Objectives: The objectives were to determine: 1) whether patients with an implantable cardioverter defibrillator (ICD) presenting with anxiety symptoms measured on the Hospital Anxiety and Depression Scale (HADS) have identifiable anxiety according to the Structured Clinical Interview for DSM disorders (SCID) and 2) the type of anxiety, if any, behind a HADS-A score ≥ 8 in patients with an ICD. Methods: Patients with an ICD were screened using HADS and patients with a HADS-A score ≥ 8 were invited to participate. A total of 88 patients were included in the study and were interviewed using the SCID instrument to determine anxiety or adjustment disorder. Results: A total of 56% met the criteria for an anxiety diagnosis, 20% for adjustment disorder with anxiety and 8% for adjustment disorder without anxiety. Frequent types of anxiety were panic disorder, generalized anxiety disorder (GAD) and post-traumatic stress disorder (PTSD). Furthermore, 24 (28%) had an adjustment disorder. Conclusion: A total of 84% meet the criteria for anxiety or adjustment disorder. The most common anxiety diagnoses were panic disorder, GAD and PTSD.