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

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Dr Mohan Z Mani

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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."



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




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"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
Anuradha

Dear team JCDR, I would like to thank you for the very professional and polite service provided by everyone at JCDR. While i have been in the field of writing and editing for sometime, this has been my first attempt in publishing a scientific paper.Thank you for hand-holding me through the process.


Dr. Anuradha
E-mail: anuradha2nittur@gmail.com
On Jan 2020

Important Notice

Original article / research
Year : 2021 | Month : September | Volume : 15 | Issue : 9 | Page : CC10 - CC14 Full Version

Influence of Stress on Quality of Sleep and QT Interval Variables among Young Adult Medical Students- A Cross-sectional Study


Published: September 1, 2021 | DOI: https://doi.org/10.7860/JCDR/2021/50023.15386
Afreen Begum H Itagi, Amudharaj Dharmalingam, Satish Dipankar, Akshay Berad, Senthil M Velou, Senthil Kumar Subramanian

1. Assistant Professor, Department of Physiology, All India Institute of Medical Sciences, Mangalagiri, Andhra Pradesh, India. 2. Associate Professor, Department of Physiology, All India Institute of Medical Sciences, Mangalagiri, Andhra Pradesh, India. 3. Associate Professor, Department of Physiology, All India Institute of Medical Sciences, Patna, Bihar, India. 4. Assistant Professor, Department of Physiology, Government Medical College, Nagpur, Maharashtra, India. 5. Assistant Professor, Department of Physiology, All India Institute of Medical Sciences, Mangalagiri, Andhra Pradesh, India. 6. Assistant Professor, Department of Physiology, All India Institute of Medical Sciences, Mangalagiri, Andhra Pradesh, India.

Correspondence Address :
Dr. Afreen Begum H Itagi,
All India Institute of Medical Sciences, Mangalagiri, Andhra Pradesh, India.
E-mail: afreen.itagi@gmail.com

Abstract

Introduction: Stress affects different cardiovascular responses and trigger arrhythmias through Autonomic Nervous System (ANS) activation. Medical students generally tend to reduce their sleep, in order to adjust and cope with their stressful and demanding workload.

Aim: To assess the correlation of QT intervals variables with quality of sleep and stress among young adult medical students.

Materials and Methods: This cross-sectional study was undertaken in All India Institute of Medical Sciences, Mangalagiri, Andhra Pradesh, India, among 60 medical students taken as internal match for collection of data at the beginning of the academic year (unstressed) and three weeks before the term-end examination (stressed) during October 2019 to March 2020. Two validated questionnaires namely, Pittsburgh Sleep Quality Index (PSQI) to assess sleep quality and the Medical Student Stress Questionnaire (MSSQ) to measure the stressors and the intensity of stress were used among the medical students. Short-term Electrocardiogram (ECG) recording was used to measure QT interval variables. Descriptive statistics and paired t-test were applied using Statistical Package for the Social Sciences (SPSS) version 19.0. The p≤0.05 was considered significant.

Results: Academic Related Stress (ARS) showed a highly significant increase during the stressed conditions (p<0.001). The mean global PSQI score of 6.03±2.76 was significantly higher (p-value <0.001; PSQI >5) during the stressed conditions indicating poor quality of sleep, when compared to 4.50±2.87 recorded in unstressed conditions. In stressed conditions, QT interval measures had moderate correlation with ARS. Quality of sleep had negative correlations with all QT interval measures except for corrected QT interval (QTc) and QTCmin.

Conclusion: Stress affects the sleep quality and induced QT changes which reflected difference in variability between ‘stressed’ and ‘unstressed’ times. However, there is no significant impact on QT duration among the young adult medical students.

Keywords

Academic stress, Education, Electrocardiogram, QT variability, Undergraduate

Sleep is an inherent and essential physiological phenomenon that contributes to the health and well-being of an individual. The American Academy of Sleep Medicine and the Sleep Science Society in their recent consensus statement had stated that to attain a good and healthy life, every individual on daily basis should acquire a minimum of seven or more hours of sleep every night. The consensus statement also throws light on the adverse outcomes of sleep deprivation and states that sleep of less the seven hours every night might result in depression, impaired performance, increases chances of error or accidents, and even jeopardises human life by impairing bodily immune functions (1),(2).

Stress is characterised as the non specific reaction or response of the body to demands made on it or because of environmental events that are too disturbing. It is not just a stimulus or a rational response, but it is a manner in which we perceive and comply with threats and challenges to the environment (3),(4). Stress that can stimulate and encourage learning is called favourable stress, whereas unfavourable stress can hinder and suppress learning. Various studies have revealed that unfavourable stress levels shown to have a potential correlation with higher anxiety and depression levels of medical students, difficulties in solving interpersonal disputes, increased intake of alcohol and other drugs coupled with sleeping disorders (5),(6),(7),(8).

