Cardiac Sympathetic Dominance and Systemic Inflammation in COPD

Figures & data

Table 1.  Demographic and lung function tests data

	COPD	Nonsmoker Controls	Smoker Controls
	(n = 63)	(n = 18)	(n = 18)
Age	55.5 ± 5.8^ns	52.4 ± 8.9	53.1 ± 5.8
BMI	20.5 ± 3.9^***	26.0 ± 3.8	22.184 ± 2.4
Pack years of smoking	39.4 ± 27.5^***	—	19.2 ± 15.2
FEV1/FVC ratio	44.6 ± 11.0^***	77.4 ± 5.4	78.1 ± 6.3
FEV1% predicted	54.1 ± 16.7^***	106.5 ± 24.0	105.0 ± 13.9
DLCOSB% predicted	66.2 ± 23.4^***	101.9 ± 20.7	105.2 ± 18.5
KCO% predicted	79.3 ± 28.3^***	112.1 ± 18.3	110.0 ± 17.3

Data expressed as mean ± SD; Comparisons of three groups using ANOVA, ***p < 0.0001, ns: not significant; FEV₁/FVC ratio and FEV₁% predicted are post-bronchodilator values.

Figure 1. The 5-minute averaged heart rate (beat per minute, bpm) in patients and controls (ANOVA p < 0.0001).

Figure 2. HRV parameters (SDNN, RMSDD, total power, LF modulation and HF modulation) in patients and controls. SDNN: standard deviation of all the NN intervals; RMSSD: root mean square of successive differences between adjacent NN intervals; LF modulation: power in the low frequency band, i.e., 0.04–0.15 Hz; HF modulation: power in the high frequency band, i.e., 0.15–0.4 Hz; Units: SDNN and RMSDD in ms and total power, LF modulation and HF modulation in ms²; values are natural log- transformed; *p < 0.05, ***p < 0.001, + 0.05 > p < 0.10.

Table 2.  Heart rate variability indices in the three groups

HRV Indices	COPD	Nonsmoker Controls	Smoker Controls
	(n = 63)	(n = 18)	(n = 18)
Time domain indices
Ln SDNN (ms)	3.8 ± 0.5*	3.73 ± 0.5	3.48 ± 0.5
Ln RMSSD (ms)	3.66 ± 0.6*	3.46 ± 0.8	3.15 ± 0.8
Ln pNN50	1.58 ± 0.9^ns	1.48 ± 1.1	1.44 ± 1.2
Frequency domain indices
Ln Total Power (ms^2)	7.68 ± 1.0*	7.34 ± 1.2	6.94 ± 0.9
Ln LF (ms^2)	6.54 ± 1.3^***	6.04 ± 1.2	5.19 ± 0.9
Ln LFnu (ms^2)	3.86 ± 0.7^ns	3.64 ± 0.5	3.63 ± 0.6
Ln HF (ms^2)	6.14 ± 1.4*	6.06 ± 1.1	5.14 ± 1.4
Ln HFnu (ms^2)	3.52 ± 0.7^ns	3.59 ± 0.3	3.59 ± 0.5
Ln LF/HF Ratio	0.19 ± 1.0^ns	0.05 ± 0.6	0.06 ± 1.1

Data shown in natural log transformed values expressed as mean ± SD, Comparisons of three groups using ANOVA, ***p < 0.0001, *p < 0.05, ns: not significant; Between-group comparisons presented in text under the results section; SDNN (standard deviation of all the NN intervals), RMSSD (root mean square of successive differences between adjacent NN intervals), pNN50 (percentage of number of NN interval with difference ≥ 50 ms), Total power (area under the spectral curve from 0.01 to 0.4 Hz), LF (power in the low frequency band 0.04–0.15 Hz), LFnu (low frequency power divided by the balance of TP-very low frequency), HF (power in the high frequency band i.e. 0.15–0.4 Hz), HFnu (high frequency power divided by the balance of TP-very low frequency), LF/HF ratio (low to high frequency power ratio).

Table 3.  Heart rate and heart rate variability indices by GOLD severity and by quartiles of BODE index scores

HRV Indices	GOLD Severity		BODE Index Quartiles
	Mild-Moderate	Severe-Very Severe	Q1	Q2	Q3	Q4
Heart Rate (beat/minute)	82.1 ± 12.1	85.8 ± 11.4^ns	82.9 ± 10.8	84.4 ± 7.3	82.7 ± 14.5	84.4 ± 13.5^ns
Ln SDNN (ms)	3.73 ± 0.5	3.9 ± 0.4^ns	3.76 ± 0.4	3.68 ± 0.7	3.92 ± 0.5	3.83 ± 0.3^ns
Ln RMSSD (ms)	3.52 ± 0.7	3.85 ± 0.5*	3.56 ± 0.4	3.49 ± 0.8	3.71 ± 0.8	3.79 ± 0.4^ns
Ln pNN50	1.42 ± 0.9	1.8 ± 0.8^ns	1.36 ± 0.9	1.34 ± 0.7	1.86 ± 1.0	1.68 ± 0.8^ns
Ln Total Power (ms^2)	7.5 ± 1.0	7.92 ± 0.9^ns	7.6 ± 0.9	7.31 ± 1.3	7.96 ± 1.1	7.78 ± 0.8^ns
Ln LF (ms^2)	6.33 ± 1.3	6.83 ± 1.3^ns	6.53 ± 1.1	5.97 ± 1.6	7 ± 1.4	6.59 ± 1.24^ns
Ln LFnu (ms^2)	3.82 ± 0.5	3.92 ± 0.9^ns	3.83 ± 0.4	3.8 ± 0.6	3.92 ± 0.4	3.88 ± 1.1^ns
Ln HF (ms^2)	5.89 ± 1.6	6.46 ± 1.2^ns	6.06 ± 1.1	5.65 ± 1.8	6.41 ± 1.7	6.31 ± 1.2^ns
Ln HFnu (ms^2)	3.4 ± 0.8	3.67 ± 0.4^ns	3.55 ± 0.4	3.12 ± 1.2	3.53 ± 0.6	3.73 ± 0.5^ns
Ln LF/HF Ratio	0.31 ± 1.0	0.04 ± 0.8^ns	0.58 ± 0.7	0.11 ± 1.3	0.39 ± 0.9	−0.14 ± 0.9^ns

Data shown in natural log transformed values expressed as mean ± SD, *p < 0.05, ns: not significant; GOLD severity categories compared by Students's t-test, BODE index score quartiles compared by ANOVA. SDNN (standard deviation of all the NN intervals), RMSSD (root mean square of successive differences between adjacent NN intervals), pNN50 (percentage of number of NN interval with difference ≥ 50 ms), Total power (area under the spectral curve from 0.01 to 0.4 Hz), LF (power in the low frequency band 0.04–0.15 Hz), LFnu (low frequency power divided by the balance of TP-very low frequency), HF (power in the high frequency band, i.e., 0.15–0.4 Hz), HFnu (high frequency power divided by the balance of TP-very low frequency), LF/HF ratio (low to high frequency power ratio).

Figure 3. Relationship between heart rate and single-breath diffusion capacity for carbon monoxide (DLCO_SB% predicted).

Figure 4. Levels of serum C-reactive protein (CRP) expressed in mg/L, and interleukin 6 (IL-6) expressed in pg/ml, in patient and control groups. (ANOVA p < 0.05 for both).