PPG signal processing device and corresponding computer-implemented method

A photoplethysmography signal processing device, abbreviated as PPG signal processing device, configured to detect atrial flutter, said PPG signal processing device comprising at least one processor and at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the PPG signal processing device to:

• obtain at least one photoplethysmography signal (200), abbreviated as PPG signal, for a human or animal;
• detect heartbeats in said at least one PPG signal;
• determine interbeat intervals for pairs of consecutive heartbeats in said at least one PPG signal;
• detect interbeat interval baselines, each interbeat interval baseline corresponding to a plurality of consecutive interbeat intervals that are substantially constant;
• determine respective average interbeat interval values for respective ones of said interbeat interval baselines;
• and
• detect arterial flutter by detecting the existence of a relationship between said average interbeat interval values as follows:
• determine respective distances between said average interbeat interval values of said interbeat interval baselines and nearest atrial lines for a subset of atrial rates, wherein said subset of atrial rates comprises integer beat per minute values between a lower bound and an upper bound and wherein atrial lines correspond to integer parts of said atrial rates;
• determine for each atrial rate in said subset of atrial rates an average distance between said average interbeat interval values and nearest atrial lines for said atrial rate;
• select the atrial rate for which said average interbeat interval values have the smallest average distance to the atrial lines;
• and
• detect atrial flutter if said smallest average distance is smaller than a predetermined threshold distance.