Table 4 

Predictive value of heart rate variability indexes in 22 patients with fibromyalgia and 22 controls. 

Sensitivity (%) 
Specificity (%) 
PPV (%) 
NPV (%) 



24hour 



Mean NN ≤ 779 ms 
73 
55 
62 
67 
SDNN ≤ 141 ms 
68 
68 
68 
68 
SDANN ≤ 119 ms 
64 
68 
67 
65 
SDSD ≤ 40 ms 
64 
68 
67 
65 
RMSSD ≤ 40 ms 
64 
68 
67 
65 
pNN50 ≤ 13% 
55 
73 
67 
62 


Sleeping hours 



Mean NN ≤ 922 ms 
73 
59 
64 
68 
SDNN ≤ 114 ms 
86 
68 
73 
83 
SDANN ≤ 59 ms 
68 
82 
79 
72 
SDSD ≤ 44 ms 
55 
73 
67 
62 
RMSSD ≤ 44 ms 
55 
73 
67 
62 
pNN50 ≤ 31% 
68 
55 
60 
63 


Mean NN, mean NN interval; pNN50, percentage of adjacent pairs of RR intervals that differ by more than 50 ms from each other in a given time period; ms, milliseconds; RMSSD, square root of the mean of the squares of differences between adjacent NN intervals; SDANN, mean standard deviation of the average NN intervals calculated over 5 minutes; SDNN, standard deviation of the NN intervals; SDSD, standard deviation of the successive NN differences. 

Lerma et al. Arthritis Research & Therapy 2011 13:R185 doi:10.1186/ar3513 