Journal of Clinical and Diagnostic Research, ISSN - 0973 - 709X

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Dr Archana Dambal

"Journal of clinical and diagnostic research is a welcome change in publishing practices. It aims to reach out to the grass-root level researchers who do not lack in experience, clinical material and ideas, but lack in their knowledge in English language and statistics. The journal achieves it's aim by supporting in these exact domains.
It also gives due credit to all research designs like descriptive and qualitative studies while many journals ignore these important study designs. The rigorous review process does not allow any compromise in quality
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Dr. Archana Dambal
Department of General Medicine,
Belgaum Institute of Medical Sciences,Belgaum, Karnataka,INDIA,
On 30 Nov 2018




Dr Bhanu K Bhakhri

"The Journal of Clinical and Diagnostic Research (JCDR) has been in operation since almost a decade. It has contributed a huge number of peer reviewed articles, across a spectrum of medical disciplines, to the medical literature.
Its wide based indexing and open access publications attracts many authors as well as readers
For authors, the manuscripts can be uploaded online through an easily navigable portal, on other hand, reviewers appreciate the systematic handling of all manuscripts. The way JCDR has emerged as an effective medium for publishing wide array of observations in Indian context, I wish the editorial team success in their endeavour"



Dr Bhanu K Bhakhri
Faculty, Pediatric Medicine
Super Speciality Paediatric Hospital and Post Graduate Teaching Institute, Noida
On Sep 2018




Dr Mohan Z Mani

"Thank you very much for having published my article in record time.I would like to compliment you and your entire staff for your promptness, courtesy, and willingness to be customer friendly, which is quite unusual.I was given your reference by a colleague in pathology,and was able to directly phone your editorial office for clarifications.I would particularly like to thank the publication managers and the Assistant Editor who were following up my article. I would also like to thank you for adjusting the money I paid initially into payment for my modified article,and refunding the balance.
I wish all success to your journal and look forward to sending you any suitable similar article in future"



Dr Mohan Z Mani,
Professor & Head,
Department of Dematolgy,
Believers Church Medical College,
Thiruvalla, Kerala
On Sep 2018




Prof. Somashekhar Nimbalkar

"Over the last few years, we have published our research regularly in Journal of Clinical and Diagnostic Research. Having published in more than 20 high impact journals over the last five years including several high impact ones and reviewing articles for even more journals across my fields of interest, we value our published work in JCDR for their high standards in publishing scientific articles. The ease of submission, the rapid reviews in under a month, the high quality of their reviewers and keen attention to the final process of proofs and publication, ensure that there are no mistakes in the final article. We have been asked clarifications on several occasions and have been happy to provide them and it exemplifies the commitment to quality of the team at JCDR."



Prof. Somashekhar Nimbalkar
Head, Department of Pediatrics, Pramukhswami Medical College, Karamsad
Chairman, Research Group, Charutar Arogya Mandal, Karamsad
National Joint Coordinator - Advanced IAP NNF NRP Program
Ex-Member, Governing Body, National Neonatology Forum, New Delhi
Ex-President - National Neonatology Forum Gujarat State Chapter
Department of Pediatrics, Pramukhswami Medical College, Karamsad, Anand, Gujarat.
On Sep 2018




Dr. Kalyani R

"Journal of Clinical and Diagnostic Research is at present a well-known Indian originated scientific journal which started with a humble beginning. I have been associated with this journal since many years. I appreciate the Editor, Dr. Hemant Jain, for his constant effort in bringing up this journal to the present status right from the scratch. The journal is multidisciplinary. It encourages in publishing the scientific articles from postgraduates and also the beginners who start their career. At the same time the journal also caters for the high quality articles from specialty and super-specialty researchers. Hence it provides a platform for the scientist and researchers to publish. The other aspect of it is, the readers get the information regarding the most recent developments in science which can be used for teaching, research, treating patients and to some extent take preventive measures against certain diseases. The journal is contributing immensely to the society at national and international level."



