Table 3.
Sensitivity, specificity, ROC curve, positive predictive value and negative predictive value for heart rate variability indices
| Indices | SEN | SPE | ROC | PPV | NPV |
|---|---|---|---|---|---|
| RMSSD | 0.66 [0.49 - 0.80] | 0.81 [0.66 - 091] | 0.79 [0.69 - 0.87] | 0.76 [0.58 - 0.89] | 0.72 [0.58 - 0.84] |
| SDNN | 0.57 [0.40 - 0.73] | 0.88 [0.74 - 0.96] | 0.80 [0.70 - 0.88] | 0.81 [0.61 - 0.93] | 0.70 [0.56 - 0.82] |
| PNN50 | 0.71 [0.55-0.85] | 0.72 [0.56-0.84] | 0.77 [0.66-0.85] | 0.70 [0.53-0.83] | 0.73 [0.58-0.83] |
| LF (ms2) | 0.79 [0.63 - 0.90] | 0.69 [0.53 - 0.82] | 0.75 [0.64 - 0.84] | 0.70 [0.54 - 0.83] | 0.75 [0.59 - 0.87] |
| HF (ms2) | 0.82 [0.66 - 0.92] | 0.55 [0.39 - 0.70] | 0.74 [0.63 - 0.83] | 0.62 [0.47 - 0.76] | 0.77 [0.58 - 0.90] |
| LF/HF (ms) | 0.84 [0.69 - 0.94] | 0.32 [0.19 - 0.48] | 0.56 [0.45 - 0.67] | 0.53 [0.40 - 0.66] | 0.70 [0.45 - 0.88] |
| LF nu | 0.84 [0.69 - 0.94] | 0.32 [0.19 - 0.48] | 0.56 [0.45 - 0.67] | 0.53 [0.40 - 0.66] | 0.70 [0.45 - 0.88] |
| HF nu | 0.84 [0.69 - 0.94] | 0.32 [0.19 - 0.48] | 0.56 [0.45 - 0.67] | 0.53 [0.40 - 0.66] | 0.70 [0.45 - 0.88] |
| TINN | 0.53 [0.37 - 0.69] | 0.79 [0.64 - 0.90] | 0.63 [0.52 - 0.74] | 0.70 [0.50 - 0.85] | 0.65 [0.50 - 0.78] |
| RRTri | 0.69 [0.52 - 0.83] | 0.76 [0.61 - 0.88] | 0.76 [0.65 - 0.85] | 0.73 [0.55 - 0.86] | 0.73 [0.58 - 0.85] |
| SD1 | 0.66 [0.49 - 0.80] | 0.79 [0.64 - 0.90] | 0.78 [0.68 - 0.87] | 0.74 [0.56 - 0.87] | 0.72 [0.57 - 0.84] |
| SD2 | 0.61 [0.44 - 0.76] | 0.88 [0.74 - 0.96] | 0.80 [0.70 - 0.88] | 0.82 [0.64 - 0.94] | 0.71 [0.57 - 0.83] |
| SD1/SD2 | 0.46 [0.30 - 0.62] | 0.76 [0.61 - 0.88] | 0.58 [0.46 - 0.68] | 0.64 [0.44 - 0.81] | 0.61 [0.46 - 0.74] |
| ApEn | 0.35 [0.21 - 0.52] | 0.86 [0.72 - 0.94] | 0.56 [0.44 - 0.67] | 0.70 [0.45 - 0.88] | 0.59 [0.46 - 0.71] |
SEN: sensitivity; SPE: specificity; PPV: positive predictive value; NPP: negative predictive value; SDNN: standard deviation of normal RR intervals in a time interval (ms); RMSSD: square root of the mean of the squares of successive differences between normal RR intervals in a time interval (ms); PNN50: percentage of adjacent RRIs that differ by more than 50 ms; TINN: triangular interpolation of RR intervals; RRTri: triangular index; LF: low-frequency component; HF: high-frequency component; nu: normalized unit; SD1: standard deviation of the instantaneous RR intervals; SD2: long-term variability of continuous RR intervals; ApEn: approximate entropy.