A rheumatic heart disease patient received a call from an unknown number asking for payment for a follow-up visit. How can they verify whether this was arranged by the hospital?

First, independently contact the hospital using the contact information on the hospital's official website, previous visit records, or a legitimate appointment platform. Confirm whether there is a corresponding follow-up arrangement, the responsible department, and the official payment channel. Before verification, do not provide verification codes, complete medical records, or payment information to unknown contacts. Whether the follow-up is necessary should be confirmed with the team actually responsible for diagnosis and treatment.