No major assessment technology for emergency department (ED) patients is used more often than the ECG. Although the ECG is an old diagnostic method, except for a few specific conditions (eg myocardial infarction) the clinical value of different ECG findings has been remarkably little studied in ED patients. In this project, we exploit the large transnational EXPECT (Evaluation of Unknown Predictors of Electrocardiographic Changes – a Transnational study) database to study the clinical value of ECG in different ED patients. With the use of ECGs and clinical data from at least 200,000 ED patient visits from Lund and Helsingborg in Sweden and Odense and Esbjerg in Denmark, we will evaluate the diagnostic and prognostic value of a range of ECG findings in different medical conditions. With the size and quality of the EXPECT database, the goal is to provide results and conclusions more reliable than in any previous studies.