Many times it has been observed that medical students prefer to minimise their sleep in an attempt to adapt and cope with their workload and stressful environment (9). Little has been published about pre clinical medical students’ sleep habits, a potentially modifiable factor in student wellness. Unlike resident physicians or medical students in clerkships, pre clinical medical students’ sleep is not yet determined by call schedules or patient care workload. However, the enormous volume of information they must master places high demands on the students’ time, leaving relatively little time for rest. High aspirations may cause students to sacrifice sleep for better grades. These pre clinical years would ideally set the foundation for time management and self-care in the future (4),(5). Unfortunately, by the end of the first year of medical school, many students already report changes in health habits such as decreased sleep, decreased exercise, and an increase in substance abuse (7),(8).

A stressor is defined as a personal or environmental event that causes stress. Medical student stressors can usually be split into six types: stressors related to academics, those related to teaching and learning, those related to intrapersonal and interpersonal reasons, those related to social-related, those related to drive and desire, and ultimately those related to group activities (10),(11).

Stress influences multiple cardiovascular responses and the stress-induced activation of the ANS might also trigger fatal arrhythmias by altering neural transmissions to the heart (12),(13). Epidemiologic evidence suggests that there is a relationship between stress and cardiac morbidity and mortality in susceptible individuals. The QT interval represents the time between the onset of electrical stimulation and its recovery and is called the duration of repolarisation (14),(15),(16),(17). Several variables such as genetic, physiological, patho-physiological, etc., influence the QT interval in a person, whereas the earlier published studies provide conflicting evidence on the effects of mental stress on the QT interval and dispersion (18),(19),(20). It has been observed that QT interval is prolonged in physicians when alarm calls are received and awakened in the night with bad news. Various laboratory based study on the other hand had observed the shortening of QT interval during stressful interviews. However, the effect of stress on QT interval and QT dispersion (SDQT) is subject to speculation in healthy young adults. These previous reports provide conflicting data on the effect of stress on QT interval and also there exists a paucity of literature about the stress, quality of sleep, and their QT variables among young adults (17),(18),(19),(20),(21),(22). Hence, this observational study aims to assess the correlation of quality of sleep, stress with QT intervals, SDQT, and other QT variables among young adults.

Material and Methods

This cross-sectional observational study was undertaken in the Electrophysiology Laboratory setting of All India Institute of Medical Sciences, Mangalagiri, Andhra Pradesh, India, from October 2019 to March 2020. Ethical approval was obtained before conducting the research, from the Institutional Ethical Committee (IEC/AIIMS/Mangalagiri/2020-21/11). Written informed consent was obtained from the participants after explaining the objectives and the procedure in the language they could comprehend.

Sample size calculation: The sample size determination was carried out by using G power statistical software for analysis. With an effect size of the study at 0.5 (Desired=<1), keeping the power of the study as 0.95 (95%) and significance level (p-value) at 0.05, the minimum required sample was estimated to be 54. In this study, however, the whole sample/total population sample was used i.e., first and second year medical students aged 18-24 years were approached to participate in the research.

Inclusion criteria: Apparently normal young adult medical students with no history of depression who provided written informed consent were included in this study.

Exclusion criteria: Participants with any established obstructive coronary artery disease, unstable coronary syndromes, or those with obstructive sleep apnoea were not considered to be part of this research.

A purposive sampling technique was adopted to recruit the participants in the study. A Guided-self-administered structured questionnaire proforma was designed to include four sections viz., socio-demographic details; MSSQ; PSQI and QT interval recording format.

Medical Student Stress Questionnaire (MSSQ)

MSSQ was developed to recognise the stressors of medical students and assess the stress level induced by these stressors. It is a self-reported, self-scoring instrument with 40 items categorised into six domains namely the ARS, Teaching and Learning Related Stress (TLRS), Interpersonal/Intrapersonal Related Stress (IRS), Social Related Stress (SRS), Desire Related Stress (DRS) and Group Activities Related Stress (GARS), these were measured as domains of stress by the MSSQ (11). The investigator held few face-to-face sessions with the students related to a guided self-administered questionnaire and asked the participants to fill in the MSSQ, the answered questionnaires were collected on the same day. The students rate the intensity of stress caused by each item on a scale of 0-4 (causing no stress to causing extreme stress). The cumulative mean values for each of the six domains were taken to calculate the MSSQ score.

