Delay is the enemy for patients with acute myocardial infarction. It would be helpful for the hospital cardiologist to interpret the patient's electrocardiogram (ECG) before the arrival of the ambulance. The aim of our study was to determine whether ECG transmission from an ambulance is feasible and to assess the time savings. An ambulance was equipped with an ECG recorder, which was connected to a notebook computer and coupled to a cellular telephone for transmission to a hospital-based station. Paramedics needed 2 min (SD 0.5) to record the ECG on the move and 34 s (SD 14) to transmit it. The ambulance arrived 15.5 min (SD 6.5) after reception. The time between arrival and ECG diagnosis, for a control group patient, was approximately 9.5 min (SD 3.5). Therefore, pre-hospital ECG diagnosis took place 25 min (SD 7.5) before in-hospital diagnosis. We conclude that ECG transmission from a moving ambulance is feasible, reduces in-hospital delays and allows faster triage in critical cardiac cases.