Journal of AdvancedMedical and Dental Sciences Research

Background: Chronic imbalance of the autonomic nervous system is prevalent and potent risk factor for adverse cardiovascular events including mortality. The present study was conducted to assess heart rate variability in hypertensive and normotensive subjects. Materials & Methods: 60 hypertensive and 60 normotensive subjects was included. Total power (TP), normalized low frequency power (LFnu), normalized high frequency power (HFnu), ratio of low frequency power to high frequency power (LF-HF ratio), standard deviation of normal-to-normal RR intervals (SDNN), root mean square successive difference (rMSSD) and the proportion of NN50 to the total number of NN intervals (pNN50) were assessed. Results: SDNN (ms) was 156.2 in group I and 142.6 in group II, pNN50 was 14.5 in group I and 11.7 in group II, rMSSD (ms) was 42.6 in group I and 39.0 in group II. LFnu was 74.0 in group I and 84.5 in group II, HFnu was 56.2 in group I and 34.9 in group II and LF/HF ration was 2.7 in group I and 3.6 in group II. The difference was significant (P< 0.05). Conclusion: Hypertensive patients exhibited decreased heart rate variability and decreased parasympathetic modulation as compared to normotensive subjects.