Dr Kalyani R
Professor and Head
Department of Pathology
Sri Devaraj Urs Medical College
Sri Devaraj Urs Academy of Higher Education and Research , Kolar, Karnataka
On Sep 2018




Dr. Saumya Navit

"As a peer-reviewed journal, the Journal of Clinical and Diagnostic Research provides an opportunity to researchers, scientists and budding professionals to explore the developments in the field of medicine and dentistry and their varied specialities, thus extending our view on biological diversities of living species in relation to medicine.
‘Knowledge is treasure of a wise man.’ The free access of this journal provides an immense scope of learning for the both the old and the young in field of medicine and dentistry as well. The multidisciplinary nature of the journal makes it a better platform to absorb all that is being researched and developed. The publication process is systematic and professional. Online submission, publication and peer reviewing makes it a user-friendly journal.
As an experienced dentist and an academician, I proudly recommend this journal to the dental fraternity as a good quality open access platform for rapid communication of their cutting-edge research progress and discovery.
I wish JCDR a great success and I hope that journal will soar higher with the passing time."



Dr Saumya Navit
Professor and Head
Department of Pediatric Dentistry
Saraswati Dental College
Lucknow
On Sep 2018




Dr. Arunava Biswas

"My sincere attachment with JCDR as an author as well as reviewer is a learning experience . Their systematic approach in publication of article in various categories is really praiseworthy.
Their prompt and timely response to review's query and the manner in which they have set the reviewing process helps in extracting the best possible scientific writings for publication.
It's a honour and pride to be a part of the JCDR team. My very best wishes to JCDR and hope it will sparkle up above the sky as a high indexed journal in near future."



Dr. Arunava Biswas
MD, DM (Clinical Pharmacology)
Assistant Professor
Department of Pharmacology
Calcutta National Medical College & Hospital , Kolkata




Dr. C.S. Ramesh Babu
" Journal of Clinical and Diagnostic Research (JCDR) is a multi-specialty medical and dental journal publishing high quality research articles in almost all branches of medicine. The quality of printing of figures and tables is excellent and comparable to any International journal. An added advantage is nominal publication charges and monthly issue of the journal and more chances of an article being accepted for publication. Moreover being a multi-specialty journal an article concerning a particular specialty has a wider reach of readers of other related specialties also. As an author and reviewer for several years I find this Journal most suitable and highly recommend this Journal."
Best regards,
C.S. Ramesh Babu,
Associate Professor of Anatomy,
Muzaffarnagar Medical College,
Muzaffarnagar.
On Aug 2018




Dr. Arundhathi. S
"Journal of Clinical and Diagnostic Research (JCDR) is a reputed peer reviewed journal and is constantly involved in publishing high quality research articles related to medicine. Its been a great pleasure to be associated with this esteemed journal as a reviewer and as an author for a couple of years. The editorial board consists of many dedicated and reputed experts as its members and they are doing an appreciable work in guiding budding researchers. JCDR is doing a commendable job in scientific research by promoting excellent quality research & review articles and case reports & series. The reviewers provide appropriate suggestions that improve the quality of articles. I strongly recommend my fraternity to encourage JCDR by contributing their valuable research work in this widely accepted, user friendly journal. I hope my collaboration with JCDR will continue for a long time".



Dr. Arundhathi. S
MBBS, MD (Pathology),
Sanjay Gandhi institute of trauma and orthopedics,
Bengaluru.
On Aug 2018




Dr. Mamta Gupta,
"It gives me great pleasure to be associated with JCDR, since last 2-3 years. Since then I have authored, co-authored and reviewed about 25 articles in JCDR. I thank JCDR for giving me an opportunity to improve my own skills as an author and a reviewer.
It 's a multispecialty journal, publishing high quality articles. It gives a platform to the authors to publish their research work which can be available for everyone across the globe to read. The best thing about JCDR is that the full articles of all medical specialties are available as pdf/html for reading free of cost or without institutional subscription, which is not there for other journals. For those who have problem in writing manuscript or do statistical work, JCDR comes for their rescue.
The journal has a monthly publication and the articles are published quite fast. In time compared to other journals. The on-line first publication is also a great advantage and facility to review one's own articles before going to print. The response to any query and permission if required, is quite fast; this is quite commendable. I have a very good experience about seeking quick permission for quoting a photograph (Fig.) from a JCDR article for my chapter authored in an E book. I never thought it would be so easy. No hassles.
Reviewing articles is no less a pain staking process and requires in depth perception, knowledge about the topic for review. It requires time and concentration, yet I enjoy doing it. The JCDR website especially for the reviewers is quite user friendly. My suggestions for improving the journal is, more strict review process, so that only high quality articles are published. I find a a good number of articles in Obst. Gynae, hence, a new journal for this specialty titled JCDR-OG can be started. May be a bimonthly or quarterly publication to begin with. Only selected articles should find a place in it.
An yearly reward for the best article authored can also incentivize the authors. Though the process of finding the best article will be not be very easy. I do not know how reviewing process can be improved. If an article is being reviewed by two reviewers, then opinion of one can be communicated to the other or the final opinion of the editor can be communicated to the reviewer if requested for. This will help one’s reviewing skills.
My best wishes to Dr. Hemant Jain and all the editorial staff of JCDR for their untiring efforts to bring out this journal. I strongly recommend medical fraternity to publish their valuable research work in this esteemed journal, JCDR".



