Heart rate variability reflects severity of COPD in PiZ α1-antitrypsin deficiency

Background: Analysis of heart rate variability (HRV) is a powerful method of assessing severity of conditions affecting the autonomic nervous system. Study objective: To determine if HRV is decreased and if HRV reflects severity in COPD. Design: Prospective determination of HRV from 24-h outpatient Hotter recordings. Patients: Eighteen individuals with PiZ alpha(1)-antitrypsin deficiency: 13 with COPD and 5 with normal FEV1. HRV was also determined in 18 matched normal control subjects. Approximately 3 years after the initial recording, all COPD subjects were contacted to determine current status, Measurements: Indexes of heart rate (HR) and HRV were compared for groups of patients with and without COPD and their control subjects. Results: Mean and minimum HRs were higher in COPD patients. Virtually all indexes of HRV were significantly decreased in COPD patients, No differences were found in IIR or HRV between PiZ individuals with normal FEV1 and their age- and gender-matched control subjects. Patients who had a change in status (ie, death, lung transplant, listed for transplant) had significantly higher day-time HRs, lower values for HRV indexes reflecting mixed sympathetic and parasympathetic modulation of HR, and reduced daytime high-frequency spectral power, an index of cardiac vagal modulation. Significant correlations (r=0.48 to 0.88) were found between FEV, and these and other indexes of HRV. Most other indexes of HRV also tended to be lower for the group whose status had changed. Conclusion: PiZ alpha(1)-antitrypsin deficiency COPD is associated with abnormal cardiac autonomic modulation. Indexes of HRV appear to reflect severity and may have prognostic value in COPD patients.