
AUC (95% CI)

Pvalue^{a}

Best cutoff value

Distance to optimum value (0,1)


24hour
    
Mean NN (ms)

0.61 (0.45  0.79)

0.18

779

0.53

SDNN (ms)

0.67 (0.50  0.83)

0.05

141

0.45

SDANN (ms)

0.64 (0.48  0.81)

0.11

119

0.48

SDSD (ms)

0.69 (0.53  0.84)

0.03

40

0.48

RMSSD (ms)

0.69 (0.53  0.84)

0.03

40

0.48

pNN50 (%)

0.68 (0.52  0.83)

0.04

13

0.53

Sleeping hours
    
Mean NN (ms)

0.59 (0.41  0.77)

0.30

922

0.49

SDNN (ms)

0.79 (0.66  0.92)

0.00

114

0.35

SDANN (ms)

0.75 (0.60  0.897)

0.00

59

0.37

SDSD (ms)

0.64 (0.48  0.81)

0.09

44

0.53

RMSSD (ms)

0.64 (0.48  0.81)

0.09

44

0.53

pNN50 (%)

0.63 (0.47  0.80)

0.13

31

0.55

 ^{a}Null hypothesis is that area under the curve = 0.5.
 Holter recordings were analyzed for 24 hours, and during sleeping time (from 00.00 to 06.00 hours). AUC, area under the curve; CI, confidence interval; Mean NN, mean NN interval; SDNN, standard deviation of the NN intervals; SDANN, mean standard deviation of the average NN intervals calculated over 5 minutes; ms, milliseconds; SDSD, standard deviation of the successive NN differences; RMSSD, square root of the mean of the squares of differences between adjacent NN intervals; pNN50, percentage of adjacent pairs of RR intervals that differ by more than 50 ms from each other in a given time period.