Dr. Mamta Gupta
Consultant
(Ex HOD Obs &Gynae, Hindu Rao Hospital and associated NDMC Medical College, Delhi)
Aug 2018




Dr. Rajendra Kumar Ghritlaharey

"I wish to thank Dr. Hemant Jain, Editor-in-Chief Journal of Clinical and Diagnostic Research (JCDR), for asking me to write up few words.
Writing is the representation of language in a textual medium i e; into the words and sentences on paper. Quality medical manuscript writing in particular, demands not only a high-quality research, but also requires accurate and concise communication of findings and conclusions, with adherence to particular journal guidelines. In medical field whether working in teaching, private, or in corporate institution, everyone wants to excel in his / her own field and get recognised by making manuscripts publication.


Authors are the souls of any journal, and deserve much respect. To publish a journal manuscripts are needed from authors. Authors have a great responsibility for producing facts of their work in terms of number and results truthfully and an individual honesty is expected from authors in this regards. Both ways its true "No authors-No manuscripts-No journals" and "No journals–No manuscripts–No authors". Reviewing a manuscript is also a very responsible and important task of any peer-reviewed journal and to be taken seriously. It needs knowledge on the subject, sincerity, honesty and determination. Although the process of reviewing a manuscript is a time consuming task butit is expected to give one's best remarks within the time frame of the journal.
Salient features of the JCDR: It is a biomedical, multidisciplinary (including all medical and dental specialities), e-journal, with wide scope and extensive author support. At the same time, a free text of manuscript is available in HTML and PDF format. There is fast growing authorship and readership with JCDR as this can be judged by the number of articles published in it i e; in Feb 2007 of its first issue, it contained 5 articles only, and now in its recent volume published in April 2011, it contained 67 manuscripts. This e-journal is fulfilling the commitments and objectives sincerely, (as stated by Editor-in-chief in his preface to first edition) i e; to encourage physicians through the internet, especially from the developing countries who witness a spectrum of disease and acquire a wealth of knowledge to publish their experiences to benefit the medical community in patients care. I also feel that many of us have work of substance, newer ideas, adequate clinical materials but poor in medical writing and hesitation to submit the work and need help. JCDR provides authors help in this regards.
Timely publication of journal: Publication of manuscripts and bringing out the issue in time is one of the positive aspects of JCDR and is possible with strong support team in terms of peer reviewers, proof reading, language check, computer operators, etc. This is one of the great reasons for authors to submit their work with JCDR. Another best part of JCDR is "Online first Publications" facilities available for the authors. This facility not only provides the prompt publications of the manuscripts but at the same time also early availability of the manuscripts for the readers.
Indexation and online availability: Indexation transforms the journal in some sense from its local ownership to the worldwide professional community and to the public.JCDR is indexed with Embase & EMbiology, Google Scholar, Index Copernicus, Chemical Abstracts Service, Journal seek Database, Indian Science Abstracts, to name few of them. Manuscriptspublished in JCDR are available on major search engines ie; google, yahoo, msn.
In the era of fast growing newer technologies, and in computer and internet friendly environment the manuscripts preparation, submission, review, revision, etc and all can be done and checked with a click from all corer of the world, at any time. Of course there is always a scope for improvement in every field and none is perfect. To progress, one needs to identify the areas of one's weakness and to strengthen them.
It is well said that "happy beginning is half done" and it fits perfectly with JCDR. It has grown considerably and I feel it has already grown up from its infancy to adolescence, achieving the status of standard online e-journal form Indian continent since its inception in Feb 2007. This had been made possible due to the efforts and the hard work put in it. The way the JCDR is improving with every new volume, with good quality original manuscripts, makes it a quality journal for readers. I must thank and congratulate Dr Hemant Jain, Editor-in-Chief JCDR and his team for their sincere efforts, dedication, and determination for making JCDR a fast growing journal.
Every one of us: authors, reviewers, editors, and publisher are responsible for enhancing the stature of the journal. I wish for a great success for JCDR."



