Design: Retrospective statewide registry cohort
Population: 7,205 paramedic-suspected STEMI patients with a recorded discharge diagnosis
Primary outcome: Final diagnosis and mortality during follow-up
Effect: STEMI confirmed in 60.1%; non-cardiac diagnosis HR 1.75 (1.47–2.09) vs STEMI

A statewide registry study in Annals of Emergency Medicine (6 October) followed 7,205 patients in Victoria, Australia, whom paramedics had flagged as suspected STEMI between 2020 and 2025, with recorded hospital diagnoses.

STEMI was confirmed in 60%. A further 11% had other acute coronary syndromes, 11% other cardiac diagnoses, 9% non-cardiac diagnoses and 9% symptom-only diagnoses. Over a median of 2.8 years, patients with non-cardiac diagnoses had higher adjusted mortality than those with confirmed STEMI (hazard ratio 1.75).

Pre-hospital activation is meant to be sensitive, so false positives are expected. The point for emergency teams is that the 40% without STEMI are not low-risk: aortic dissection, pulmonary embolism, sepsis and other serious conditions hide among them.

About 40% of paramedic-activated STEMI calls were not STEMI
Non-cardiac final diagnoses carried higher long-term mortality than STEMI
Keep dissection, pulmonary embolism and sepsis in mind when the cath lab is stood down
Do not slow reperfusion pathways; refine the diagnosis in parallel

Why it matters

Patients stood down from the STEMI pathway are a high-risk group, not a reassuring one.

The statistics, in plain English

HR 1.75 (95% CI 1.47 to 2.09) means patients with a non-cardiac diagnosis died at a faster rate over follow-up than those with STEMI, after adjusting for measured differences.