Cardiac autonomic dysfunction and health-related quality of life in patients with chronic obstructive pulmonary disease

Background and objective: COPD is associated with impaired health-related quality of life (HRQL) and cardiac autonomic dysfunction. Data describing the association between these factors in patients with COPD are mostly lacking. The objective of this study was to evaluate whether there is an association between cardiac autonomic dysfunction and HRQL in COPD. Methods: We studied 60 patients with COPD (37 women, mean (SD) age 65.20 (7.73) years, FEV1% pred. 46.58 (18.53) %) and measured HRQL, as assessed by the Chronic Respiratory Disease Questionnaire, and cardiac autonomic dysfunction, as assessed by heart rate variability (HRV). Analysis of HRV was performed using a Holter-ECG device during a recording period of 5 min. To evaluate a possible association between these factors, univariate and multivariate analyses were used. Results: There was a significant correlation between Chronic Respiratory Disease Questionnaire total score and both variables of HRV reflecting parasympathetic tone; root mean square successive difference of RR intervals (rMSSD) (r = 0.34, P = 0.012) and the density of the beat-to-beat oscillation in the N-N interval of HRV in the high-frequency band (HF power) (r = 0.35, P = 0.01). In a multivariate analysis rMSSD was found to be independently associated with HRQL after correcting for FEV1, carbon monoxide transfer coefficient (DLCO), 6MWD and CRP. Conclusions: Resting parasympathetic tone, as measured by HRV, is independently associated with HRQL, which emphasizes the role of cardiac autonomic dysfunction on HRQL in patients with COPD.