Photoplethysmography wave morphology in patients with atrial fibrillation.

Most current algorithms for detecting atrial fibrillation (AF) rely on heart rate variability (HRV), and only a few studies analyse the variability of photopletysmography (PPG) waveform. This study aimed to compare morphological features of the PPG curve in patients with AF to those presenting a normal sinus rhythm (NSR) and evaluate their usefulness in AF detection.10 min PPG signals were obtained from patients with persistent/paroxysmal AF and NSR. Nine morphological parameters (1/Δ), Pulse Width [PW], augmentation index [AI], b/a, e/a, [b-e]/a, crest time [CT], inflection point area [IPA], Area and five HRV parameters (heart rate [HR], Shannon entropy [ShE], root mean square of the successive differences [RMSSD], number of pairs of consecutive systolic peaks [-] that differ by more than 50 ms [NN50], standard deviation of the-intervals [SDNN]) were calculated.Eighty subjects, including 33 with AF and 47 with NSR were recruited. In univariate analysis five morphological features (1/Δ,< 0.001; b/a,< 0.001; [b-e]/a,< 0.001; CT,= 0.011 and Area,< 0.001) and all HRV parameters (= 0.01 for HR and< 0.001 for others) were significantly different between the study groups. In the stepwise multivariate model (Area under the curve [AUC] = 0.988 [0.974-1.000]), three morphological parameters (PW,< 0.001; e/a,= 0.011; (b-e)/a,< 0.001) and three of HRV parameters (ShE,= 0.01; NN50,< 0.001, HR,= 0.01) were significant.There are significant differences between AF and NSR, PPG waveform, which are useful in AF detection algorithm. Moreover adding those features to HRV-based algorithms may improve their specificity and sensitivity.