Thanking you
With sincere regards
Dr. Rajendra Kumar Ghritlaharey, M.S., M. Ch., FAIS
Associate Professor,
Department of Paediatric Surgery, Gandhi Medical College & Associated
Kamla Nehru & Hamidia Hospitals Bhopal, Madhya Pradesh 462 001 (India)
E-mail: drrajendrak1@rediffmail.com
On May 11,2011




Dr. Shankar P.R.

"On looking back through my Gmail archives after being requested by the journal to write a short editorial about my experiences of publishing with the Journal of Clinical and Diagnostic Research (JCDR), I came across an e-mail from Dr. Hemant Jain, Editor, in March 2007, which introduced the new electronic journal. The main features of the journal which were outlined in the e-mail were extensive author support, cash rewards, the peer review process, and other salient features of the journal.
Over a span of over four years, we (I and my colleagues) have published around 25 articles in the journal. In this editorial, I plan to briefly discuss my experiences of publishing with JCDR and the strengths of the journal and to finally address the areas for improvement.
My experiences of publishing with JCDR: Overall, my experiences of publishing withJCDR have been positive. The best point about the journal is that it responds to queries from the author. This may seem to be simple and not too much to ask for, but unfortunately, many journals in the subcontinent and from many developing countries do not respond or they respond with a long delay to the queries from the authors 1. The reasons could be many, including lack of optimal secretarial and other support. Another problem with many journals is the slowness of the review process. Editorial processing and peer review can take anywhere between a year to two years with some journals. Also, some journals do not keep the contributors informed about the progress of the review process. Due to the long review process, the articles can lose their relevance and topicality. A major benefit with JCDR is the timeliness and promptness of its response. In Dr Jain's e-mail which was sent to me in 2007, before the introduction of the Pre-publishing system, he had stated that he had received my submission and that he would get back to me within seven days and he did!
Most of the manuscripts are published within 3 to 4 months of their submission if they are found to be suitable after the review process. JCDR is published bimonthly and the accepted articles were usually published in the next issue. Recently, due to the increased volume of the submissions, the review process has become slower and it ?? Section can take from 4 to 6 months for the articles to be reviewed. The journal has an extensive author support system and it has recently introduced a paid expedited review process. The journal also mentions the average time for processing the manuscript under different submission systems - regular submission and expedited review.
Strengths of the journal: The journal has an online first facility in which the accepted manuscripts may be published on the website before being included in a regular issue of the journal. This cuts down the time between their acceptance and the publication. The journal is indexed in many databases, though not in PubMed. The editorial board should now take steps to index the journal in PubMed. The journal has a system of notifying readers through e-mail when a new issue is released. Also, the articles are available in both the HTML and the PDF formats. I especially like the new and colorful page format of the journal. Also, the access statistics of the articles are available. The prepublication and the manuscript tracking system are also helpful for the authors.
Areas for improvement: In certain cases, I felt that the peer review process of the manuscripts was not up to international standards and that it should be strengthened. Also, the number of manuscripts in an issue is high and it may be difficult for readers to go through all of them. The journal can consider tightening of the peer review process and increasing the quality standards for the acceptance of the manuscripts. I faced occasional problems with the online manuscript submission (Pre-publishing) system, which have to be addressed.
Overall, the publishing process with JCDR has been smooth, quick and relatively hassle free and I can recommend other authors to consider the journal as an outlet for their work."



