Bartling, now MD for the practice, was previously deputy MD. She transferred to London from Edelman’s Chicago office as a director for the health team in 2010.
Gittins joined Edelman in September after six years at The Red Consultancy and left in November.
Currently a consultant, he told PRWeek: "I just realised quite quickly that this wasn’t the place for me."
Bartling said: "When I joined Edelman more than a decade ago, I was immediately won over by the culture of the organisation and the passion and creativity of the team. I have now experienced Edelman on both sides of the Atlantic and remain energised by the challenges posed by the healthcare marketplace and the opportunities our clients bring.
"I welcome the chance to lead and nurture our smart and talented Edelman London Health team as we continue to find new ways to advance our clients’ brands."