PhD, Associate Professor I.A. Pogonysheva¹
PhD, Associate Professor D.A. Pogonyshev^1
1Nizhnevartovsk State University, Nizhnevartovsk

Keywords: cardiovascular system, screening analyzer CardioVisor-06c, dispersion mapping, physical load, premorbid conditions.

Introduction. Heart functionality is one of the most significant evaluation criteria for monitoring of the human body status under regular physical loads. Strenuous training loads often exceed the adaptive capabilities of the body. The cardiovascular system, as an indicator of functional changes occurring in the body under extreme loads, can respond by developing premorbid conditions characterized primarily by cardiac stress [8, 10]. In addition to physical activity, athletes from the Far North are also affected by adverse climatic and geophysical factors, which increase the load on all physiological systems [7, 8].

The cardiovascular disorders often develop asymptomatically and therefore often remain undiagnosed, thus increasing the risk of life-threatening conditions and sudden cardiac death. Domestic publications provide multiple evidence of development of myocardosis in professional athletes due to cardiac overstrain. According to V.S. Vasilenko, myocardosis incidence among athletes due to physical overstrain has increased five-sixfold over the past 40-45 years [1, 2, 5]. Juvenile age and compensatory reserves provide a long-term asymptomatic circulatory system disease course. To solve this problem the methods of early diagnostics of pre-pathological conditions in athletes should be used. Here computer screening analyzer "CardioVisor-06c" can be used, which operates based on the analysis of low-amplitude dispersion changes in the electrocardiogram followed by design of a visual heart portrait, where segments colours indicate the localization and degree of manifestation of premorbid conditions [9].

Objective of the study was to make preventive evaluation of the current heart functionality of sporting students for the purpose of early diagnostics of dysfunctions.

Methods and structure of the study. 70 sporting students (27 females and 43 males) aged 18 to 22 years participated in the study on a voluntary basis. At the moment of examination students neither complained nor had had any cardiovascular pathologies in their past medical history. Evaluation of heart functionality, with a subsequent dispersion analysis, was carried out using the computer analyzer "CardioVisor-06c" designed to make a rapid assessment of heart condition by ECG signals from the subject’s extremities. The following indices were used in the dispersion mapping: "myocardium" (or index of electrophysiological changes in the myocardium), "rhythm", heart rate (HR) - corresponds to the "pulse rate" index, indices of electrophysiological detailization (G1-G9). The "myocardium" integral index ranges from 0 to 100% and reflects the average amplitude of electrocardiogram (ECG) micro vibrations. The "myocardium" index, equaling 0%, testifies to the absence of significant deviations from the norm. The "myocardium" index, approaching 100%, indicates pathological processes. The myocardium values ​​less than 16% (assuming that G ​​tends to zero) are within the normal range of values, ranging from 16 to 19% (borderline) indicate possible cardiac stress, those more than 20% indicate possible latent dysfunctions, the values over 47% indicate a significant pathology. The "detailing code" characterizes: the degree of manifestation and localization of electrophysiological dysfunctions in the atrial and ventricular myocardium in the depolarization and repolarization phases (G1-G7), presence of intraventricular heart block (G8) and signs of myocardial hypertrophy or ventricular myocardial ischemia (G9). The values higher than 1 indicate the presence and degree of manifestations of electrophysiological disorders in the myocardium. G1-G9 gradations, equaling or approaching zero, testify to the absence of dysfunctions [9]. As an additional parameter of diagnostics we assessed the autonomous nervous system tone based on the "rhythm" index, which is an analogue of heart rate variability according to R.M. Baevskiy [3]. If sympathetic and parasympathetic effects are optimally balanced, the "rhythm" value ranges from 0 to 20%. If there are vegetative dysfunctions or tension of the regulatory systems, this index exceeds 20%. The "rhythm" value exceeding 80% corresponds to significant changes in the R-R-interval variability, indicating a pronounced arrhythmia or stress [4, 6, 9].

