Dad wants me to do a 24 hour test that monitors heart bc of a hereditary artery condition in his family but dont know what it's called, what could be?

A 24 hour monitor: (holter monitor) is unlikely to detect a heart artery condition but may be effective if this is a rhythm disorder he is concerned about. Most hereditary arrhythmia problems are evaluated this way but artery problems are not. Before you obtain an unnecessary test it might be best to check with a health care provider first and determine exactly what is necessary.