Wearable device and method of detecting atrial fibrillation

A method of detecting atrial fibrillation, the method comprising:

• obtaining a photoplethysmogram (PPG) signal from a first sensor of a wearable device;
• obtaining a motion detection signal from a second sensor of the wearable device;
• determining whether there is motion exceeding a reference value, based on the motion detection signal;
• detecting a heart rate from the PPG signal based on a peak-peak interval (PPI) of the PPG signal when the motion does not exceed the reference value and based on power spectrum analysis in a frequency domain of the PPG signal when the motion exceeds the reference value;
• and
• detecting atrial fibrillation based on the heart rate.

A wearable device comprising:

• a first sensor configured to sense a pulse wave of a user and generate a photoplethysmogram (PPG) signal based on the pulse wave;
• a second sensor configured to sense motion of the user and generate a motion detection signal;
• a memory storing program code;
• and
• at least one processor configured to access the memory to execute the program code,
• wherein the program code causes at least one of the at least one processor to detect a heart rate based on a peak-peak interval (PPI) of the PPG signal when the second sensor senses no motion and based on power spectrum analysis of the PPG signal in a frequency domain when the second sensor senses the motion, and
• wherein the program code causes at least one of the at least one processor to detect atrial fibrillation based on the heart rate.