Research Article

Extraction of Heart Rate Variability from Smartphone Photoplethysmograms

Table 3

Bland-Altman analysis of HRV parameters derived from the smartphone and the electrocardiograph.

ParameterPPVPM1DM2DTI

AVNN (ms)−0.05 ± 0.68*
BAR = 0.07%
−0.12 ± 0.54*
BAR = 0.06%
−0.06 ± 0.55*
BAR = 0.06%
−0.05 ± 0.55*
BAR = 0.04%
−0.09 ± 0.51*
BAR = 0.05%

SDNN (ms)28.39 ± 31.26 
BAR = 41.85%
18.40 ± 15.48 
BAR = 22.21%
13.03 ± 12.85 
BAR = 19.17%
22.65 ± 12.85 
BAR = 25.51%
12.76 ± 14.37 
BAR = 21.49%

CV (%)2.95 ± 2.96 
BAR = 37.53%
1.99 ± 1.81 
BAR = 24.47%
1.41 ± 1.48 
BAR = 20.79%
2.45 ± 1.48 
BAR = 28.48%
1.39 ± 1.66 
BAR = 23.32%

RMSSD (ms)67.84 ± 61.35 
BAR = 70.14%
46.77 ± 35.77 
BAR = 46.50%
33.96 ± 29.77 
BAR = 42.22%
57.44 ± 29.77 
BAR = 47.93%
32.95 ± 33.85 
BAR = 48.35%

SDSD (ms)67.95 ± 61.47 
BAR = 70.17%
46.84 ± 35.83 
BAR = 46.50%
34.01 ± 29.82 
BAR = 42.21%
57.53 ± 29.82 
BAR = 47.92%
33.00 ± 33.91 
BAR = 48.35%

NN5057.57 ± 57.65 
BAR = 81.98%
45.53 ± 53.24 
BAR = 82.80%
41.20 ± 54.79 
BAR = 88.18%
57.87 ± 54.79 
BAR = 88.22%
37.67 ± 52.02 
BAR = 86.17%

pNN50 (%)17.88 ± 17.79 
BAR = 79.07%
13.87 ± 15.82 
BAR = 77.17%
12.47 ± 15.82 
BAR = 79.91%
12.47 ± 15.82 
BAR = 79.91%
12.47 ± 15.82 
BAR = 79.91%

TP (ms2)23.82 ± 63.56 
BAR = 3.82%
14.55 ± 75.59 
BAR = 4.56%
20.67 ± 56.93*
BAR = 3.42%
0.52 ± 56.93*
BAR = 2.55%
17.10 ± 53.88*
BAR = 3.24%

VLF (ms2)6.30 ± 81.19 
BAR = 18.96%
8.08 ± 93.97 
BAR = 21.90%
4.25 ± 67.45*
BAR = 15.79%
4.36 ± 67.45*
BAR = 14.66%
4.10 ± 67.97*
BAR = 15.91%

LF (ms2)−1.22 ± 113.36 
BAR = 16.83%
−7.05 ± 128.70 
BAR = 19.19%
−1.77 ± 81.75*
BAR = 12.14%
−5.67 ± 81.75*
BAR = 11.89%
−3.39 ± 78.84*
BAR = 11.73%

HF (ms2)18.69 ± 75.18*
BAR = 13.82%
16.59 ± 88.85*
BAR = 16.37%
17.98 ± 55.56*
BAR = 10.22%
2.71 ± 55.56*
BAR = 9.69%
17.12 ± 60.00*
BAR = 11.05%

LF/HF−0.09 ± 0.34 
BAR = 24.89%
−0.10 ± 0.33 
BAR = 24.55%
−0.09 ± 0.26 
BAR = 19.30%
−0.06 ± 0.26 
BAR = 18.35%
−0.09 ± 0.26 
BAR = 19.13%

nLF (%)−1.50 ± 5.75*
BAR = 10.72%
−1.30 ± 6.56*
BAR = 12.19%
−1.36 ± 4.89*
BAR = 9.09%
−0.60 ± 4.89*
BAR = 6.98%
−1.28 ± 4.93*
BAR = 9.16%

nHF (%)1.37 ± 5.68*
BAR = 12.55%
1.25 ± 5.10*
BAR = 11.28%
1.23 ± 4.53*
BAR = 10.01%
0.62 ± 4.53*
BAR = 7.58%
1.20 ± 4.28*
BAR = 9.46%

SD1 (ms)48.05 ± 43.47 
BAR = 70.17%
33.12 ± 25.33 
BAR = 46.50%
24.05 ± 21.08 
BAR = 42.21%
40.68 ± 21.08 
BAR = 47.92%
23.33 ± 23.97 
BAR = 48.35%

SD2 (ms)14.35 ± 17.58 
BAR = 21.12%
8.98 ± 7.49 
BAR = 9.30%
6.54 ± 6.51*
BAR = 8.21%
10.50 ± 6.51 
BAR = 11.79%
6.47 ± 6.74*
BAR = 8.50%

Data are presented as bias ± 1.96 standard deviation (SD). *Bias ± 1.96 SD within the acceptable limits. BAR: Bland-Altman ratio, PP: peak point, VP: valley point, M1D: maximum first derivative, M2D: maximum second derivative, and TI: tangent intersection. HRV parameters are explained in Table 1.