When seeing a doctor for arrhythmia, if there are things I don't want to discuss in front of family members, can I ask to speak with the doctor alone?

You can ask the medical staff to set aside some time for a private conversation and let them know what information you do not want to share with your companions for the time being. Before your visit, you can write down the issues you need to discuss privately and give them to the doctor. If there are guardianship or other special circumstances involved, please ask the medical institution to explain the scope of confidentiality and the related procedures.