A Comprehensive Study of Autonomic Dysfunction in Hypertension by Assessing Autonomic Function Tests and HRV

Aims To study the variations of autonomic nervous system in hypertensive patients using a set of autonomic function tests and to correlate cardiac autonomic function with Heart rate variability in hypertensives. Background The pathophysiological mechanism for the development of hypertension is the lack of balance between sympathetic and parasympathetic nervous system. Both Heart rate variability (HRV) and Autonomic function tests provide a tool to know the concept of autonomic modulation of heart. They also forms an index of cardiac autonomic regulation. Methods The study included 50 hypertensive patients and 50 normotensive subjects. All the subjects underwent for the analysis of heart rate variability in time domain (TD) and frequency domain and a set of autonomic function tests were done to assess the autonomic functions. These results were compared with age and sex matched controls (normotensives). The subjects were selected based on exclusion-inclusion criteria. Results Results showed that S L ratio, Valsalva ratio & Heart rate response to deep breathing test values were decreased in Hypertensives as compared to Normotensives (pless than0.05). Isometric handgrip exercise, BP response to standing and cold pressor tests shows that there was significant rise in the systolic and diastolic blood pressure in Hypertensives as compared to Normotensives which was statistically significant (pless than0.05). Both the time domain and frequency domain values of HRV reduced significantly in hypertensives indicated that there is increased sympathetic activity and decreased parasympathetic activity. Conclusion From this study, it is evident that Hypertension can alter the normal autonomic functions of the body and predisposes to autonomic neuropathy. Early and regular screening of these individuals is necessary to prevent any future complications.