Dr. P. Ravi Shankar
KIST Medical College, P.O. Box 14142, Kathmandu, Nepal.
E-mail: ravi.dr.shankar@gmail.com
On April 2011

Important Notice

Original article / research
Year : 2011 | Month : December | Volume : 5 | Issue : 8 | Page : 1537 - 1541

Mental Stress Induced Changes in Autonomic Nervous Activity in Normotensive ffsprings of Hypertensive Parents

Jnaneshwara P. Shenoy, Shivakumar J., Kanmani T.L., Shailaja Moodithaya, Amrit Mirajkar, Preethi Ganapathi Pai

1. Associate Professor, Department of Physiology, Father Muller Medical College, Mangalore 2. Assistant Professor, Department of Physiology, KIMS, Hubli 3. Final year MBBS Student K S Hegde Medical Academy, Mangalore 4. Asso. Prof Department of Physiology, K S Hedge Medical Academy, Mangalore. 5. Prof & Head Department of Physiology, K S Hedge Medical Academy, Mangalore. 6. Asso. Prof, Department of Pharmacology, Kasturba Medical College, Mangalore, Manipal University

Correspondence Address :
Jnaneshwar Shenoy
Associate Professor, Department of Physiology,
Father Muller Medical College, Mangalore – 575002
Phone: +91 9886732843
E-mail: drjnani@yahoo.co.in

Abstract

Back ground: The genetic component is a major contributor in the pathogenesis of essential hypertension. Consequently the likelihood of acquiring hypertension in offspring of hypertensive parents has been estimated to be higher when compared to that of normotensive individuals. The current study is an attempt to identify the early markers for the development of hypertension in these individuals by assessing the autonomic nervous activity when subjected to mental stress.

Methodology: Two groups of thirty normotensive subjects matched for age, body mass index, and physical activity were recruited .The only differentiating factor between the two groups being the genetic predisposition to hypertension of one group. Blood pressure & electrocardiogram was recorded in both groups at rest and during mental stress. Power spectral analysis of heart rate variability was done.Statistical analyses were conducted by paired & unpaired t-test. A p value of < 0.05 was considered as statistically significant.

Results: A significant decrease in high frequency normalized (HFnu) in the offspring of hypertensive parents was observed at rest. During mental stress, an increase in heart rate, systolic and diastolic blood pressure was observed in both groups. Increase in low frequency normalized and decrease in HFnu in offsprings of normotensive parents and increase in LF/HF ratio in individual with hypertensive parents were observed. Difference in basal and mental stress value of heart rate and systolic pressure was significantly more and HFnu was less in offspring of hypertensives.

Conclusion: Impairment in parasympathetic activity at rest and sympathovagal imbalance during mental stress is observed in individuals with hypertensive parents. This implies high chances of developing hypertension in their later life. So an evaluation of autonomic nervous activity by simple procedures like heart rate variability analysis to all individuals with a family history of hypertension in early stages of their life would prove to be invaluable. Life style modification such as regular exercises, yoga etc. can be suggested to those individuals who are found to be at the risk of developing hypertension.

Keywords

Mental stress, Hypertension, Heart rate variability parasympathetic

How to cite this article :

Jnaneshwara P. Shenoy, Shivakumar J., Kanmani T.L., Shailaja Moodithaya, Amrit Mirajkar, Preethi Ganapathi Pai. MENTAL STRESS INDUCED CHANGES IN AUTONOMIC NERVOUS ACTIVITY IN NORMOTENSIVE FFSPRINGS OF HYPERTENSIVE PARENTS. Journal of Clinical and Diagnostic Research [serial online] 2011 December [cited: 2019 Jul 21 ]; 5:1537-1541. Available from
http://jcdr.net/back_issues.asp?issn=0973-709x&year=2011&month=December&volume=5&issue=8&page=1537-1541&id=1784

INTRODUCTION
Hypertension is one of the major risk factors for coronary artery diseases, congestive heart failure, stroke, peripheral vascular disease, kidney failure and retinopathy. Essential hypertension is characterized by an increase in sympathetic nervous system activity, reduced vagal modulations of the sinoatrial node and blunted baroreflex gain. Since incidence of genetic component of essential hypertension is as high as 60%, normotensive offspring of one essential hypertensive parent are at increased likelihood to develop essential hypertension (1), (2).

