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9UOT: 612.67/68(478.9)+612.014.4 STUDY OF VARIABILITY OF AMPLITUDE AND INTERVAL INDICATORS DURING ELECTROCARDIOGRAPHIC EXAMINATIONS IN ELDERLY, SENILE AND LONG-
LIVERS OF AZERBAIJAN
GADIMOVA ZENFIRA MAMED
Doctor philosophy in Biology, Associate professor at the Institute of Physiology n.a. academician
Abdulla Garayev
AYYUBOVA GUNEL MAARIF
Doctor philosophy in Medicine, Azerbaijan Medical University Institute of Physiology n.a. academician Abdulla Garayev, Azerbaijan National Academy of
Sciences, Baku, Azerbaijan Azerbaijan Medical University, Baku, Azerbaijan
Annotation: Population aged 60 and more continues suffer from cardiovascular diseases of any old age group and coronary heart disease remains the leading cause of death in industrialized countries. During physiological study of the cardiovascular system in the elderly, elderly and long-liver groups, while analyzing the bioelectric activity of the heart, special attention was paid to the interval, amplitude, complex, duration and segment of the teeth (P, Q, R, S, T) that recorded in the electrocardiogram. By monitoring these indicators, it is possible to determine the changes in the heart rhythm and the structure of the myocardium. In our research, PQ, duration of QT interval, RR interval, amplitude of QRS complex, P wave were studied in elderly, senile and long-liver patients and changes in the bioelectrical activity of the heart due to age were determined based on the obtained results.
Keywords: Aging, elderly and senile patients, longlivers, cardiovascular aging, cardioamplitude, cardiointerval.
One of the biggest challenges of science and medicine is providing active longevity, which requires deeper understanding of intrinsic mechanisms underlying natural aging process. Cardiovascular diseases are the most common pathology and the most frequent cause of death among elderly people, with arterial hypertension being the main contributor to cardiovascular mortality. Age-related changes of cardiovascular system are thought to be influenced by genetic factors [3,8].
Biological aging is the main risk factor for many cardiovascular conditions and a determinant of long-term outcomes. The heart age has been used as a means of assessing the biological age of the cardiovascular system. It represents the age implied by a person's calculated cardiovascular risk assuming all other modifiable risk factors are within ideal ranges [4,11,13].
Solution of the problem of active longevity of the population is great social and national economic importance. The mode of life is one of the main factors in achieving active longevity.
The relationship and structure of the relationship between aging and disease is an important medical and biological problem. There are opposing points of view on this issue. According to one view, aging is inherently a physiological process. Proponents of this theory consider that, longlivers as representatives of the "physiological" type of aging.
The final aim of the problem of longevity is the struggle for a normal individual development as well as the prevention of a premature aging. For this purpose, the data of biology and medicine, ontogenesis and age physiology are used. Gerontology is a new science, and a speciality not only of biologic medical profile, but of social profile as well because the principal objects of its study is the old man. This requires studying functional peculiarities of the senile organism of man as an individual primarily in physiological aging. Therefore, in the beginning of our investigations in the field of gerontology we studied physiological peculiarities of the organism of old people at the age of 60 up to 90-100 and older. But disclose the genesis and mechanisms of aging it is necessary also to study comparatively the characteristics of the living flesh at different levels of its organization in the body and at different stages of aging.
It is known that the variability of electrocardiographic indicators decreases with age. It is very important to clarify the extent to which these results are related to the fundamental, and at the same time, bioelectric properties of the myocardial functional activity indicators [1,2,12,14]. There are different views in the scientific literature regarding the age characteristics of electrocardiographic (ECG) studies. Evaluating the changes in the ECG is difficult because of there are not exact norm criteria for the elderly, senile and long-liver age groups.
For this reason, it is very important to determine the age criteria for ECG, which is one of the widely used research methods of bioelectrical activity of the heart. The reason of the importance of ECG recording in gerontological age groups is related to its indicators can be used to observe dynamically the state of the cardiovascular system during the aging process. ECG is also important for detecting signs of premature aging of the myocardium [5,7,13,14].
In our gerontological studies in Balakan region, one of the main goals was to clarify the important characteristics of the bioelectrical activity of the heart in relation to age by determining the changes in the ECG in the elderly, senile and longlivers.
Material and methods: The studies were carried out in the North-West region of Azerbaijan, in Balakan region. We used the following age classification: elderly (60-74 year, n=50) and senile (75-89 year, n=50) age groups. In this research involved 42 longlivers, including 17 men and 25 women. Most widely for diagnostics of cardiac arrhythmias the electrocardiography (ECG) is used [6]. In registration of ECG we used 12 conventional standard assignments (I, II, III, aVR, aVL, aVF; V1-V6). ECG was registered with a speed of 50 mm/s. During the studies we used the device "CardiMax".
All obtained numerical indicators were analyzed on the basis of statistical-mathematical methods and formulas, taking into account modern recommendations. The obtained results were evaluated according to the Student's t definition test and the degree of integrity of the results was determined according to the Student-Fisher table.
