Prehospital 12-lead ECG and outcomes in acute coronary syndrome

Importance/background: The 12-lead ECG is recommended in clinical guidelines for prehospital assessment of patients with suspected acute coronary syndrome (ACS) presenting to Emergency Medical Services (EMS).

Objectives: To determine prehospital ECG (PHECG) utilisation since UK national rollout of primary percutaneous coronary intervention, and whether this is associated with clinical outcomes in patients with ACS.

Design: Population-based, linked cohort study using Myocardial Ischaemia National Audit Project data from 1 January 2010 to 31 December 2017, related to patients with ACS conveyed by the EMS to hospital in England and Wales.

Exposure: PHECG administration.

Outcomes: Proportion of patients where PHECG was recorded, 30-day and 1 year all-cause mortality, use of reperfusion.

Results: Of 330 713 eligible patients transferred by EMS, 263 420 patients (79.7%) had PHECG recorded, steadily increasing from 74.2% in 2010 to 85.0% in 2017. Patients who received PHECG were generally younger than those who did not (median age: 70 years vs 75 years), less likely to be female (32.8% vs 41.9%) or to have comorbidities such as diabetes (20.8% vs 24.7%) or peripheral vascular disease (4.1% vs 4.8%). Patients who received PHECG had lower mortality at 30 days (7.1% vs 10.9%), with adjusted OR 0.77 (95% CI 0.75 to 0.80), and at 1 year (14.2% vs 23.2%), with adjusted OR 0.69 (95% CI 0.68 to 0.71). Adjustment accommodated demographic characteristics, comorbidities and medical history. Reperfusion was more frequent in patients with ST-elevation myocardial infarction (STEMI) receiving PHECG (84.5% vs 54.7%) with adjusted OR 4.37 (95% CI 4.20 to 4.54), with similar adjustment.

Conclusions: Use of PHECG by EMS for patients with ACS is associated with lower short-term mortality and higher odds of receiving reperfusion for STEMI patients. Administration of PHECG increased steadily over time, but at the end of the study, still 15% of eligible patients did not receive a PHECG.