Remote photoplethysmography for cardiorespiratory self-monitoring: A qualitative study of usability, convenience, and patient confidence.

Background: Remote photoplethysmography (rPPG) is a non-contact method for measuring physiological parameters using smartphone cameras. While the potential for scalable self-monitoring is promising, little is known about its usability and acceptability among patients with chronic cardiac and respiratory conditions. Objective: This qualitative study explored the user experiences of a smartphone-based rPPG app (Vitacam) to assess its usability, acceptability, and perceived utility in real-world conditions. Methods: Seven adults with chronic heart or respiratory conditions used the app at home over one week. Semi-structured interviews were conducted and explored using reflexive thematic analysis. Results: Participants appreciated the app's simplicity, real-time guidance, and convenience. Key barriers included environmental sensitivity (e.g. lighting), technical limitations, vague error messaging, and lack of clinical integration. Users valued basic self-monitoring features but expressed concerns about accuracy and interpretation, especially for complex conditions like atrial fibrillation. Conclusions: rPPG via smartphone is a promising, low-burden option for basic self-monitoring in chronic disease management. To increase adoption and utility, future iterations should improve feedback clarity, algorithm sensitivity, and integration with clinical systems. These developments could enhance user trust, accuracy, and long-term engagement.