Analysis of heart rate variability in patients with chronic rheumatoid arthritis
Background and Aim: Rheumatoid arthritis (RA) is one of the most common debilitating autoimmune disorders associated with morbidity and mortality. Apart from articular causes, the cardiovascular system plays an important role in untoward incidents of the disease. The cardiac risk in them can be estimated by analyzing the autonomic nervous system. Heart rate variability (HRV) analysis is reliable for testing the cardiac autonomic function. In the present study, we have planned to assess the HRV in RA patients and to compare it with the HRV of normal healthy individuals without RA. Methods: The study group (Group 1) comprised 50 patients of established RA (12 males and 38 females). The control group (Group 2) comprised 50 healthy age‑ and sex‑matched individuals (9 males and 41 females). Short‑term HRV recordings of 5 min were done using Multichannel Physiopac PP‑8 machine. Normalized low‑frequency power (LFnu), normalized high‑frequency power (HFnu), and low frequency/high frequency (LF/HF) ratio were analyzed using Kubios HRV software. Statistical analysis was done using Student’s t‑test. P < 0.05 was considered statistically significant. Results: When compared to control group, LFnu and LF/HF ratio increased significantly and HFnu decreased significantly in RA patients. Increase in LFnu shows predominant sympathetic activity, and decrease in HFnu shows parasympathetic attenuation. Conclusion: RA is associated with sympathovagal imbalance in the form of sympathetic overactivity and vagal withdrawal.