Background Heart failure (HF) continues to show an increasing prevalence and despite NICE guidance recommending that all patients with heart failure should receive cardiac rehabilitation (CR) participation in CR remains poor.

Aim To provide an additional mode of access to CR by digitally adapting, the evidence-based REACH-HF intervention, a facilitated home-based programme that clinically effective and cost-effective.

Methods We took an iterative approach to intervention development, exploring patient, caregiver, and healthcare professional (N=19) perceptions of various iterations of prototype designs of the D:REACH-HF platform with up to 2 interviews per participant resulting in 24 think aloud interviews (n= 28). Interviews were thematically coded and data were organised in a Table of Changes to help inform next design iteration. A patient advisory group was involved in interpreting findings and providing input into changes to designs.

Results The think aloud interviews focused on design, navigational, functional and content. Participants talked about barriers to navigation where links or buttons were not present, or clearly visible. Other barriers to accessibility were of font sizes, colour scheme, and ambiguous use of icons. Design issues were often accompanied by mentions of potential. For example, the ability to change text size, image contrast, as well as more complex functionality like sharing self-monitoring tools (progress trackers) with family and friends and setting medication reminders. Although, presentation of the content required breaking up in smaller chunks to be less overwhelming in places, persuasiveness of the content was less often highlighted as requiring change.

Conclusion Following the think aloud interviews (having worked with the intended users of the intervention and ensure that users’ perspectives are taken into account) we shared these with our industry partner (Health and Care Innovations) and we now have a fully functional digital version of REACH-HF which is being test for acceptability and feasibility.