Four in ten paramedic-suspected STEMIs had another final diagnosis

Design

Retrospective statewide ambulance registry cohort

Population

7,205 paramedic-suspected STEMI attendances with a discharge diagnosis

Primary outcome

Final diagnosis and mortality

Effect

STEMI confirmed in 60.1%; non-cardiac diagnosis mortality HR 1.75 (95% CI 1.47–2.09) vs STEMI

A statewide ambulance registry in Victoria, Australia, followed 8,077 paramedic-suspected STEMI attendances from 2020 to 2025; 7,205 had a recorded discharge diagnosis.

STEMI was confirmed in 60.1%. The rest had non-ST-elevation or other coronary syndromes (11.4%), other cardiac diagnoses (10.5%), non-cardiac diagnoses (8.5%) or symptom-only diagnoses (9.4%). In-hospital mortality across the whole group was 8.6%. Over a median 2.8 years, those with a non-cardiac final diagnosis had higher adjusted mortality than confirmed STEMI (HR 1.75, 95% CI 1.47–2.09); the other groups did about as badly as STEMI.

The pre-hospital STEMI pathway is meant to be sensitive, and some over-calling is the price of speed. The useful point for the emergency physician is that a patient arriving on the STEMI pathway who turns out not to have STEMI is not a low-risk patient — they often have a serious alternative diagnosis that needs as much attention.

• Keep reperfusion access fast — most suspected STEMIs were real
• Reassess every pathway patient on arrival for alternative diagnoses such as dissection, sepsis or PE
• Do not de-escalate care because STEMI was not confirmed; these patients had high mortality
• Treat the non-cardiac group as particularly high risk

Why it matters

The 'not a STEMI' patient can slip down the priority list just when they need it most.

Don't overread it

This describes one pathway population; it does not apply to all chest pain or all confirmed STEMI.

The statistics, in plain English

A hazard ratio of 1.75 means those with a non-cardiac final diagnosis died at about three-quarters more the rate of confirmed STEMI patients over follow-up, after adjustment for available factors.

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