Although the pathogenesis of essential hypertension is unclear, dysregulation of the autonomic nervous system with evidence of sympathetic hyperactivity and/or vagal withdrawal has been implicated in its development. Heart rate variability (HRV) has emerged as a practical, non-invasive tool to quantitatively investigate cardiac autonomic dysregulation in hypertension. Studies havereported a decreased HRV among hypertensive patients and that the relation between blood pressure and HRV is present across a wide range of blood pressure (3), (4).

HRV is an important indicator of both physiological resiliency and behavioral flexibility, reflecting the individual’s capacity to adapt effectively to stress and environmental demands. It has become apparent that while a large degree of instability is detrimental to efficient physiological functioning, too little variation can also be pathological. An optimal level of variability within an organism is a key regulatory system which is critical to the inherent flexibility and adaptability that epitomize healthy function.

Various previous studies have shown that mental stress increases sympathetic activity and decreases parasympathetic activity (5), (6), (7). This results in increased strain on the heart, immune and hormonal systems. Acute period of mental stress can also results in reduced HRV. This phenomenon suggests a mechanism through which psychological stress may exacerbate cardiac rhythm disturbances (8).

One of the most active areas in psychosomatic research has focused on cardiovascular reactivity to mental stress. The underlying assumption of this study is that excessive cardiovascular responses of stress plays a key role in the development of hypertension. The necessity of this study is further strengthened by the lack of extensive literature on the effect of mental stress on autonomic nervous activity in normotensive offspring of normotensive and hypertensive parents. Hence the present study is designed to evaluate the effect of mental stress on autonomic nervous activity between healthy normotensive offspring of normotensive parents as compared to that of hypertensive parents.

Material and Methods

A total of 60 healthy normotensive subjects aged between 18-25 years with a normal BMI and leading a sedentary life style were considered. Thirty subjects, having at least one hypertensive parent constituted the study group. The control group consisted of thirty age and sex matched individuals with normotensive parents. All the subjects were recruited from KS.Hegde Medical Academy campus at Deralakatte, Mangalore after a thorough clinical examination. Informed written consent was obtained from all the participants, and the experiment protocol was approved by the Institutional Ethics committee. Athletes, those who practice yoga or exercises, those with history of cardiovascular, respiratory, psychiatric diseases and consumption of alcohol and tobacco or any medications that affect the autonomic nervous activity were excluded. There were no dropouts in either the subject or control group that were recruited.

All the participants reported for the study, after refraining from food for at least 2 hours. They were also instructed not to consume caffeinated or cocoa containing beverages 12 hours prior to recording. Height was measured to the nearest 0.1cm without footwear using vertically movable scale. Weight was measured to the nearest 100 grams using a digital scale and BMI was calculated.

Prior to recording of the electrocardiogram (ECG), the subjects were required to take rest for a period of 15 minutes. A basal recording of blood pressure was taken using a mercury sphygmomanometer, with the subject in supine position. 3M standard chest electrodes (Ag- AgCl) were used and electrodes were placed on the right upper limb and both the lower limbs. A basal ECG recording for 5 minutes was taken with the subject in the supine position.

Mental stress test was performed using standard serial subtraction test (9). A serial subtraction mathematical task was chosen as the stressor in this study because mental math was easy to administer and offers infinite variations and less ethical problems than other active stressors. ECG was recorded for a period of 5 minutes from the time he/she started the serial subtraction task (i.e. onset of mental stress). Immediately blood pressure was recorded in the same position.

It was ensured that the subjects were awake, supine and breathing normally, and they were asked to avoid unnecessary movements during this entire period.

HRV Analysis: A noise- free ECG was obtained with the sampling frequency of 1024 Hz. Spectral analysis was performed off-line using POWERLABS-(Version 7.0). Data was edited manually for artifacts. HRV software used a peak detection alogrithm to find the ‘R’ wave. The detection was done at a re-sampling rate of 4 Hz. Each detected ‘R’ wave was considered as a data point. A minimum of 256 data points are required to perform a spectral analysis, for which a minimum duration of 5 minutes of ECG recording was required.

