Approximately half a million people in Canada suffer from heart failure (HF), a leading cause of hospital admission. HF outcomes can be improved by self-care behaviors, to which patients often show low adherence. This study focuses on the co-design of an online self-care application and community intervention, called HFApp, which patients with HF and their informal caregivers could use to potentially improve HF outcomes. The intended users for HFApp are older adults with HF and their informal caregivers. The primary objective of this study is to identify themes for the development of HFApp. The secondary objective is to apply these findings to identify user needs and preferences for HFApp. Persona-scenario discussion sessions were conducted with 4 older patients with HF (≥ 60 years) and 4 informal caregivers from the Hamilton Health Sciences Heart Function Clinic. One persona-scenario discussion session was held for each participant type (i.e. patients with HF or informal caregivers). Participants were divided into pairs and participant pairs created personas and scenarios together. Scenarios included: (1) how they learn about HFApp, (2) how they might access HFApp, (3) where they are when they use HFApp, (4) who might help them with HFApp, and (5) how often they use HFApp. All discussions were audio recorded. Data analysis, using NVivo 10 , provided six categories of design themes which were used to develop a list of user requirements for HFApp. Some of these requirements help users perceive HFApp to be more useful and give a sense of self-care confidence. However, some requirements may be excluded due to low feasibility. It is recommended that a larger persona-scenario group session be conducted in the future to support the requirements gathered in this study as well as identify any new requirements. / Thesis / Master of Science (MSc) / Approximately half a million Canadians suffer from heart failure (HF), a leading cause of hospitalization. This study focuses on the involvement of potential users in the design of HFApp, an online HF self-care application (“app”). These users include older patients with HF and their family and close friends. One of HFApp’s objectives is to potentially decrease hospital visits for older patients with HF. A design based on patient preferences called persona-scenarios was used to conduct this study. Participants were asked to create pretend individuals that were similar to themselves and describe scenarios in which these individuals would interact with HFApp. These could include: (1) how they learn about HFApp, (2) how they might access HFApp, (3) where they are when using HFApp, (4) who might help them with HFApp, and (5) how often they use HFApp. These interactions will be used to identify user requirements and preferences for HFApp’s design.