Chinese Research on Myocardial Infarction – A Scientometric Study

A Myocardial Infarction (MI), commonly known as a heart attack, occurs when blood flow decreases or stops to the coronary artery of the heart, causing damage to the heart muscle. This investigation is a pioneering effort to depict the scientific output of myocardial infarction research especially in China using the data downloaded from Scopus database for a period from 2001 to 2020. The study proved that Chinese scholars are interested in collaborative research rather than solo research. The study deviates Bradford’s law of scattering. The highest productive journal in this field, as chosen by Chinese scholars is Chinese Medical Journal followed by International Journal of Cardiology (United States) and Medicine (United States). Wang, Y ranks first with 922 publications followed by Zang, Y and Li, Y having 849 and 739 publications respectively. More than one third of the references are of less than 5 years old.


INTRODUCTION
A Myocardial Infarction (MI), commonly known as a heart attack, occurs when blood flow decreases or stops to the coronary artery of the heart, causing damage to the heart muscle. The most common symptom is chest pain or discomfort which may travel into the shoulder, arm, back, neck or jaw. Cardiovascular diseases (CVDs) are the leading cause of death globally, taking an estimated 17.9 million lives each year. (WHO). 1 Approximately 1.5 million cases of MI occur annually in the United States. More than four out of five CVD deaths are due to heart attacks and strokes, and one third of these deaths occur prematurely in people under 70 years of age. Joshua Chadwick Jayaraj et al. 2 found that although the incidence of MI is decreased in the industrialized nations partly because of improved health systems and implementation of effective public health strategies, nevertheless the rates are surging in the developing countries such as South Asia, parts of Latin America, and Eastern Europe.

Previous studies
Zhou, H et al. 3 evaluated the global scientific output of gene research of myocardial infarction for the period from 2001 to 2015, using bibliometric methods. The data for the research was downloaded from Web of Science. It was found that there were 1,853 publications on gene research of myocardial research from 2001 to 2015, and the annual publication number increased with time. The journal Circulation published the highest number of articles. United States ranked highest in the countries with most publications, and the leading institute was Harvard University. Relevant publications were mainly in the field of Cardiovascular system cardiology. Donatella Ugolini et al. 4 analysed scientific production in the field of cerebrovascular and cardiovascular disease (CCD) rehabilitation. The total records downloaded from Pubmed for the period from 1967 to 2008 was 10379. The growth rate was 8.6 times in 40 years. The overall scientific production in the field of CCD rehabilitation showed a steep growth in the last decade, especially because of cerebrovascular research. The European Union and the United States contributed 3 of every 4 articles in the field, although some Asian countries showed promising performance. Ma Dan et al. 5 found that research on exosomes is flourishing in the cardiovascular medicine. Regenerative medicine, exosome engineering, delivery vehicles, and biomarkers will likely become the focus of future research. Sadeer Al-Kindi et al. 6 found that Middle Eastern countries produced only 3% of the total number of CVD research articles in the world. However, the overall trend showed an increase in the number of articles over the years, mainly from Turkey and Iran. Within this region, the ratio of CVD to non-CVD publications was highest in Qatar (0.23). Lebanon ranked first in the number of CVD publications per million persons (PMP) averaging 194.2 publications PMP' A search for research papers in the field of myocardial infarction shows that very few studies are available and most of the studies are in the field of bibliometric analysis in cardiovascular diseases. Majority of the studies were based on PubMed or Web of Science databases. Hence it is proposed to conduct an analysis of research literature on Myocardial infarction using the data available in Scopus database with special reference to China.

Objectives
This paper attempts to answer the following research questions. RQ1: What is the trend of myocardial research in China?
RQ2. What is the pattern of authorship?
RQ3. Who are the high productive authors?
RQ4. What is the referencing pattern of scholars in this field?

Methods
The data for this investigation was downloaded from Scopus data covering the years from 2001 to 2020 using author keyword "Myocardial Infarction". 14865 bibliographic records were downloaded and the data in the text format with tags were converted into MS Access database using Visual Basic 6. Necessary tables are generated using SQL. marks the highest growth rate (0.64) and the year 2020 has the least growth rate (0.03). However, it is found that from 2011 to 2020 the research productivity has growth to 218 folds.

ANALYSIS AND DISCUSSION
The authorship pattern shows that there are very negligible percentage of publications OFS of solo research (0.90%). As the number of authors increases from two to six, the number of publications also increases. The inference is that the optimum number of scholars in collaborative research is six. Here it is to be noted that, nearly 85 per cent of publications are the results of collaborative research by less than ten authors.
The total number of journals that have contributed to myocardial infarction research is 1531 of which 36 are core in nature. The highest productive journal in this field, as chosen by Chinese scholars is Chinese Medical Journal followed by International Journal of Cardiology (United States) and Medicine (United States). An application of Bradford's law of scattering to this field shows that the three zones are in the ratio 35:121:1375 = 1: 3.56: 38.28 which is not in the ratio 1:n:n 2 . Hence the study deviates Bradford's law of scattering.
Among the total publications, 23.10 per cent of the papers do not receive any citation at all and more than one fourth of the papers Core journals.

Biomedicine and Pharmacotherapy 75
Catheterization and Cardiovascular Interventions 75 Resuscitation 72 Heart Rhythm 72 Bradford's law of scattering. have citation count above 10. The interesting fact is that nearly 50 per cent of the papers have one to ten citations.

Zones No of journals No of papers
Cited references are the bibliographic details of materials consulted for research. The more the number of references, the high will be standard of the research papers. The research shows that 7.53 per cent of the papers do not have references and 11.93 per cent of the papers have less than 10 references. Nearly one fourth of the papers (25.48%) have 21-30 references. Also, 8.00 per cent of the papers have more than 50 reference.
The study shows that 408632 are appended to 14865 publications in myocardial infarction research in China. That is, on an average there are 27.5 references to a paper. Among the references, 11872 (2.91%) papers do not have the year in the bibliographic data. The age of the reference shows that 1.8 per cent of the reference are current in nature i.e 1.86 per cent of the references are of current ones (reference belonging to the same year in which the paper is published. B.E. Turvey, J.L. Freeman 7 notes that recency effect is a cognitive bias in which those items, ideas, or arguments that came last are remembered more clearly than those that came first. Here the recency effect of referencing is the quantum of references which are current (5 years old). In this investigation more than one-third (37.32%) of the references has recency effect. Also, it is observed that more than 70 per cent of the references are 10 years old.
The total number of Chinese scholars who have contributed to Myocardial research is 34343 of which Wang, Y ranks first with 922 p0ublications followed by Zang, Y and Li, Y having 849 and 739 publications respectively. Here it is to be noted that 69.5 per cent (n = 23889) of the authors have contributed only one paper. Also, except Zang, J and Wang, L, the other top ten ranked authors have not published any paper without collaborative effort.

FINDINGS AND CONCLUSION
This investigation is a pioneering effort to depict the scientific output of myocardial infarction research especially in China. While analyzing the research trend, the study shows the authorship pattern, referencing pattern and the high prolific authors in this field. The study proved that Chinese scholars are interested in collaborative research rather than solo research. The study deviates Bradford's law of scattering. The highest productive journal in this field, as chosen by Chinese scholars is Chinese Medical Journal followed by International Journal of Cardiology (United States) and Medicine (United States). Wang, Y ranks first with 922 publications followed by Zang, Y and Li, Y having 849 and 739 publications respectively. More than one third of the references are of less than 5 years old.