Each instructor must complete an online transition class for each discipline they hold a certificate for. BLS Instructors need to complete the transition course for BOTH BLS and Heartsaver even if you never teach HeartSaver classes.
As an example: An instructor who has an ACLS Instructor and BLS Instructor certificate would need to complete 3 transition classes. (ACLS, BLS, and Heartsaver).
If you are a BLS Instructor and do not teach ANY heartsaver classes, you do not need to purchase Heartsaver materials but you still need to complete the online transition training.