Spectral analysis was performed using a Fast Fourier Transformation (FFT). The power was calculated in two bands: the 0.15-0.4 Hz band of RR power considered as high frequency (HF) reflects parasympathetic nerve activity to the heart, while 0.04-0.15 Hz considered as low frequency band (LF) was believed to reflect at least in part, sympathetic nervous activity to the heart. In addition to absolute power, the data was also presented as normalized units (HFnu & LFnu). The ratio of low frequency to high frequency (LF/ HF) represents a measure of the balance of sympathetic and parasympathetic function (10), (11).

Statistical Analysis: Total study population of sixty comprised of two independent groups containing thirty subjects each. Data was analyzed using independent t -test for comparison of HRV parameters, heart rate and blood pressure between the two groups. Paired t-test was used for comparison of same parameters obtained during rest and mental stress within the same group. Effect of mental stress was analyzed by comparing the differences between values recorded at rest and during mental stress between control and study group using unpaired t- test.

Results

The anthropometric data showed no significant difference between the offspring of normotensive and hypertensive parents as depicted in (Table/Fig 1).

There was no significant difference between the control and the study group with respect to heart rate, systolic and diastolic blood pressures when measured at rest (Table/Fig 2). However, high frequency normalized (HFnu), was significantly, lower in study group (p<0.001) (Table/Fig 3).

During mental stress both study as well as control group exhibited significant increase in heart rate, systolic and diastolic blood pressures (Table/Fig 2). A significant increase in Lfnu and a decrease in HFnu were observed in the control group when compared to their basal values. There was a similar significant increase in LF/HF ratio in the study group when compared to its basal value (Table/Fig 4).

On comparing the mean values of the difference in various parameters, (heart rate, systolic and diastolic blood pressure and HRV).

at rest and during mental stress, the change in heart rate and systolic blood pressure was found to be more in the study group (Table/Fig 2) Among the changes observed in HRV parameters as shown in the (Table/Fig 4) only difference in Hfnu was found to be significantly less in the study group (p<0.05).

Discussion

The rhythmic beating of the heart at rest is believed to be monotonously regular; it is now known that the rhythm of a healthy heart under resting conditions is actually surprisingly irregular. These moment-to-moment variations in heart rate was easily overlooked when average heart rate is calculated. HRV derived from the ECG is a measurement of these naturally occurring, beatto- beat variations in heart rate.

This non-invasive, detailed and sophisticated analysis of fluctuations in heart rate can be used to indirectly assess the autonomic control of heart. Changes in the HRV pattern provides an early and sensitive indicator of compromised health. A high variability in heart rate is a sign of good adaptability, implying a healthy individual with a well functioning autonomic control mechanism. Conversely, lower variability is often an indicator of abnormal and insufficient adaptability of the autonomic nervous system implying the presence of a physiological malfunction.

The present study is an attempt to assess and compare the autonomic nervous activity by analysis of HRV at rest and during mental stress on young normotensive offspring of normotensive and hypertensive parents divided in two separate groups. Since factors like age, obesity and physical activity can influence the HRV, we included only those individuals that match for these factors. On statistical analysis of the anthropometric data (Table/Fig 1) no significant difference was noted in age, height, weight and BMI.

An analysis of the HRV data obtained at resting state in both the groups (Table/Fig 1) revealed that there was a significant reduction in HFnu of the offspring of hypertensive parents. Similar findings were also observed by Soumya et al (12), Maver et al (13) and Wu J S et al (14). HFnu was considered as an index of modulation of parasympathetic branch of autonomic nervous system (ANS) as it influenced the sinoatrial node. This was suggestive of an early onset of impairment of parasympathetic activity of autonomic nervous system at cardiac level in offspring of hypertensive individuals.

A significant increase in LFnu, average heart rate, systolic and diastolic blood pressure and a decrease in HFnu were observed in offspring of normotensive parents (Table/Fig 1) and (Table/Fig 4). The studyconducted by Andrei et al (15) reported an increase in heart rate, mean arterial pressure and LFnu with a decrease in HFnu, when individuals were subjected to mental stress. LFnu is viewed as an indicator of aggregate modulation of both sympathetic & parasympathetic branches of ANS. Devrath et al (1) in a previous study have shown that an increase in LF & decrease in HF is suggestive of an overall increase in sympathetic activity leading to an increase in average heart rate and BP during mental stress in offspring of normotensive parents.

