Is arrival by ambulance a risk factor for myocardial infarction in emergency department patients with cardiac sounding chest pain?

Patients commonly present to the ED with cardiac sounding chest pain1 and a non-diagnostic ECG, yet an important proportion will be suffering from a myocardial infarction (MI) eligible for percutaneous coronary intervention.2 Age, male sex, hypertension, diabetes mellitus, hyperlipidaemia, ischaemic heart disease and smoking are all associated with an increased likelihood of an MI,2 but another potential predictor may be mode of ED arrival. Previous research from the USA found no association between ED arrival by ambulance and MI in patients with chest pain.3 In that study, 26% of patients with chest pain arrived by ambulance, but in the UK ambulances are freely accessible and often used to convey patients with chest pain to hospital.4 We determined whether ED arrival by ambulance was associated with the development of type 1 (acute atherosclerotic plaque rupture and thrombosis) or type 4b (in-stent thrombosis) or type 4c (in-stent restenosis) MI or cardiac death in a UK population.

A retrospective analysis of adult (≥16 years) patients presenting to the ED of Aberdeen Royal Infirmary with chest pain suspicious for an MI and a non-diagnostic ECG was performed. Aberdeen Royal Infirmary is a tertiary referral hospital with approximately 60 000 adult ED attendances annually, and 36% of all patients arrived by ambulance in 2023. The study population comprised two cohorts: a …