Assessment of the Technical Interpretability of Prehospital ECGs Performed by Medical and Nonmedical Teams in a French Emergency Medical System: A Descriptive Pilot Study.

Abstract

Background: In prehospital emergency care systems, early electrocardiogram (ECG) acquisition is essential for patient triage and management. In France, nonmedical personnel, such as private ambulance technicians and firefighters, were authorized to perform ECGs. While ECGs are crucial for diagnosis, the technical quality and interpretability of these ECGs when transmitted to emergency medical dispatch centers remain uncertain, especially with newly trained nonmedical personnel for emergency medical services (EMS) (private ambulance drivers and public firefighters). This study aimed to assess the technical interpretability of prehospital ECGs transmitted to the emergency dispatch center, according to the type of prehospital team performing ECG acquisition.

Methods: A retrospective observational study was conducted at Angers Emergency Medical Dispatch Centers, France. Adult patients who underwent prehospital ECG acquisition by either mobile intensive care units (MICUs) or nonmedical EMS teams were included. The primary endpoint was the technical interpretability of ECGs based on predefined core technical criteria derived from guideline-based ECG acquisition standards, including patient identification, recording speed and calibration, baseline stability, and absence of interference by the MICUs or nonmedical team. Precordial R-wave transition was analyzed separately as an exploratory marker of potential electrode placement issues. To assess this outcome, all ECGs were analyzed by two independent emergency physicians blinded to clinical data and team type, with consensus adjudication in case of disagreement.

Results: A total of 149 prehospital ECGs were analyzed, including 125 performed by MICU teams and 24 by nonmedical EMS. In a sensitivity analysis excluding ECGs with ST-elevation myocardial infarction or conduction abnormalities and removing the R-wave transition criterion from the endpoint, overall interpretability increased to 73.7% (95% CI: 65.1%-80.8%, n = 87/118). No statistically significant difference was observed between MICU teams (73.7%; 95% CI: 64.3%-81.4%, n = 73/99) and nonmedical EMS (73.7%; 95% CI: 51.2%-88.2%, n = 14/19) (RR 1.00; 95% CI: 0.75-1.34; p = 1). Normal R-wave progression was frequently observed (53%) and was analyzed as an exploratory finding.

Conclusion: In this prehospital setting, less than half of ECGs met predefined composite technical interpretability criteria. However, these criteria reflect a strict technical assessment and should not be directly equated with clinical usefulness. No significant difference was observed between medical and nonmedical teams, although the study was underpowered and estimates were imprecise. These findings highlight the technical challenges of ECG acquisition in prehospital emergency care and support the need for prospective studies to optimize training, standardization, and quality assurance. Larger prospective studies with balanced group sizes are needed to evaluate the clinical impact of prehospital ECG acquisition by nonmedical personnel and to formally assess comparative performance.