Reduced Heart Rate Variability in Patients with Chronic Obstructive Pulmonary Disease Independent of Anticholinergic or β-agonist Medications

ABSTRACT

Reduced heart rate variability (HRV) is a predictor of poor outcome in several pathologies and in general population. Whether HRV is altered during normal daily activities or influenced by anticholinergic and β-adrenergic medications in chronic obstructive pulmonary disease (COPD) remains unknown. Forty-one clinically stable COPD patients and 19 healthy controls matched for age, sex and smoking history underwent a 24-hour ambulatory ECG recording during normal daily activities. HRV was assessed by standardized temporal and spectral analysis. COPD patients showed a reduced HRV (LF/HF ratio) compared with healthy controls (median [interquartile range]) during daytime (2.6 [1.5–3.8] vs. 3.5 [2.9–5.6]), nighttime (1.8 [1.1–4.3] vs. 4.2 [2.7–6.9]) as well as during the entire 24-hour (1.9 [1.5–3.4] vs. 3.9 [3.2–5.6]) recordings (all P < 0.005). There was no significant difference between the two groups in the time domain and in the low frequency or high frequency domain for the 24-hour period analysis. In COPD patients, the 24-hour LF/HF ratio positively correlated with forced expiratory volume in 1 second (FEV₁) (r = 0.342, P = 0.028) and negatively correlated with age (r = −0.317, P = 0.044). In multiple regression analysis, LF/HF ratio was associated with FEV₁ (P = 0.05) but not with age (P = 0.08). There was no difference of HRV between patients using or not anticholinergic or β-agonist medications. These results demonstrate that COPD patients have a reduced sympatho-vagal balance compared with healthy subjects. HRV correlates with disease severity and does not seem to be influenced by anticholinergic or adrenergic medications.

Keywords: :

• Heart rate variability
• Chronic obstructive pulmonary disease
• FEV₁
• β-agonist
• Anticholinergic