Comparison of time domain indices of heart rate variability between alcohol-dependent individuals and non-alcoholic subjects

Abstract

Background: Alcohol dependence develops because of repeated alcohol intake. Alcohol damages the cardiac autonomic nerve fibers leading to autonomic imbalance, resulting in reduced heart rate variability (HRV). HRV refers to the complex beat-to-beat variation in the heart rate, produced by the interplay of sympathetic and parasympathetic neural activity at the Sino-atrial node. Our body works effectively in parasympathetic activity dominance. The time domain indices of HRV are specific markers of parasympathetic activity. A decrease in the time domain parameters indicates reduced parasympathetic activity in the heart, indicating cardiac autonomic dysfunction with vagal neuropathy. Aims and Objectives: The objectives of the study are as follows: (1) To assess the HRV in alcohol-dependent individuals using time domain indices. (2) To compare the HRV between alcoholic-dependent individuals and non-alcoholic subjects. Materials and Methods: A total of 110 individuals in the age group of 20–55 years were recruited for our study. Among them, 55 were alcohol-dependent individuals selected based on the diagnostic and statistical manual-IV, international classification of diseases-10 criteria, and 55 age and gender-matched volunteers were selected as healthy non-alcoholic controls. Short-term HRV was recorded in a supine posture, and the results were interpreted. Statistical analysis was done using the software SPSS version 21.0. Results: Our results showed a significant reduction in the time-domain parameters of HRV – SDNN, RMSSD, NN50, and pNN50 in the alcohol-dependent individuals compared to the controls, suggesting reduced parasympathetic activity in the heart indicating cardiac autonomic neuropathy. Conclusion: Alcohol affects the cardiac autonomic status leading to sudden death due to arrhythmias. HRV can be used as a non-invasive test to assess cardiac autonomic dysfunction and its biofeedback can help alcohol-dependent individuals to adopt healthy lifestyle measures.