Altered cardiac rhythm in infants with bronchiolitis and respiratory syncytial virus infection

BMC Infectious Diseases

Table 3 Heart rate variability in infants with bronchiolitis, by etiology.

Variable	Admission		28 ± 3 days after admission
	RSV-positive (n = 34)	RSV-negative (n = 35)	RSV-positive (n = 34)	RSV-negative (n = 35)
Sinoatrial block, No. (%)	26 (76.5)°^	1 (2.9)	0 (0.0)	0 (0.0)
Sinoatrial block 1-2 sec., No. (%)	21 (61.8)°^	1 (2.9)	0 (0.0)	0 (0.0)
Sinoatrial block > 2 sec., No. (%)	5 (14.7)*"	0 (0.0)	0 (0.0)	0 (0.0)
More than 3 sinoatrial blocks, No. (%)	25 (96.2)°^	0 (0.0)	0 (0.0)	0 (0.0)
Mean heart rate, bpm ± SD	139.23 ± 15.7*"	116.65 ± 15.9	119.37 ± 19.6	112.06 ± 10.1
Maximum heart rate, mean bpm ± SD	204.29 ± 20.6*"	173.30 ± 28.8	179.49 ± 21.8	170.10 ± 21.3
Minimum heart rate, mean bpm ± SD	49.62 ± 17.1	45.61 ± 26.10	49.31 ± 19.45	48.44 ± 20.14
SDNN (ms), mean ± SD	58.34 ± 26.37	54.61 ± 24.11	56.46 ± 22.21	55.39 ± 22.68
SDANN (ms), mean ± SD	49.61 ± 28.75	45.57 ± 25.70	47.66 ± 25.55	46.91 ± 26.96
ASDNN (ms), mean ± SD	37.11 ± 17.20	33.33 ± 13.70	35.64 ± 18.52	34.39 ± 16.31
rMSSD (ms), mean ± SD	20.31 ± 19.55	19.30 ± 16.99	19.25 ± 19.43	19.77 ± 19.03
PNN50, mean % ± SD	4.21 ± 7.2	2.93 ± 4.5	3.33 ± 5.3	3.22 ± 4.9
LF (ms²), mean ± SD	636.13 ± 306.7*"	369.48 ± 276.7	373.49 ± 269.73	369.55 ± 288.76
LF (nu), mean ± SD	33.93 ± 6.8*"	24.91 ± 5.6	25.01 ± 5.9	24.99 ± 6.1
HF (ms²), mean ± SD	271.06 ± 573.5	106.09 ± 152.5	143.9 ± 155.5	176.73 ± 169.6
HF (nu), mean ± SD	7.10 ± 7.6	6.76 ± 2.8	6.76 ± 4.5	6.85 ± 4.9
LF/HF ratio, mean ± SD	4.78 ± 1.60*"	3.68 ± 1.48	3.69 ± 1.40	3.64 ± 1.55

SD: standard deviation; bpm: beats per minute; SDNN: standard deviation of all NN intervals; SDANN: standard deviation of the average of NN intervals in all 5-minute segments of the 24-h recording; ASDNN: mean of the standard deviation in all 5-minute segments of the 24-h recording; rMSSD: square root of the mean of the squares of the differences between adjacent NN intervals; pNN50: percentage of differences between adjacent NN intervals of > 50 msec; LF: low-frequency power; HF: high-frequency power; nu: normalised units.
°p < 0.0001 and *p < 0.05 for the comparison between groups (i.e., RSV-positive vs RSV-negative upon admission); ^p < 0.0001 and "p < 0.05 for the comparison within group (i.e., admission vs 28 ± 3 days after admission in the RSV-positive group); no other significant difference between or within-group.

ISSN: 1471-2334