ALTERED AUTONOMIC BALANCE IN NORMAL TENSION GLAUCOMA
Objective: To study autonomic imbalance if any in normal tension glaucoma (NTG)patients by heart rate variability (HRV)and head-up tilt (HUT)test.
Methods: The study subjects of age between 45 and 65 years of either sex comprised 20 patients with NTG (Group Ð†Ð†)and 20 age- and sex-matched healthy controls (Group Ð†). Different variables of time and frequency domain of HRV were analyzed at rest, during HUT and the recovery period.
Results: Highly significant decrease in value of root mean square successive difference observed in Group Ð†Ð† (p<0.000)in comparison to controls. The high-frequency variables (HF [nu]and HF [ms2])were significantly less (p<0.000)and low frequency (LF)/HF ratio was significantly high (p<0.000) in Group Ð†Ð†.
Conclusion: During stress test, i.e., HUT there was the greater withdrawal of parasympathetic input to heart; hence, there was relatively over
sympathetic activity due to sympatho-vagal imbalance.
Keywords: Stress test, Sympatho-vagal imbalance, Autonomic function test.
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