However, those with hypertensive parents showed a significant increase in LF/HF ratio, average heart rate, systolic and diastolic blood pressure (Table/Fig 4). LF/HF ratio is a widely used HRV index of sympothovagal balance between the two branches of autonomic nervous system. Dayanand G et al (16), found an increase in heart rate, systolic and diastolic blood pressure similar to the present study but they noticed these findings during physical stress in offspring of hypertensives and suggested that in young normotensive subjects, parental hypertension was associated with stiffening of carotid artery and reduction in cardiovagal outflow and baroreflex gain. This dysregulation in autonomic nervous system can explain an increase in heart rate, systolic and diastolic blood pressure.

In the present study the difference in HFnu which was significantly less in offspring of hypertensive subjects when compared with the basal value was suggestive of reduced modulation of parasympathetic activity. It was also noted that the differences between basal and mental stress values of heart rate and systolic pressure were significantly higher, in those who had positive family history of hypertension. This may be due to a hyperactive sympathetic nervous system which may lead to further consequences like peripheral vasoconstriction, an increase in heart rate, resulting in increase in peripheral vascular resistance with rise in systemic blood pressure(17). In support of this, Falkner B et al(18), noticed a rise in plasma catecholamine levels in association with increased sympathetic activity in individuals with genetic predisposition to hypertension. Noll G et al(19), in a similar study found that the activity of the sympathetic nervous system and plasma norepinephrine and endothelin levels are increased during mental stress in offspring of hypertensive parents. Endothelin was a locally released vascular regulator that at very low concentrations enhances constriction in the presence of norepinephrine and at higher concentrations had potent direct vasoconstrictor properties. These early functional changes of central and local cardiovascular regulation may be important in the pathogenesis of essential hypertension.

The fact that the offspring of hypertensive parents were still normotensive indicates that the observed changes in cardiovascular responsiveness occur at an early stage, are probably of genetic origin, and could play a role in the pathogenesis of hypertension. Evidence of reduced parasympathetic modulation and elevated sympathetic activation at such an early stage of life in offspring of hypertensives suggest the necessity of targeting reduction in sympathetic activation as a primary goal in prevention of hypertension. This could be achieved by early identification of individual with ‘pre-hypertensive’ state and by implementing preventive measures like regular exercises change in food habits and life style modification such as Yoga.

Conclusion

HRV analysis brings to fore the subtle yet critically important changes in autonomic activity occurring during the normal beating of theheart. Analysis of these changes provides an important insight into the autonomic nervous system. This tool was therefore employed to scout for autonomic nervous system perturbations in normotensive individuals with a genetic susceptibility for hypertension. This study found that in these subjects there was a reduced modulation of para-sympathetic activity and a hyperactive sympathetic nervous system when subjected to mental stress. Since these subjects were essentially normotensive at rest, therefore these two features may constitute a “pre-hypertensive “state. Such findings in a young normotensive individual may serve as a “red flag” for future development of hypertension and thereby help them in adopting changes in diet and lifestyle in order to thwart the development of hypertension. Some of the limitations of our study which if covered by future studies would throw more light on the effect of stressors to uncover the “dormant” hypertension in genetically susceptible individuals are as follows. In our study we were not able to evaluate the beat-to-beat variations in BP and this could probably have provided a more complete picture about the autonomic control of entire cardiovascular system. Further our study included only offspring’s of parents wherein only one parent was hypertensive, whether having both parents who are hypertensive further adds to the changes observed has to be studied. Finally whether addition of other stressors accentuates the observed changes also needs to be evaluated.

Key Message

The two groups involved in the study are matched for age, BMI, and physical activity. The important factor that differs in both groups is the genetic predisposition of hypertension in the group containing offsprings of hypertensive parents. An impairment in parasympathetic activity in young offspring of hypertensives even at rest is found. Sympothovagal imbalance during mental stress is observed in individuals with hypertensive parents. This implies high chances of developing hypertension in their later life. An evaluation of autonomic nervous activity by simple non-invasive procedures like HRV analysis to all individuals with the family history of hypertension in early stages of their life can reveal the future risk of development of hypertension Life style modification such as regular exercises, Yoga etc. can be suggested to those individuals who are found to be at risk of developing hypertension.

Acknowledgement

Part of this study was funded by ICMR. We would like to acknowledge and convey our gratitude to ICMR.

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