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International Journal of Science and Research (IJSR)
ISSN (Online): 2319-7064
Index Copernicus Value (2013): 6
...
438

A Comprehensive Study of Autonomic Dysfunction
in Hypertension by Assessing Autonomic Function
Tests and HRV
Chiranjeevi Kumar Endukuru1, Sharan B
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Background: The pathophysiological
mechanism for the development of hypertension is the lack of balance between sympathetic and parasympathetic nervous system
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They
also forms an index of cardiac autonomic regulation
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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
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The subjects were selected based on exclusion-inclusion criteria
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05)
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05)
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Conclusion: From this study, it is evident that Hypertension can alter the normal
autonomic functions of the body and predisposes to autonomic neuropathy
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Keywords: Autonomic nervous system, Hypertension, Blood Pressure, Heart rate variability
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Introduction
Overall, approximately 20% of the world‟s adults are
estimated to have hypertension and contributing to more than
7
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Hypertension is defined as a
sustained elevation of systemic arterial blood pressure
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It can be produced secondary to many
diseases or more commonly without any cause
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The major
complications of hypertension are: Excess work load on the
heart leads to heart failure and coronary heart disease, often
leads to death due to heart attack, High pressure damages a
major blood vessels in brain, it is a cerebral infarct clinically
it is called stroke
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Hypertension is one of the common noncommunicable disease which is usually asymptomatic but
readily detectable and treatable condition and often leads to
lethal complications like coronary heart disease, stroke etc
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It is probably the most important public health
problem in all developed countries as they have achieved a
successful control of much infectious and communicable
disease
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If it becomes unbalanced, a person may experience
a variety of symptoms
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For these tests a person will be
attached to a blood pressure machine which monitors the
blood pressure continuously and an electrocardiograph which
monitors the heart rhythm continuously
...

The integrity of autonomic modulation of heart rate is
evaluated by analyzing heart rate variability (HRV) and
autonomic function testing
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2
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The approval of
Department of Cardiology and Medical ethics committee of
Narayana Medical College, Nellore was taken for this “A
Comprehensive Study of Autonomic Dysfunction in
Hypertension by Assessing Autonomic Function Tests and
HRV”
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The procedure was
explained and written consent was obtained from the
subjects
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The subject selection was
based on the predetermined exclusion-inclusion criteria
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The Autonomic function tests which were performed to
assess the cardiovascular sympathetic functional status:
1) Cold Pressor test (cold pressure test): Subject was
instructed regarding the test
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Cold water was taken in a
container
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Blood pressure was
recorded at the end of 60 seconds of submersion of the
limb
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2) Hand Grip Test: In the hand grip test, there is a rise in
heart rate and blood pressure
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Subject was
made to lie down in semi recumbent position
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Basal heart rate and blood pressure were recorded
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Heart rate and change in SBP, DBP were recorded
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Patient is
then asked to stand up and blood pressure is recorded at 0
and 1 minute intervals
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Subject was instructed to
maintain deep breathing at a rate of six breaths per minute
and was made to lie down comfortably in supine position
with head elevated to 300
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While subject was breathing
deeply at a rate of 6 breaths per minute (allowing 5
seconds each for inspiration and expiration) maximum and
minimum heart rates were recorded with each respiratory
cycle
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2) Valsalva Manoeuver - The valsalva ratio is a measure of
parasympathetic and sympathetic functions
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Nostrils were closed manually
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ECG machine was switched
on for continuous recording
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ECG changes were recorded throughout the
procedure, 30 seconds before and after the procedure
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3) Heart rate response to standing: On changing the
posture from supine to standing heart rate increases
immediately by 10-20 beats per minute
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Subject was made to lie down in supine posture
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Subject was asked to relax completely
for a minimum period of 10 minutes
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Subject was asked to
stand up immediately and change in heart rate is noted
from the monitoring screen of cardiowin
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Heart rate variability test: HRV was done between 9 am
to12 pm to minimize the effect of diurnal variation
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Subject was asked to lie down comfortably
on supine position for 5 minute before recording of HRV to
avoid wrong results
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The HRV was analyzed
both by the time domain and the frequency domain methods
during normal breathing by using PowerLab and LabChart
data acqusition software which Record, measure and analyze
beat-to-beat interval variation
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04 Hz)
LF - Low frequency spectrum (µs2) (Between 0
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15
Hz)
HF - High frequency spectrum (µs2)
(Between 0
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45 Hz)
LF/HF - LF/HF ratio

