BACKGROUND: Clinical practice guidelines for acute coronary syndrome recommend an interval between electrocardiogram (ECG) and balloon of <
60 min in patients attending the emergency department (ED) of a hospital with primary angioplasty capacity. Compliance with this can be complex, especially in atypical presentations. OBJECTIVE: To assess the effectiveness of specific training for ED triage nurses in reducing ECG-balloon time in STEMI. METHODS: Quasi-experimental study with a pre-test-post-test design. In June 2021, a training intervention was implemented in the diagnosis of STEMI in the ED. The EDUCAMI program included complex presentations, emphasising disparities in women and elderly people. A historical sample was compared with a post-intervention sample. All patients consecutively activated as code STEMI in the ED were included, excluding those activated out-of-hospital. The main variable was ECG-balloon time, which was compared according to sex and age. RESULTS: The final sample consisted of 447 patients distributed into historical sample (n = 327) and post-test groups (n = 120). A reduction from 88 (65-133) to 60 (50-116) minutes in ECG-balloon time was observed in the post-test group together with a shorter hospital stay of 5 (3-8) vs 4 (3-5.5) days (p= 0.013). When comparing according to sex and age, a decrease in ECG-balloon time (p <
0.001) was observed in men and patients under 65 years of age (p <
0.001). CONCLUSIONS: The training intervention proved effective, reducing the ECG-balloon time by 32 %. EDUCAMI reduces the time in men and young people, however, the bias persists in women and those over 65 years of age.