Over an 8-year period, despite the increased usage of ICDs, overall nurses had a lack of knowledge in relation to specific key clinical issues on the care of ICD patients. As a consequence, these patients may fail to receive qualified care. Future research should assess knowledge of other health care professionals and focus on interventions that increase and maintain an appropriate knowledge level in care of ICD patients. Relevance to clinical practice The level of nurses' knowledge on care of patients with ICDs needs to be systematically raised in order to ensure appropriate counselling and nursing care.