Results and discussion. The "myocardium" values less than 16%, indicating the absence of cardiac pathologies, were registered in 77.8% of young women whose "heart portrait" was characterized by mostly green tones. Moderate changes in the myocardium, premorbid cardiac conditions ("myocardium" value from 16 to 19%) were observed in 22.2% of female athletes. No pathological conditions ("myocardium" value exceeding 20%), characterized on the "heart portrait" screen by predominantly red tones, were observed in examined young women. The "myocardium" value less than 16%, indicating no significant disturbances, was registered in 67.4% of young men. Premorbid cardiac conditions were observed in 23.3% of young males, 9.3% of young men were diagnosed with pathological changes, quasiepicardium in the screen was characterized by predominantly red tones (Table 1).

In terms of the "detailing code" index, 16.2% of young men and 7.4% of young women had an insignificant divergence of G1 and G2 parameters, which characterize the right and left atrial depolarization process. The dispersion abnormalities, testifying to the presence of intraventricular heart blocks (G8), were not detected in subjects. Ventricle myocardium repolarization disturbances, which characterize G5 and G6 indices, were found in 18.6% of young men and 11% of young women, most often this condition is caused by chronic overstrain of the cardiovascular system. An increase in G5 and G6 values ​​may also indicate insufficient myocardial oxygenation. G9 refers to the most sensitive indices of premorbid and pathological reactions of the ventricular myocardium, its increase is indicative of the myocardial depolarization abnormalities. G9>0 was registered in 9.3% of male athletes. Such a situation can be observed both in case of ventricular hypertrophy and in case of left ventricular myocardial ischemia. Simultaneously increasing values of the "myocardium" index and G1-G9 indices, which indicate significant electrophysiological abnormalities, were found in 6.9% of male subjects.

Table 1. Dispersion characteristics of low-amplitude ECG, %

According to literature data, one of the most typical ECG characteristics of athletes is sinus bradycardia, or resting heart rate of under 60 bpm. Such a heart rate is often a norm for professional athletes, but for those not doing sports it may indicate a pathology and, thus, requires further diagnostics. Based on the research findings, moderate bradycardia was detected in 27.9% of male athletes and 11.1% of female athletes. 7.4% of young women and 9.3% of young men had increased myocardial oxygen demand, as evidenced by an increase in the resting heart rate indices, leading to strained cardiovascular functionality and reduction of chronotropic cardiac reserve (see Table 1). The signs of disorder in genesis of heart muscle cells action potentials and conduction of excitement (possibly, one of the types of arrhythmia) were detected in 3.7% of female athletes and 9.3% of male athletes. The signs of myocardial hypoxia were registered in 18.6% of young men and 11% of young women. The normal position of the electric axis of the heart was noted in 100% of the subjects of both sexes. The "rhythm" index values were within the normal range in 72.1% of male athletes and 70.4% of female athletes. The signs of tension in the body's regulatory systems were detected in 27.9% of young men and 29.6% of young women. According to the research findings, the vegetative system dysfunctions were observed in both of the groups of athletes, although young men had less pronounced vegetative disorders (see Table 1).

Conclusion. The study designed using the computer screening analyzer "CardioVisor-06c" has enabled to single out a category of sporting students who need to undergo comprehensive diagnostics to exclude a cardiovascular pathology. Athletes with the premorbid characteristics of the "detailing code" require further detailed medical examination and cardiology consultation. Thus, the use of the non-invasive monitoring of micro-alterations of the ECG will facilitate diagnostics of latent myocardial dysfunctions in athletes to warn them on a timely basis on the overloads in the training process in exceed of their individual resources and capacities that may result in overtraining conditions.

References

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Corresponding author: severina.i@bk.ru

Abstract

The study was designed to test the current heart functionality of sporting students from the Far North, with the tests designed using a computer screening analyzer CardioVisor-06c system that diagnoses cardiovascular system disorders on an off-clinical basis. The dispersion changes of ECG were applied to diagnose premorbid conditions and profile the general variations of the athletes’ myocardial functionality rates. The young men and women diagnosed with pre-pathological conditions as verified by the relevant specifics of electro-physiological details and vegetative system dysfunctions were referred to further detailed medical tests and cardiologic consulting service. It should be noted that the non-invasive monitoring of micro-alterations of the ECG will facilitate diagnostics of latent myocardial dysfunctions in athletes to warn them on a timely basis on the overloads in the training process in exceed of their individual resources and capacities that may result in overtraining conditions.