The PREDICT calibration study is a prospective, non-interventional trial aiming to adapt and calibrate the ACS-Pathfinder algorithm for prehospital triage of patients with suspected non-ST-elevation acute coronary syndrome (NSTE-ACS) in Germany. Approximately 304 patients will be enrolled by six emergency medical service (EMS) stations. All patients will receive standard care and an additional point-of-care troponin test (POCT) performed in the ambulance. Clinical and biomarker data will be collected using a study app, without influencing patient management. Follow-up will be conducted up to 90 days through telephone interviews and hospital record review.

The primary objective is to determine the true prevalence of myocardial infarction and calibrate the ACS-Pathfinder algorithm accordingly. Secondary objectives include assessing feasibility, workflow, acceptance, and data processes within the EMS as preparation for a subsequent cluster-randomized main study.

The study is coordinated by Prof. Holger Thiele (Heart Center Leipzig) with co-investigators from Leipzig and Hamburg. The sponsor is Leipzig Heart Science gGmbH. Study duration is planned from January to November 2026.

Inclusion Criteria:

• Suspected myocardial infarction
• Symptom onset >30 minutes before arrival of emergency medical services
• Written informed consent

Exclusion Criteria:

• STEMI on initial ECG
• Unstable angina, hemodynamic instability, life-threatening arrhythmias, cardiac arrest
• Non-ischemic causes requiring hospitalization
• Emergency physician dispatch at the request of a primary care physician
• Age <18 years

The study population includes adult patients with suspected myocardial infarction who are attended by emergency medical services (EMS). Eligible participants must have symptom onset more than 30 minutes before EMS arrival and be able to provide written informed consent.

Patients will be excluded if they present with ST-elevation myocardial infarction (STEMI) on the initial ECG, unstable angina, hemodynamic instability, life-threatening arrhythmias, or cardiac arrest. Additional exclusion criteria include non-ischemic conditions requiring hospital admission, EMS deployment requested by a primary care physician, and age under 18 years.