The clinical issues of sports cardiology is given much space in this book According to the ideas were elaborated by the founder of clinical avenue in sports medicine, A G. Dembo, the responce of CVS to the impact of physical loads, adequate to functional reserves of the body, does not go beyond the boundaries of physiological reaction. However, in cases, when loads obviously exceed adaptive capabilities of the body, there arises a real posibilitv for development of CVS overstrain with all apparent concequences, One could be in error considering the latter situation typical only for top results in sports disciplines. Any kind of sporting activity that is physical trainings, aimed at attaining previously inaccessible result, is open to physical overstrains. This situation is not at all rare for health-improving physical trainings, especially with the element of competition being introduced into them.
At the same time, the danger of physical and psycho-emotional overstrains resulting from sports activity is evidently underestimated by sports physiologists due to their occupational orientation and very often they are not taken into account by clinical cardiologists, since even obvious cardiac pathology in physically-trained individual sometimes proceeds atypically, it is well compensated over a long period of time and is not accompanied with complaints. That is why so little attention is likely to be paid to EGG changes, high frequency of complicated arrhythmias and other deviations in CVS morphology and functions in athletes
That is the reason why we saw our primary aim in attracting attention of physiologists and physicians to clinical problems of sports cardiology. Not minmizing the great importance of regular physical exercises in strengthening health and enhancing functional state of an individual, we do consider our chief task is to demonstrate that the border between norm and pathology, as well as between health and illness is rather provisional, and regular physical-training exercises are able not only to beneficially affect health and physical efficiency, but also lead to adaptation distress, favour the growth of prepathological condition and pathological changes in CVS.
No less essential for clinical practice is the idea of the excessiveness of physical overstrains, under which A G. Dembo has justly understood a discrepancy between adaptive capabilities of a body and load to be performed. The idea of physical loads excessiveness is sufficiently all-purpose one and adaptable to an athlete performing loads, enormous in volume and intensity and to an individual being very distant from sports, but involved in physical training to improve his health. In either case an inconsistency between the requirements imposed on a body and its CVS and physical state is open to the growth of overstrains.
For proper evaluation of adaptive shifts arising as a response to regular physical training, the knowledge of specificity of vegetative functions forming in answer to regular effect of physical trainings
of various orientations is of no small importance. The point is that the preferential training of such physical qualities as speed, endurance and strength leaves its mark not only upon the peculiar development and function of neuromuscular apparatus, but also creates specific harmony of vegetative functions. In particular, it has been possible to reveal tangible distinctions in CVS morphology and function in athletes with different orientation of the traininig process
Speaking about the impact of physical training on CVS, it is common practice to confine oneself referring to «classical» triad of evidences revealed at rest - bradycardia, arterial hypotension and myocardial hypertrophy. Today this triad requires a number of supplements and more precise definitions First of all, these evidences are typical not only for athletes in general, but also for sportsmen engaged in endurance-training. However, these evidences do not nearly so exactly and fully reflect these adaptive shifts that occur during such training. Firstly, bradycardia is rational only to a certain limit and if it goes beyond these very provisional limits, there arises a necessity to exclude the disorders of sinus pacemaker function.
As to myocardial hypertrophy, here, thanks to extensive application of echocardiography, we can advocate that sports training more likely leads to tonogenic dilation of cardiac cavities rather than toliypertrophy. Myocardial hypertrophy, proper especially the one, accompanied by the disorder of diastolic function, should be considered as a manifestation of impairment of cardiac adaptation to physical loads.
Arterial hypotension is also far from being considered as a physiological response to regular training. It also could be the manifestation of disorder of circulatory system regulatory apparatus or the result of toxic effect of chronic infection foci upon vessels. The significant supplement to this triad of indications is the characteristic of blood-circulation type with differentiation according to the definition of cardiac index, -hypo-eu- and hyperkinetic types Today, it is valid to say that for physiological adaptation to endurance-training, typical is the formation of hypokinetic type of circulation.
