MARS E-ECG: Prehospital Electrocardiogram Teletransmission by Firefighter Rescuers: A Retrospective Pilot Study within a Physician-Based EMS System

Introduction: Prehospital electrocardiogram teletransmission (E-ECG) enables early cardiac diagnosis and triage in the field. This study assessed its diagnostic and operational impact in a real-world Emergency Medical Service (EMS) in Marseille, France. Methods: A retrospective, single-center observational study including adults ≥18 years who underwent E-ECG acquisition by Marseille first responders from January 1 through September 15, 2023 was conducted. Electronically transmitted prehospital ECGs were transmitted via Schiller devices to medical regulators. Patients with trauma, pediatric age, pregnancy, training cases, uninterpretable ECGs, or incomplete files were excluded. The main outcome was the proportion of acute ECG abnormalities (signs of ischemia, rhythm, or conduction disorders). Secondary outcomes included reinforcement requests, patient orientation, and transport mode. Results: Among 425 included patients (Median age: 56 years [IQR 40–72]; 61% male), 21.9 % (n = 93) presented abnormal ECGs, including 2.1% with ST-elevation myocardial infarction (STEMI). Transmission results led to management changes in 11.5% of cases (n = 49): 8.2% required additional medical reinforcement and 3.3% underwent direct cardiology triage without medical reinforcement. Technical issues occurred in 15.8% of transmissions (n = 67). Conclusion: Prehospital ECG teletransmission allowed early detection of cardiac abnormalities and was associated with changes in patient management in a subset of cases. Its integration in emergency workflows could enhance triage, optimize cardiology routing, and strengthen coordination between field teams and regulation centers.