Table 2: Statistical analysis of sympathetic function tests in
Group I and Group II
Variables
Isometric Handgrip SBP
Isometric Handgrip DBP
Cold Pressor Test SBP
Cold Pressor Test DBP
BP Response to standing
SBP change
BP Response to standing
DBP change

Results were analyzed by SPSS version 17
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ANOVA and Student„t‟ test was used to compare the
data of hypertensive and normotensive subjects
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The P values < 0
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Data presented in Table 1 shows Age, anthropometric and
basal cardiovascular parameters of normotensive and
hypertensive subjects
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05) and the increase was statistically significant
(p<0
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Both the SBP and DBP reponses to standing are
also significantly higher in Hypertensives when compared to
normotensives (p<0
...


Hypertensives Normotensives P
(n=50)
(n=50)
value
HR response to standing 1
...
03
1
...
02 <0
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45±0
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65±0
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05*

75
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3

69
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0

SBP-159
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2
DBP-100
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2

SBP-124
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2
DBP-78
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2

<0
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842±0
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978±0
...
0001**
38
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4
56
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1
0
...
06±10
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90 ± 21
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0001**
17
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75
24
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16 0
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02±2
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15±3
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0001**

Table 5: Frequency Domain Analysis of HRV between
Hypertensives and Normotensives
Variables
TP (µs2)

Paper ID: SUB154936

1
...
20

Data presented in Table 5 shows that there was the frequency
domain indices of HRV in hypertensives and normotensives
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The decrease in frequency domain parameters
in hypertensives was found statistically significant (p
<0
...


Mean RR (s)
SDNN (ms)
RMSSD
NN50
PNN50 %

Heart rate (bpm)

1
...
16

Data presented in Table 4 shows that there was significant
decrease in time domain indices of HRV in hypertensives as
compared to normotensives
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9 1
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7 3
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0001)
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Variables

Blood Pressure(mm
of Hg)

<0
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0 4
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70 ± 9
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11±4
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9 3
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2±0
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47±4
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77±10
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13±4
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6 3
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9 ± 0
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05)
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05)
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05)
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Results

Age(yrs)
Height (cms)
Weight(kgs)
BMI (kg/m2 )

Hypertensives Normotensives P value
(n=50)
(n=50)
12
...
2
8
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3
<0
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1±1
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1±1
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05*
12
...
6
8
...
4
<0
...
1±1
...
1±1
...
05*
7
...
22
5
...
66 <0
...
6 138
...
4 364
...
0001**

Volume 4 Issue 5, May 2015
www
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Licensed Under Creative Commons Attribution CC BY

2853

International Journal of Science and Research (IJSR)
ISSN (Online): 2319-7064
Index Copernicus Value (2013): 6
...
438
VLF (µs2)
LF (µs2)
HF (µs2)
LF/HF ratio

832
...
8
222
...
6

79
...
2
29
...
6

1424
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9
1016
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7
511
...
5
303
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8

