SafePAT summarized some important information for patients in the EMR about medical records in a document.
Additionally, there is a lot of information available for patients who seek healthcare across borders in the European Union. Most of this information is offered by the European Committee (see also https://ec.europa.eu/health/cross_border_care/overview_en).
We advise patients to carefully consult experts (like your healthcare professional or the national contact points) when they plan to go across the border for healthcare.