Background <p>Anxiety related to cardiac catheterization (ARCC) is highly prevalent and most severe in the immediate preoperative period. ARCC is associated with increased myocardial oxygen consumption, blood pressure variability, and increased risk of arrhythmias, leading to higher rates of intraoperative complications and worse physical, emotional, and cognitive functioning.</p> Objective <p>To describe a nurse-led complex intervention (CI) designed to reduce ARCC in adults before a cardiac catheterization (CC).</p> Methods <p>To design the intervention, a concept analysis yielded the identification of ARCC antecedents and attributes, based on which CI components and objectives were determined. For each component, CI procedures, mode of delivery, and dose were established based on empirical evidence. The CI was reported according to the Template for Intervention Description and Replication checklist.</p> Results <p>The Education and Music Intervention to Reduce Anxiety (EMIRA) consists of two components. The educational component provides the essential information regarding CC purpose, catheterization laboratory features, and what to expect before, during, and after the procedure. The musical component provides individuals with a feeling of comfort and relaxation. EMIRA is delivered in one 30-min session using an audiovisual format. EMIRA’s expected primary outcome is a decreased state anxiety level. Additionally, EMIRA might reduce blood pressure, heart and respiratory rates, and chest pain.</p> Conclusions <p>EMIRA is a CI developed with methodological rigor. Future studies should evaluate the acceptability, feasibility, and efficacy of EMIRA.</p>