Analysis of Heart Rate Structure in Screening Diagnosis of Primary and Secondary Renal Arterial Hypertension in Children

The research is dedicated to the analysis of heart rate structure as a potential tool for screening diagnosis of primary and secondary renal arterial hypertension in children. The relevance of the work is determined by the high prevalence of arterial hypertension in the population of both adults and children, as well as the need to develop effective methods for differential diagnosis of primary and secondary etiology of the disease. The work evaluates the possibility of using heart rate structure analysis for recognizing the type of arterial hypertension in school-age children, investigates the relationships between heart rate rhythm characteristics, blood pressure levels, and phenotypic signs of metabolic syndrome.

The scientific novelty consists in the first-time proposed method of differential diagnosis of primary and secondary arterial hypertension in children based on heart rate structure characteristics, as well as in the identified relationship between heart rate rhythm characteristics and phenotypic signs of metabolic syndrome. The practical significance of the work lies in the implementation of the developed decisive rules for differential diagnosis into mass preventive examinations of children and into the practice of hospital pediatrics.

Relevance of the problem. Arterial hypertension is one of the most widespread diseases in developed countries, affecting 15–30% of the adult population. By reverse definition, as stated in the recent report of domestic hypertension experts (DAG-i, 2000), AH "is the greatest infectious pandemic in the history of humankind, determining the structure of cardiovascular morbidity and mortality." It predisposes to the development of such fatal complications as ischemic heart disease, myocardial infarctions, cerebral strokes, chronic renal insufficiency, life-threatening cardiac arrhythmias, and circulatory insufficiency. Due to its wide prevalence, the multi-faceted nature of organ and system damage, the treatment of AH has become an interdisciplinary problem. In the United States, arterial hypertension is detected in almost 58 million adults, the majority of whom have primary or essential hypertension (Sharma A., Smaiko A., 1995). In Russia, approximately 30 million people (20% of the population) suffer from arterial hypertension. Among men of active age (20–54 years), the prevalence of arterial hypertension ranges from 25.2% to 44.8%, averaging 33.6% (Arabadze G.G., 1999; Konstantina V.V., 2001).

It is known that the origins of hypertensive disease in adults should be sought in the prenatal, childhood, adolescent, and young adult periods.

During mass epidemiological examinations, arterial hypertension in children is detected in 6–14% of cases and is assessed as a vegetovascular dynasty of hypertensive type. Over the subsequent 3–7 years, blood pressure normalizes in almost half of these children; however, in 33–42% of children, blood pressure does not normalize, and in 17–26% of cases it increases even further (Belokon N.A., Kubyserger M.B., 1987; Sambhi M., 1982). In children with sustained hypertension, targeted inpatient examination reveals a secondary genesis in 45–85% of cases (Belokon N.A., Kubyserger M.B., 1987; S. Kapp A., Smaiko A., 1995). Tsyganiuk A.R. (1998) estimated the frequency of sustained arterial hypertension in children of all age groups at 1–3%, noting that in most cases it has a secondary (symptomatic) character.

The development of methods for differential diagnosis of primary and secondary arterial hypertension has traditionally been one of the most relevant directions of research in pediatric vasocardiology. Currently, in order to recognize the etiology of hypertension, diagnostic programs are used that include a detailed assessment of the anamnesis, a complex of instrumental and laboratory characteristics, including, among other things, the results of quite expensive and labor-intensive research methods.

The purpose of this work is to evaluate the possibility of using heart rate structure analysis in the differential diagnosis of primary (essential) and secondary renal arterial hypertension in children.

Research objectives:

1. Assessment of the prevalence of arterial hypertension in the population of school-age children, recruitment of experimental and control groups of children during actual preventive examinations.

2. Selection of a method of heart rate structure analysis suitable for use during mass preventive examinations.

3. Search for heart rate structure characteristics associated with blood pressure levels.

4. Search for heart rate structure characteristics associated with phenotypic signs of metabolic syndrome.

5. Evaluation of the possibility of diagnosing primary arterial hypertension based on a complex of heart rate structure characteristics.

6. Formation of decisive rules for differential diagnosis of primary and secondary arterial hypertension in children.

7. Verification of decisive rules during actual children's examinations.

Scientific novelty:

1. For the first time, a method of differential diagnosis of primary and secondary arterial hypertension in children based on heart rate structure characteristics is proposed.

2. For the first time, a relationship between heart rate structure characteristics and phenotypic signs of metabolic syndrome in children is identified.

Propositions to be defended:

1. Heart rate structure characteristics are sufficiently informative for the differential diagnosis of primary and secondary renal hypertension in children and are not informative for the differential diagnosis of primary arterial hypertension and secondary hypertension associated with hyperthyroidism.

2. The heart rate structure indicates that the basis of primary arterial hypertension in children lies in a violation of the autonomic regulation of vascular tone.

3. The use of heart rate structure characteristics makes it possible to recognize primary arterial hypertension not by a residual principle, which simplifies the process of establishing a diagnosis.

Practical significance and implementation of research results.

Since 2002, the method of differential diagnosis of primary and secondary arterial hypertension has been implemented in mass preventive examinations of children residing in the regions of the Russian Far North. Since 2003, the decisive rules for differential diagnosis of various types of arterial hypertension based on heart rate structure characteristics have been introduced into the practice of pediatric hospital medicine in a short-term stay inpatient facility.

1. The results of the work are presented and discussed at the international symposium "Living and Work in the North," Kostomuksha, October 28–30, 2003, at the European Conference on Human Genetics, Munich, November 12–15, 2004, at the scientific-practical conference "Paths to Improving Quality of Life in the North," Saint Petersburg, June 24–25, 2004, at the scientific-practical conference "Modern Problems of Cardiovascular Pathology in the Russian Far North," Yakutsk, November 17–20, 2004.

The main results of the conducted research are presented in 8 publications.

Volume and structure of the dissertation. The dissertation, presented on 143 pages of typed manuscript, consists of an introduction, 3 chapters, a conclusion, conclusions, and practical recommendations, includes 5 figures and 23 tables, and has 4 appendices. Discussion is conducted by sections. The bibliography includes 208 sources.