Pittsburgh Sleep Quality Index (PSQI)

PSQI has diverse utilisation in research and clinical settings, including the assessment of quality of sleep and identifying/classifying the sleep problems during the previous month (23). It can also be used to screen for sleep disorders at night and to monitor the development of sleep disorders. The PSQI consists of 21 questions categorised into seven components and each scored 0 (no difficulty) to 3 (severe difficulty). The cumulative component scores were obtained ranging from 0 to 21 to produce a global score, where higher ratings indicate a worse quality of sleep. A global PSQI score of >5 has shown that it has high diagnostic sensitivity and specificity in measuring the poor sleep quality, relative to clinical and laboratory measures and hence the same was used in this study to differentiate between good sleepers (<5) and bad sleepers (>5) (23),(24).

Measurement of QT Interval

The skin preparation, electrode placement, and associated protocols were identical to the developed guidelines. Physiograph- three channels and MLU268/8 LabChart software were used for recording 5-minute 12-lead resting ECG and QT interval, corrected QT interval (QTc), SDQT respectively. Volunteers were assuming the supine position. Vital parameters like resting heart rate, blood pressure were recorded. Twelve lead ECG was taken while resting in a room with a comfortable temperature of 22-25°C at a speed of 25 mm/sec with a gain of 10 mm/mV. Uncorrected QT interval, Corrected QT interval, SDQT were calculated from 12 lead ECG. The uncorrected QT interval was identified from the beginning of the Q wave to the end of the T wave. QTc was calculated by Bezett’s formula QTc=QT/vRR and QTd was calculated as the difference between shortest and longest QT interval recorded utilising a standard 12 lead ECG.

A semi-automated berger template matching algorithm was used for the reliable estimation and description of QT interval variability. The QT intervals was calculated as the difference between the Q wave onset and the T wave endpoint (i.e., QT end interval).

Unstressed/Prestress (T1) and Stress (T2) Time Periods for Data Collection

All the parameters were assessed at two different time points (T1 and T2). T1 being the unstressed (or) Prestress measures, were taken at the beginning of the academic year and T2 measures were taken during “stressed time”, three weeks before the term-end examination.

Statistical Analysis

The collected data was compiled systematically in a Microsoft Excel sheet. All statistical tests were carried using version 19.0 of SPSS (IBM SPSS, Chicago, USA). The distribution of the data was determined by the Kolmogorov-Smirnov test. Demographic data observations and QT variables were expressed as mean, Standard Deviation (SD), and range values for both the comparable classes. The difference in parameters between prestress and during stressed conditions was analysed using paired t-test. In case the data was found to be showing a non normal distribution, the Mann-Whitney U test was used for statistical inference. At a confidence interval of 95%, the test was considered “Highly Significant” if it yielded p<0.001. The p-value <0.05 was taken as ‘Significant’.

Results

A total of 68 medical students participated in the study. Eight participants were not available for the data collection during the T2 (stress time) assessment of variables. The mean age of 60 (34 males and 26 females) participants who completed the study was 19.8±1.19 years. The Mean GPSQI score of 4.50±2.87 was recorded in unstressed conditions was well under limits to rule out poor quality of sleep. However, the mean score of 6.03±2.76 during the stressed conditions was significantly higher indicating poor quality of sleep (p-value <0.001; PSQI >5). The “stressed” mean scores of QT, QTc, QTmin, and QTcmin measured were significantly higher compared to the “unstressed” mean scores among the medical students. Although, there was a comparative increase in mean scores of ARS, TLRS, SRS, DRS, and GARS, but only ARS showed a highly significant increase during the stressed conditions (p<0.001) (Table/Fig 1).

All the stressor domains of MSSQ showed a weak correlation with sleep quality during the unstressed times, however there was a significant moderate positive correlation observed between ARS and DRS with sleep quality during the term-end examination period indicating that academic stress influences the low quality of sleep (Table/Fig 2).

During the initial “unstressed” period, Global PSQI had a moderate negative correlation with QT interval measures. QT, QTmax, QTmin, QTcmax, and QTcmin measures had a weak negative correlation with ARS, while QTc, SDQT, and SDQTc had a weak positive correlation with the MSSQ scores. Overall, compared to the MSSQ scores, which failed to reach a significant correlation with QT interval measures; quality of sleep (GPSQI) had a significant negative correlation with QTc, SDQT, corrected SDQT, QTmax, QTcmax and QTcmin (Table/Fig 3).

During the “stressed” period, QT interval measures had a moderate correlation with academic-related stress scores. Quality of sleep had negative correlations with all QT interval measures except for QTc and QTcmin (Table/Fig 4).

Discussion

In this study, authors found insignificant elongation of the QT interval in ‘stressed’ medical students, which is in line with many studies reporting significant QT interval prolongation in stress (13),(20),(25),(26). However, this finding contradicts with the other similar researches, reporting significant QT interval shortening under stress (15),(27),(28),(29).