0
...
0001**
0
...
0002**

4
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This
decreased parasympathetic activity leads to decreased heart
rate variability with respiration, which is reflected in our
study as decreased E: I and Valsalva ratio values in
Hypertensives
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The results for the
above mentioned tests are statistically significant
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As a result venous return, cardiac output and arterial BP
decreases
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This in turn leads to
increased sympathetic discharge, decreased vagal tone and an
instantaneous increase in HR and BP
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This finding indicates possible dysfunction of
sympathetic and parasympathetic component of autonomic
nervous system
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al11
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The afferent fibers for this response are the pain fibers
which are stimulated by placing the hand in cold water and
the efferent fibers are the sympathetic fibers
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Hypertension impairs autonomic control of heart rate and
blood pressure
...
The pattern of rise of blood pressure was
within 30 seconds reaching its peak at around 60 seconds and
the basal blood pressure was achieved within 2 minutes in
normotensive subjects and prolonged pressor response was
found in hypertensive patients
...
Hypertensive subjects
respond to cold pressor stimulus with a predominant rise in
total peripheral resistance and also there were higher levels
of plasma norepinephrine
...
and
Douglas L
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al12, 13
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In hand grip test, increase in blood
pressure is due to increased sympathetic activity mediated by

Paper ID: SUB154936

the alpha adrenergic receptors of the autonomic nervous
system
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The results of the present investigation
have demonstrated that sustained handgrip causes significant
increase in arterial pressure in hypertensive patients
...
G
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al10
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This
reduction reflects the degree of cardiac autonomic activity
determined by the baroreceptor reflexes, which are impaired
in hypertensives
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Increased LF / HF ratio in hypertensives also indicating
sympathetic overdrive and sympathovagal balance
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The findings in our study correlated with the
previous studies 16, 17, 18, 19
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Acknowledgment
The authors are thankful to Dr
...
Phani Krishna, Department
of Cardiology for his help in sending the subjects
...
K
...
Maruthy for his contribution in the
concept
...

Conflict of Interest: Nil

6
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From present
study it indicates that hypertensives had markedly depressed
HRV and abnormal autonomic reflexes which reflects
sympathovagal imbalance
...


References
[1] William F Ganong, “Review of Medical Physiology”,
Twenty second edition; 2003
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volume
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Effects of cold pressor test on short – term
fluctuations of finger arterial blood pressure and heart
rate in normal subjects
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K
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[4] RG Victor, WN Lrimbach, “Effects of the cold pressor
test on muscle sympathetic nerve activity in humans
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[5] Harrison‟s principles of internal medicine vol-2
[6] Arthur Guyton
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K Mahajan, M
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Guptha “Text book of Social and
preventive medicine second edition
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[9] Knut severe et al, “Autonomic function in Hypertensive
and Normotensive subjects”, AHA journals; pg 13511356
...

[11] WW McCrory, AA Klein et
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“Sympathetic nervous
system and exercise tolerance response in normotensive
and hypertensive adolescents” J Am Coll Cardio
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1):381-6
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, Am J Hypertens 1991, 4, 627-629
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W
...
S
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[14] Pal GK, Pravati Pal “Spectral analysis of Heart Rate
Variability” Textbook of Practical Physiology 2010
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[15] Jagmeet P singh, Martin G Larson, Hisako Tsuji, Jane C
Evans, Christopher JO Donnell, Daniel Levy
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Hypertension 1998; 32: 293-297
...

[16] Virtanen R, Jula RA, Kuusela T, Helenius H, Voipio
Pulkki LM
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Journal of Human Hypertension 2003; 17:
171-179
...

[17] Xie Gui-Ling, Wang Jing-hua, Zhou Yan, Xu Hui, Sun
Jing-Hui, Yang Si-Rui
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Iran J
Paediatr 2013; 23: 37-44
...

[18] Mohd Urooj, Pillai KK, Monika Tandon, Venkateshan
SP, Nilanjan Saha
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Int J
Pharm PharmSci; 2011; 3(1): 36-39
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[19] Menezes JR, Oliveira LLM, Melo CSN, Freitas JR
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Progress in Biomedical research 2000; 1: 385388
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Autonomic nervous system dysregulation in
human hypertension
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1991; 67:3B–7B
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Components of heart rate
variability: what they really mean and what we really
measure
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1993; 72:821–822
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Sc
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Sc
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Currently working as a
Tutor/Demonstrator in the Department of physiology, AIIMS
Bhopal
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ijsr

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