This study compared the 5-electrode-derived EASI electrocardiogram (ECG) with the conventional Mason-Likar ECG in 200 consecutive patients with chest pain transported to 3 hospitals by 2 different emergency medical services. No significant differences were observed between the 2 systems for the detection of relevant electrocardiographic abnormalities. A questionnaire administered to participating emergency medical personnel revealed a high degree of acceptability of the EASI ECG, with some participants commenting that the sternal and mid-axillary locations of the EASI electrodes made them easier to apply, especially to women, than conventional precordial electrodes.