On the contrary, strength-training exercises are not accompanied with the formation of the above indications It is in the course of strength-training that the genuine myocardial hypertrophy arises and the decrease of its compliance starts
The complexity of estimation of physiological sports heart and estimation of the boundary, behind which physiological shifts terminate and prepathological changes begin, is in the fact that myocardial hypertrophy in athletes practically does not reach the dqgree of manifestation that can be observed by cardiologist in a clinic or it cannot be revealed at all, by means of instrumentation.
However, it does not mean that myocardial hypertrophy is entirely absent As it was demonstrated by home morphologists in the initial stage, myocardial hypertrophy can be of «nidus» type and is only revealed cytomorphologically. Doppler-echocardiography (DEchoCG)
holds out some hopes for early detection of myocardial hypertrophy at the stage when there is only a disorder of its diastolic function.
In general, for complete and proper estimation of CVS functional state, the current clinical and functional diagnostic examination of an athlete should be all-embraced with a number of instrumental methods being involved into it Among these «first-row» methods mention should be made of rhythmographic analysis, ECG in 12 conventional leads made at rest, exercise-ECG and also DEchoCG. Execise-ECG is of special significance among functional tests used in sports medicine It is important to emphasize that the use of the so-called «dozaged» physical loads (running on the spot, squatting and the like), have lost their significance today. Also, the revision of conventional assessment of the results of hemodynamic response to the test with physical load is evident
Instead of five responses to the load which are currently taken to be distinguished, we consider to restrict our study to three of them; physiologically adequate, physiologically inadequate and provisionally pathological responses.
While working at the monography, our primary emphasis was put on the problem of cardiac pathology in the course of sports • activity. The necessity for solving this problem is currently confirmed by increasingly higher detection of deviations in health condition of top-class athletes, by presence of complicated arrhythmias in them and high percentage of exercise-related deaths.
The causes of CVS pathologies in athletes can be divided into external and internal ones. Into the first category one can place sports stress itself with two of its components-physical and emotional, and also a number of other environmental factors, including the peculiarities of natural conditions in the course of training and competitions, quality of food, intake of drugs and dopes, etc.
The internal causes conducive to the development of prepathological condition and pathological changes of circulatory apparatus are in the genetic determination of physical abilities and also in the occurrence of cardiac and vascular anomalies. The combination of external and internal factors, the contribution of which in each particular case is undeniably diverse, is capable to bring to adaptation distresses and development of CVS pathology in the course of sports training.
Among the prepathological conditions arising in athletes and creating favourable background for further decline of body’s adaptive capabilities, the foci of chronic infection(FCI) should be mentioned first. Their occurrence should be regarded as a result of the effect upon the body unfavourable external factors (training exersises in enviromentally-adverse conditions, pxiysical and psycho-emotional stresses, etc.) coupled with altered immunologic reactivity due to overstrain.
Only the set of medical-preventive and pedagogical measures is able to create conditions to sanify the foci of chronic infection and impede the complications initiated owing to their existence.
From the point of view of clinical significance of arterial hypo-and hypertension, the attitude to them is far from being equivalent Arterial hypotension should be considered as clinically-significant only in such cases where it is combined with the decrease of sporting and general efficiency and/or with the appearance of signs of CVS disadaptation to physical loads.
The clinical significance of arterial hypertension in persons engaged in sports disciplines is unquestionably higher. The very fact of revealing increased pressure at rest, especially in endurance-training athletes, should «риск up physician’s ears» and requires to settle the problem on the possibility to be engaged in sports activity. It is pertinent to note that in this case one can deal only with the cessation of sports but not with sanative trainings, since the latter are especially beneficial for a person adapted to physical loads.
The results of comprehensive clinical-instrumental examination can be of help in coming to a vital decision on the possibility to continue training exercises of athletes with arterial hypertension. Needless to say, that this should be in case when a physician is not called on to take a decision on admittance to trainings or competition - the professional athlete has a right to take over the responsibility to continue his sporting career. In such cases the duty of a physician is to select adequate hypotensive therapy, the consideration of which is within the context of the present monography.
