Funding for this research was provided by:
British Heart Foundation (CH/16/2/32089 and RG/16/1/32092)
Received: 1 December 2017
Accepted: 23 May 2018
First Online: 9 July 2018
Ethics approval and consent to participate
: The study was performed in accordance with the Declaration of Helsinki (October 2000), with all volunteers providing informed written consent. Ethical approval was given by NRES Committee Yorkshire and the Humber – Leeds West, Ref 12/YH/0551.
: The authors declare that they have no competing interests.
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