Clinical Validation of Heart Rate Apps: Mixed-Methods Evaluation Study

Area of Science:

• Biomedical Engineering
• Digital Health
• Cardiovascular Technology

Background:

• Photoplethysmography (PPG) enables smartphone-based heart rate (HR) monitoring, offering scalable mobile health solutions.
• Current validation methods for HR apps lack standardization, leading to inconsistent accuracy assessments compared to clinical standards.

Purpose of the Study:

• To investigate and define essential elements for validating and comparing smartphone HR applications against established technologies.
• To establish a reliable methodology for assessing the accuracy of mobile HR monitoring solutions.

Main Methods:

• Two prospective studies utilized the FibriCheck app, comparing its HR measurements against FDA-cleared devices (Nonin oximeter, AliveCor ECG).
• A beat-to-beat interval analysis was performed, comparing FibriCheck's peak-to-peak intervals (PPI) with synchronized ECG R-R intervals (RRI).

Main Results:

• The first study showed high HR correlation (r=0.834-0.897) between FibriCheck and clinical devices, with no significant differences.
• The second study demonstrated a strong correlation (rs=0.993) and low error (RMSE=23.04 ms) between FibriCheck PPI and ECG RRI, with no significant difference.

Conclusions:

• Simultaneous HR measurement by a smartphone app and an ECG system, analyzed via beat-to-beat intervals, is the most suitable validation method.
• This approach enhances the accuracy of HR app assessments, promoting reliable mobile cardiovascular monitoring.