There will be no exaggeration to say that the evolution of myocardial dystrophy conception due to overstrain was one of the primary tasks facing the author. Pathological changes on the heart, revealed in athletes by our western colleagues are not uncommon defined as secondary cardiomiopathy. In should be emphasized that we do not see fundamental differences in using one or other terminology to define myocardial pathological changes associated with physical or psycho-emotional sporting overstrains.
More important is to acknowledge the fact that stressor impacts per se, unfaillingly accompanying sporting activities, are able to become the cause of numerous manifestations of «pathological sporting heart» and that clinical ^roptomatization and myocardial morphological changes in the form of its hypertrophy, fibrosis and so-called idiopathic calcinosis are in the majority of cases the result of overstrain rather then hereditary-determined illness- hypertrophyc cardiomyopathy. In this case, the impact of hereditation on the formation of myocardial dystrophy at physical loads is undeniable and very high Here we are dealing with hereditary-determined power of stress-limiting systems and also with systems of adenosine triphosphate resynthess and Ca++ pump [Меереш ФЗ, 1993J
No less important is the fact that polypathogenicity of myocardial dystrophy creates conditions for diversity of clinical manifestations of this state. At the same time, frequent absence of complaints and scanty clinical picture of myocardial dystrophy, stemmed from overstrain with retention of comparatively high efficiency, constitutes
a threat to hypodiagnostics and demands the employment of the whole arsenal of instrumentation. Timely diagnostics of myocardial dystrophy in athletes is all the more importance, since today the availability of a number preventive measures and drugs allow a physician and a coach to use them in order to guard against and to treat a progressing, «in leisurely fashion», pathology.
Very close to the problem of myocardial dystrophy in athletes are the issues of diagnostics and clinical estimation of cardiac arrhythmias. Though the vast majority of athletes cardiac arrhythmias should be considered within the context of CVS physiological adaptation responses to regural physical trainings, part of them, undoubtedly, is one of the myocardial dystrophy symptoms. In the scope of arrhythmic version of clinical course of overstrain dystrophy, from our standpoint one should consider a number of cases of so-called arrhythmogenic left-ventricular dysplasia.
The study of arrhythmogenic version of myocardial dystrophy clinical course showed that arrhythmias in athletes were rarely the only manifestation of myocardial dystrophy. As a rule, with the help of up-to-date instrumental investigations, the disorder of myocardial diastolic function, electrogenesis changes, hypertensive response to load test, etc., are revealed.
Of topical importance is the point regarding the effect of abnormal development of valvular apparatus and subvalvular structures upon the adaptation to physical trainings. Our experience and still a modest number of publications, dealing with this problem, show that the occurrence of such abnormalities should be looked upon as a risk factor of myocardial dystrophy stemming from overstrain.
As to interconnection between the level of physical activity and lipid metabolism, today, the date for favourable effect of physical trainings upon lipid metabolism and possibility of primaiy prevention of cardiac ischemia with the help of physical exercises look not so unamliguously. In any case, today, the statement can be made that the directionality of physical training effect on cholesterol homeostasis is determened not so much by the volume and intensity of loads, as by the character of nutrition and genetically-determined features of lipid metabolism.
As regards to sudden death in sports, the solving of this problem or, in any event, the approaches to its solving, should follow the routes aimed at the development of preventive measures in sports medicine, meticulous selection of individuals for sports and all-round examimation of athletes at the stages of mastering sporting skills, early diagnostics of CVS disorders in adaptation to physical trainings, wide applecation of preventive measures and treatment of myocardial dystrophy stemmed from overstrain.
The data presented in this book give an idea how complicated and diverse are the issues facing a physician dealing with the examination of persons engaged in regular physical trainings and how often these issues do pass from the domain of estimating the norm into the domain of solving clinical tasks of physiology.
Спортивная кардиология, Земцовский Э.В., 1995
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