The position, previously known as director of policy and comms, has been split in two, with Davidge handling comms and Mike Hobday to looking after policy.
The pair step in to replace Betty McBride, who was director of policy and comms but retired in May.
Davidge, who was comms director at Cancer Research UK, will be heading up the approximately 50-strong marketing and engagement team at the cardiovascular research charity.
She will join the BHF in October, taking over from interim director, Nick Radmore.
She said: "The charity is well-known, highly respected and has a track record of producing memorable and impactful communications. I’m looking forward to building on those strengths to support the charity’s ambitious plans for the future."
There were also two more director-level appointments; Hobday will become director of policy and Catherine Kelly will be director of prevention, survival and support.
All three will report directly to CEO Simon Gillespie, who said: "Carolan, Mike and Catherine will play vital roles in leading our dedicated team of staff and volunteers to win the fight against a disease that damages the lives of far too many people."
The appointments come as the charity gets set to launch its new strategy 'We fight for every heartbeat: our strategy to 2020' next month.