Time and frequency domain analysis of heart rate variability in cattle affected by bovine spongiform encephalopathy

Table 4 Time domain indices and behaviour scores in the different groups based on the last ECG recording

Group^a	Heart rate [bpm] Median (range)	Deviation from mean interval [%] Median (range)	VVTI Median (range)	Behaviour scores: N animals^b
Female control	66 (45-109) N = 26	28.8% (7.8-84.7%) N = 25	10.8 (1.9-24.3) N = 25	0: 17 (65%) 1: 7 (27%) 2: 2 (8%)
Female negative	61 (40-154) N = 36	28.5% (2.9-91.7%) N = 35	8.9 (2.2-33.5) N = 35	0: 20 (59%) 1: 8 (23%) 2: 6 (18%)
Female positive	62 (32-89) N = 22	29.6% (6.7-140.9%) N = 21	9.1 (1.9-28.5) N = 21	0: 5 (23%) 1: 6 (27%) 2: 11 (50%)
Male control	66 (34-132) N = 50	29.8% (10.5-127.2%) N = 48	9.3 (2.5-22.6) N = 48	0: 38 (76%) 1: 11 (22%) 2: 1 (2%)
Male negative	67 (45-142) N = 288	24.8% (6.9-138.8%) N = 277	11.2 (1.5-28.5) N = 277	0: 208 (72%) 1: 57 (20%) 2: 22 (8%)
Male positive	65 (51-108) N = 28	28.1% (7.4-80.1%) N = 27	11.1 (3.2-20.3) N = 27	0: 12 (43%) 1: 4 (14%) 2: 12 (43%)
P -value ^c	ns (0.09)	ns (0.1)	ns (0.1)	Female groups: < 0.0001* Male groups: 0.003*

^a Negative: cattle inoculated with tissue/body fluids from BSE/scrapie-challenged or naturally infected BSE cases as well as reported BSE suspects that were negative for BSE by postmortem tests.
Positive: challenged or naturally infected BSE suspects that were positive for BSE by postmortem tests.
^b The behaviour score was not assessed in all animals with recorded ECGs.
^c Comparison of the heart time domain indices was done by Kruskal-Wallis test (ns = not significant), comparison of the behaviour scores within female and male cattle (score 0 versus scores 1 and 2) was done by Chi-square test.
* Significant differences between BSE-positive cattle and controls as well as BSE-positive and BSE-negative cattle after employing Bonferroni's correction (P < 0.03).

ISSN: 1756-0500