Accuracy of Apple Watch to Measure Cardiovascular Indices in Patients with Cardiac Diseases: Observational Study

Area of Science:

• Cardiology
• Biomedical Engineering
• Wearable Technology

Background:

• The clinical utility of consumer wearables like the Apple Watch for physiological monitoring in cardiac patients remains under investigation.
• Accurate measurement of heart rate (HR) and oxygen saturation (SpO2) is crucial for managing cardiovascular conditions.

Purpose of the Study:

• To evaluate the validity and accuracy of the Apple Watch for measuring HR and SpO2 in patients with cardiac diseases.
• To assess Apple Watch performance across different conditions: rest, exercise, and recovery, in patients with regular and irregular heart rhythms.

Main Methods:

• A cross-sectional study involving 260 cardiac patients (190 with regular rhythm, 70 with arrhythmia).
• Concurrent measurements using Apple Watch against a Polar HR monitor and a Contec pulse oximeter.
• Data collected at rest, during, and after mild- to moderate-intensity exercise sessions.

Main Results:

• The Apple Watch demonstrated excellent validity for HR measurement at rest, during exercise, and post-exercise (ICC=0.100).
• Excellent validity was observed for SpO2 at rest (ICC=0.100) and post-exercise (ICC=0.92).
• Slightly reduced SpO2 validity (ICC=0.85) was noted post-exercise, particularly in patients with cardiac arrhythmia.

Conclusions:

• The Apple Watch is a valid tool for measuring HR and SpO2 in cardiac patients under resting and post-exercise conditions.
• HR monitoring with Apple Watch is reliable during mild- to moderate-intensity exercise.
• While generally accurate, SpO2 measurements may be less precise in patients with irregular heart rhythms after exercise.