Abstract
Background: Chronic obstructive pulmonary disease (COPD) is the second most common cause of mortality in India. It is associated with cardiovascular dysautonomia. Heart rate (HR) variability is among the common non-invasive procedures to evaluate cardiac autonomic nervous activity.

Aims and Objectives: The aims of this study were to assess and compare HR variability in patients with COPD with healthy age- and sex-matched control subjects.

Materials and Methods: The cross-sectional study was performed in a tertiary care teaching institute (IEC No: 105/MC/EC/2020) from February 2021 to January 2022. A total of 60 individuals were studied with 30 COPD patients and 30 healthy age- and sex-matched persons as a control group. The unpaired student t-test was performed.

Results: The difference of mean height (cms, P ≤h0.09), mean age (P > 0.05), mean weight (P > 0.05), mean body mass index (P > 0.05), and mean HR (P > 0.05), between the two groups was non-significant. The mean (± SD) RR of cases and controls was 600 ± 312 and 756 ± 132, respectively. The difference among the two groups was statistically significant (P < 0.05). RMSSD and SDNN of both groups show an apparent decrease in the mean value of cases compared to healthy subjects (P = 0.02). The difference between pNN50 (P = 0.009) and NN50 (P = 0.02) among cases and controls was highly significant. The mean LF nu was higher (P = 0.002), mean HF nu was less (P = 0.001), and mean LF/HF was high (P = 0.03) among the cases than in the control group.

Conclusion: There is sympathetic hyperactivity and reduced parasympathetic activity in COPD patients as compared to healthy subjects, which is statistically significant. The study signifies the importance of non-invasive methods for screening autonomic function status in COPD patients.

Key words: Autonomic Functions; Cardiovascular; Chronic Obstructive Pulmonary Disease; Dysautonomia; Heart Rate Variability; Pulmonary