This Master's thesis describes the redesign of the HeartEye portable Electrocardiogram (ECG) device to enable home use for patients with coronary artery disease (CAD). The initiative aimed to transition the medical-grade 12-lead ECG from a clinical setting to a user-friendly, home-based application, maintaining the device’s diagnostic integrity while enhancing accessibility for non-expert users.

The project was done in collaboration with HeartEye, TU Delft, and NPK Design, applying the double diamond design framework that works with four key phases: Discover, Define, Develop, and Deliver.

Discover Phase: The redesign began with an examination of the existing HeartEye ECG device, assessing its design and functionality. Following research explored the opportunities in E-Health, highlighting trends and innovations that could inform HeartEye's integration into telemonitoring service centres. In-depth user group research was conducted to understand the specific needs, behaviours, and experiences of CAD patients, guiding the development of user personas. This phase also looked at the regulatory landscape to ensure that the redesigned device would comply with the most important medical device standards and to address potential future regulations related to AI and sustainability in healthcare. A quick dive into machine learning interpretability was completed. Additionally, market strategies were evaluated to discover if they would have an impact on the to be designed device. Gender-specific issues of heart disease and care were addressed as well. Lastly, a qualitative study enriched by direct patient feedback provided deeper insights into the personal impact of CAD.

Define Phase: Using the knowledge from the Discover phase, a start was made to discover potential use scenarios. A well evaluated choice was made to choose for the rehabilitation to rehabilitation period as the use scenario to be designed for. Once this was defined, we scoped down the design space to only encompass the physical design considerations and set up some boundaries to help make design decisions later on in the project. Lastly, we defined four determinants that determine what makes a good measurement based on expert feedback and research.

Develop Phase: Factors influencing measurement quality were developed, allowing for the exploration of a broad range of directions. Ideas were iteratively conceptualized, prototyped, and refined, with three main directions chosen for further development: housing geometry, feedback methods, and electrode material. These were prototyped and tested in a structured user test, consisting of four parts: quantitative evaluation of device geometries, qualitative interviews about user experiences, a card game to discuss feedback needs and methods, and an internal test on electrode material effects on contact resistance. The results informed design guidelines for the redesign.

Deliver Phase: This phase explored the practical implications of the developed design guidelines, by designing, optimizing, and evaluating a concept design. Moreover, some recommendations are given for the future implementation of the insights generated over the course of this project.

The resulting redesigned HeartEye portable ECG device could empower patients to monitor their cardiac health effectively at home, combining clinical-grade monitoring capabilities with an accessible, user-centric design to potentially reduce CAD-related mortality through timely and frequent monitoring.