA, and thus the challenge of managing patients presenting with OHCA. Cardiac disease accounts for almost half of all cases of OHCA, and also encompasses a wide spectrum of disease. However, the mortality in patients with OHCA due to an underlying cardiac cause, while still significant, is better than those patients in whom no cardiac cause is identified.