Changes in deceleration capacity of heart rate and heart rate variability induced by ambient air pollution in individuals with coronary artery disease

Table 2 Description and correlation of analyzed ECG-Parameters.

Variable	N	Mean (± SD)	Min.	25%	Median	75%	Max.	IQR	Spearman correlation coefficient^a
5 minutes spontaneous breathing in supine position
									HR	HF power	HFn	LF power	LFn
HR [beats/min]	625	64.7 (± 9.9)	46.6	56.9	63.1	70.1	103.5	13.2	1
HF power [ms²]	625	669.9 (± 3348.4)	3.6	16.4	40.4	202.4	70263	185.9	-0.4	1
HFn [n.u.]	625	0.2 (± 0.2)	0.0	0.1	0.2	0.3	0.9	0.3	-0.1	0.5	1
LF power [ms²]	625	519.2 (± 1378.3)	3.3	63.4	145.5	357.8	21807.3	294.4	-0.4	0.7	0.1	1
LFn [n.u.]	625	0.4 (± 0.2)	0.0	0.2	0.4	0.6	1.0	0.3	-0.2	-0.1	0.30	0.3	1
RMSSD [ms]	625	40.8 (± 52.9)	4.5	14.7	22.3	40.7	462.4	26.0	-0.4	0.7	0.4	0.6	0.0
24-hour recordings
									HR	SDNN	RMSSD	pNN50
HR [beats/min]	254	69.3 (± 9.0)	50.4	62.7	69.0	74.7	94.2	12.0	1
SDNN [ms]	254	124.9 (± 33.6)	59.8	101.3	122.6	147.0	222.7	45.7	-0.4	1
RMSSD [ms]	254	42.9 (± 34.9)	9.9	22.2	31.3	49.8	292.1	27.6	-0.5	0.4	1
pNN50 [%]	254	2.8 (± 3.9)	0.0	0.0	1.0	4.0	18.0	4.0	-0.5	0.6	0.8	1
DC [ms]	254	5.6 (± 2.6)	0.3	3.8	5.3	7	21.1	3.2	-0.7	0.4	0.4	0.3

SD: standard deviation; IQR: interquartile range; HR: heart rate, HF: high-frequency, HFn: normalized high-frequency; n.u.: no unit; LF: low-frequency, LFn: normalized low-frequency; RMSSD: square root of the mean square of successive differences of normal-to-normal (NN) intervals, SDNN: standard deviation of NN intervals, pNN50: percentage of adjacent NN intervals which differ more than 50 ms, DC: deceleration capacity.
^aMedian of patient-specific Spearman correlation coefficients.

ISSN: 1743-8977