Table 2

Heart rate variability indexes in 22 female patients with fibromyalgia and 22 matched healthy controls.

24-hour

Sleeping hours

Fibromyalgia

Controls

P

value

Fibromyalgia

Controls

P

value

Mean NN (ms)

758.4 ± 70.9

796.5 ± 92.0

0.132

881.5 ± 94.8

915.6 ± 122.9

0.310

SDNN (ms)

133.7 ± 28.7

152.6 ± 32.8

0.047

91.2 ± 21.5

122.2 ± 32.0

0.001

SDANN (ms)

120.0 ± 28.1

132.5 ± 27.9

0.144

57.8 ± 19.2

83.2 ± 35.9

0.006

SDSD (ms)

36.0 ± 13.9

47.3 ± 16.9

0.020

45.9 ± 19.6

56.9 ± 21.3

0.084

RMSSD (ms)

36.0 ± 13.9

47.3 ± 16.9

0.020

45.9 ± 19.6

56.9 ± 21.3

0.084

pNN50 (%)

13.6 ± 10.3

20.5 ± 11.6

0.045

23.9 ± 17.5

31.4 ± 17.5

0.160

Holter recordings were analyzed for 24 hours, and during sleeping time (from 00.00 to 06.00 hours). Results are shown as mean ± standard deviation. Student's t test calculated the differences between fibromyalgia group and control group. Mean NN, mean NN interval; ms, milliseconds; pNN50, percentage of adjacent pairs of R-R intervals that differ by more than 50 ms from each other in a given time period; 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