This study showed that both stress and sleep quality correlated with the prolongation of QT interval measures. Perceived stress has been recognised as one of the major factors resulting in poor sleep quality, delay in onset of sleep, increased daytime dysfunction as a result of sleepiness, and decreased quality of subjective sleep. In the present study at both (unstressed and stressed) time points, stress levels correlated with the GPSQI-score, supporting previous findings suggesting a close inter-relationship between these two factors (30). Various researches had found evidence regarding the close link of sleep and stress with the Hypothalamic-Pituitary-Adrenal (HPA) axis, which explains the near inter relationship between these two variables (31),(32),(33).

Mental stress can result in imbalance of the ANS, adrenergic release, increased sympathetic tone, contributing to heterogeneity of ventricular depolarisation resulting in prolonged QT interval. The QT interval has proved its clinical significance as a reliable clinical index in assessing the length of ventricular repolarisation, as prolonged QT and QTc reflects an increased risk of primary cardiovascular events among persons without clinically recognised heart disease (26),(28),(34). Prolongation of the QT interval is considered as one of the markers of such an imbalanced distribution of the activity of the sympathetic nervous system in the heart and is also assumed to be linked with a lower threshold for ventricular fibrillation and a risk of sudden cardiac death (26),(35). Routine monitoring of the QT-related parameters such as QT, QTc, QT variability, QTd may help prevent a major cause of cardiovascular impairment and allowing for more efficient preventive intervention by identifying early changes in otherwise safe subjects' biological parameters (28). This aspect might have important public health implications, by reducing the direct and indirect costs of cardiovascular disease in medical personnel. A cognitive behavioural approach, such as meditation or progressive muscle relaxation, might help medical students, reducing stress and thus increasing the quality of sleep.

This study has several strengths. First, a cross-sectional research design was used, which was able to investigate the possible correlation between the medical students’ sleep quality, stress, and QT interval measures. Second, to measure stress among medical students, the MSSQ is a valid, reliable, and well-established measurement instrument. Thus, a comparison can be made with previous studies. Considering the limitations and strengths, this study should be interpreted with caution and within its context. However, the present study can be used as the basis for planning longitudinal or cross-sectional studies with a larger sample size.

Limitation(s)

Despite these promising results, this research has some limitations. First, this study involved a relatively small number of study subjects that might compromise the accuracy of the results obtained from the analysis. Second, this study was limited to the cohort of only medical students studying in a medical institution, restricting the generalisability of its findings. The majority of the correlation coefficients were below/nearly 0.3 in this study which can be considered as small to medium effect size and may not have reached significance with a smaller size. The association between GPSQI and QT interval measures seemed slightly stronger than stress (ARS) and the QT interval measures, especially noticeable in the partial correlations QT, QTc, SDQTc, and QTcmax. ARS scores and QT remained significant with the correlation between stress and the QT interval during the stressed time. The causal relationship between sleep, stress, and QT interval measures remains unknown and cannot be determined by this study. The findings, however, further underline the critical interaction between these variables. Last, authors did not explore the possible causes of poor sleep quality and poor general health; also both PSQI and MSSQ assess participants during the past month or less and hence authors could not discriminate between acute and chronic problems.

Conclusion

In this study, authors have highlighted the influence of stress, quality of sleep on QT interval measures. The findings indicate that stress primarily influences the QT variability, but there is no major effect on the duration of QT. Both standard deviation of QTc and QT measure reflects the difference in variability between ‘Stressed’ and ‘Unstressed’ times among the medical students. Present study findings suggest the possibility of a mechanism linking emotional stress to changes in autonomic balance and ventricular repolarisation as indicated by QT interval prolongation. However, as such, no definitive conclusions have so far been drawn as to the specific QT interval response to stress conditions and poor quality of sleep. Authors supposed that further insight into QT changes related to these two distinct psychophysiological entities would help us to explain the varying reports on the effects of poor sleep quality and stress-induced QT changes in medical students.

Acknowledgement

Authors would like to thank Mr. Syed Ghouse Mohiuddin, Laboratory Technical Assistant, AIIMS, Mangalagiri, Andhra Pradesh, India, for providing the technical support throughout the data collection.

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DOI and Others

10.7860/JCDR/2021/50023.15386

Date of Submission: Apr 20, 2021
Date of Peer Review: Jun 12, 2021
Date of Acceptance: Jul 23, 2021
Date of Publishing: Sep 01, 2021

AUTHOR DECLARATION:
• Financial or Other Competing Interests: None
• Was Ethics Committee Approval obtained for this study? Yes
• Was informed consent obtained from the subjects involved in the study? Yes
• For any images presented appropriate consent has been obtained from the subjects. No

PLAGIARISM CHECKING METHODS:
• Plagiarism X-checker: Apr 21, 2021
• Manual Googling: Jul 22, 2021
• iThenticate Software: Aug 17, 2021 (18%)

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