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Table 3 Heart rate variability and urine catecholamine: patients with and without CPAP treatment

From: Nocturnal CPAP improves walking capacity in COPD patients with obstructive sleep apnoea

Heart rate variability

Overlap syndrome n = 18#

 

COPD

 

n = 20@

 

Baseline

With CPAP

p

Baseline

With CPAP

p

LF (nu)

46.6 ± 16.1

31.3 ± 16.7

0.001

31.8 ± 10.8*

28.7 ± 20.4

0.401

HF (nu)

32.2 ± 12.0

43.1 ± 19.1

0.029

41.9 ± 12.1*

43.6 ± 19.3

0.287

LF/HF

1.8 ± 1.2

0.9 ± 0.7

0.003

0.9 ± 0.6*

1.2 ± 1.9

0.514

Urine catecholamines

Overlap syndrome n = 12 $

 

COPD

 

n = 12 $

 

Baseline

With CPAP

 

Baseline

With CPAP

 

Norepinephrine, ug

17.0 ± 8.4

10.4 ± 6.4

0.003

11.1 ± 5.3*

11.9 ± 7.5

0.485

Epinephrine, ug

2.4 ± 0.9

1.4 ± 0.7

0.025

1.5 ± 0.6*

1.8 ± 0.8

0.374

  1. *P < 0.05; when compared with baseline overlap syndrome group.
  2. P values represent comparisons between before and after CPAP in each corresponding group.
  3. LF low frequency, HF high frequency nu normalized unit.
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Respiratory Research

ISSN: 1465-993X

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