Electronic Health Records (EHRs) are essential to contemporary healthcare but remain limited by fragmented interfaces, poor usability, and inadequate support for complex multimodal data. Mixed Reality (MR) offers new opportunities to address these challenges, yet its integration into clinical information systems is largely unexplored. This paper presents the design and evaluation of a prototype MR-enhanced EHR that enables physicians to visualize and interact with patient data through holographic interfaces. Using MR glasses, clinicians access a three-dimensional representation of the patient’s body augmented with demographics, medical history, and diagnostic data, including 3D-rendered CT and MRI scans. Clinical information is spatially organized and accessed via gaze and gesture, supporting intuitive exploration and collaboration. A two-phase user study assessed requirements, usability, and clinical relevance. Results show strong acceptance among medical students and selective but promising interest among physicians, particularly for imaging, surgical planning, and patient communication. Overall, the findings indicate that MR-based EHRs can reduce cognitive load, improve anatomical understanding, and enhance collaborative and patient-centered care.