Funding for this research was provided by:
British Heart Foundation (FS/16/14/32023)
Marie Curie Research (A15867)
Chief Scientist Office (PCL/18/05)
Received: 20 May 2019
Accepted: 28 February 2020
First Online: 13 March 2020
Ethics approval and consent to participate
: The study was approved by the South East Scotland research ethics committee (reference 12/SS/0223) and all participants provided written informed consent.
: Not applicable.
: The authors declare that they have no competing interests.