Abstract
Background: Alcohol-seeking behavior despite being aware of its adverse effects is defined as alcohol dependence (AD). AD syndrome is a cluster of physiological, behavioral, psychological, and perceptual phenomena that develop subsequent to chronic alcohol ingestion. Ethanol is a potent central nervous system depressant that causes toxic damage to the vasomotor and cardiac autonomic nerve fibers which leads to autonomic imbalance leading to arrhythmias and sudden cardiac deaths. Recording and analyzing the heart rate variability (HRV) using the frequency-domain method delineate the autonomic imbalance in alcoholic individuals which may be due to reduced parasympathetic activity and/or sympathetic hyperactivity.

Aims and Objectives: The aim of the study was to assess and compare the cardiac autonomic function between the AD group and the non-alcoholic control group using the frequency domain method of HRV.

Materials and Methods: A total of 55 alcohol-dependent individuals in the age group of 20–55 years were selected from the psychiatry outpatient department, based on the International Classification of Diseases-10 (Diagnostic and Statistical Manual -IV) criteria as the study population. Fifty-five age and gender-matched healthy volunteers from the master health check-up scheme from the Department of Community Medicine were selected as the control population. Institutional Ethical Committee clearance was obtained. After obtaining informed written consent from the individuals, the short-term 5 min HRV was recorded in the supine position with eyes closed. The results were analyzed and interpreted. Statistical analysis was done using the software Statistical Package for the Social Sciences version 21.0.

Results: The frequency domain parameters high frequency (HF) which is a specific marker of parasympathetic activity was significantly reduced, and low frequency (LF) which is a marker of sympathetic activity was significantly increased in the alcoholic group compared to the non-alcoholic group, respectively. The LF: HF ratio which denotes sympathetic-vagal balance was increased in the alcohol-dependent group.

Conclusion: HF was decreased, LF and LF: HF ratio was increased in alcoholic-dependent individuals indicating autonomic imbalance with reduced parasympathetic activity and increased sympathetic activity which suggests that alcohol affects the cardiac autonomic status. This concludes that the frequency domain method of HRV could be used as a short-term non-invasive test to assess cardiac autonomic dysfunction in alcohol-dependent individuals.

Key words: Heart Rate Variability; Frequency Domain Measures; Alcohol Dependence; Autonomic Imbalance; Cardiac Autonomic Neuropathy; Sympathovagal Imbalance