Ethics approval and consent to participate
The study was conducted with the approval of the Institutional Review Boards (IRBs) of Ajou University Hospital and Gangnam Severance Hospital, Yonsei University (IRB No. AJIRB-MED-SUR-18–053 & 3–2018-0281). All participants completed written informed consent forms and were assured that their information would remain confidential. Cardiac nurses explained the study’s purpose and the confidentiality of their data to participants, then obtained participants’ voluntary agreements. All methods were carried out in accordance with relevant guidelines and regulations.