Statistical processing of all mentioned indicators was done using "STATISTICA 6" and "Microsoft Excell (2016)" programs.
Results. Understanding the mechanisms that control lifespan is among the most challenging biological problems. Many complex human diseases are associated with aging, which is both the most significant risk factor and the process that drives the development of these diseases. The aging process can be regulated during evolution [8].
The ECG is a graphic representation of cardiac functioning that is known to reflect several features including normal ageing, disease states, and subject-specific characteristics. For example, age-related ECG changes, independent of cardiovascular disease (CVD), such as changes in QRS and T-wave amplitudes, cardiac activation patterns, and leftward axis shifts have been described. Similarly, specific ECG patterns in congenital and acquired CVDs (e.g. myocardial infarction, hypertension, etc.) have also been described [4,9,10,11].
During our research, ECG was taken to study the physiological and functional state of the myocardium in the aging process in gerontological age groups. In order to evaluate the bioelectrical
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activity of the myocardium, the amplitude, duration, interval between the waves, etc., are recorded in the ECG is calculated.
For elderly people, it is important to determine the prolongation or shortening of the PQ interval. It is known that the PQ interval is the time of transmission of the arousal from the atria to the AV node, the sensory bundle and its branches. In Balakan region, the general statistical indicators of the PQ interval in the elderly were 0.22±0.006 s., in the senile people 0.20±0.009 s, and in the longlivers 0.17±0.005 s.
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Fig.1. Parameters of PQ interval in elderly, senile patients and longlivers
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One of the important changes noticeable in the ECG of elderly and senile age groups, as well as longlivers, is the duration of the QT interval, which is the main indicator of the electrical systole of the heart. Prolongation of the QT interval in aging reflects the impaired performance of the aging myocardium. Prolongation of the QT interval depends not only on the change of the HT, but also on the change in the functional state of the muscle fibers of the myocardium, on the slowing down of the repolarization process in them. The QT interval was calculated as 0.32 ± 0.008 s in the elderly, 0.34 ± 0.014 s in the senile patients, and 0.37 ± 0.008 s in the longlivers. QT interval according to ECG norms is 0.34-0.42 s. If it is taken into account, it can be concluded that this interval is shortened in the elderly residents of Balakan region, as well as the electrical systole of the heart is also shortened.
QT
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elderly age senile age longlivers
Fig.2. Parameters of QT interval in elderly, senile patients and longlivers
Our study has shown that the QT interval increases with age in an apparently normal population. It has also shown that QT dispersion, which measures underlying inhomogeneity of myocardial repolarization, does not change with age. Several studies have shown that women have a longer QT interval than men. Our study did not demonstrate any significant difference in QT interval between men and women, but the data were not corrected for age and the sample size was small. Another explanation for the increased QT interval with age is an imbalance between sympathetic and parasympathetic tone. In the elderly, an exaggerated shift toward sympathetic activity has been reported. High sympathetic activity can lead to myocardial membrane properties that give rise to early after depolarization and dispersion of repolarization.
The duration of the QRS complex is slightly longer in elderly people, which proves the violation of the depolarization process in myocardial cells. The average statistical indicators of the QRS complex in Balakan region were calculated as 0.06±0.004 seconds in the elderly, 0.09±0.006 seconds in the senile, and 0.09±0.003 seconds in the longlivers.
As a result of calculating the RR interval in the ECG, the average statistical value of this indicator is 0.8±0.042 s in the elderly of Balakan region, 0.7±0.032 s in the senile people, and 0.7±0.025 s in the longlivers has been noted.
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senile age
longlivers
Fig.3. Parameters of QRS complex in elderly, senile patients and longlivers
RR
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0,8 0,6 0,4 0,2 0
elderly age senile age longlivers
Fig.4. Parameters of RR interval in elderly, senile patients and longlivers
During the aging process, conduction of excitation propagation in the heart becomes difficult at different stages. The process of arousal in the auricles is disturbed (deformation, expansion, crossing of the P wave), atrioventricular conduction, the rate of propagation of the arousal in the myocardium of the ventricles slows down a bit. In our studies, special attention was paid to the shape of the P wave in the analysis of the ECG analysis. In elderly people, the duration of P wave is 0.16±0.008 s.; 0.09±0.006 s. in the senile people; and in longlivers it was 0.11±0.004 seconds. An enlarged and crucified form of the P wave was noted in elderly patients.
P
***
0,16
0,14 0,12 0,1 0,08 0,06 0,04 0,02 0
elderly age senile age longlivers
Fig.5. Parameters of P interval in elderly, senile patients and longlivers
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In general, if we pay attention to the final results of the electrocardiographic analyzes of our research, we can conclude that the functional changes of the cardiovascular activity in the elderly and senile people living in Balakan region have a serious effect on the general physiological state of the body, against the background of complex diseases (diabetes, arterial hypertension, neurological, oncological, etc.) caused the acceleration of the aging process (pathological aging). It is these characteristics that may affect the decline of the longevity index for the region in the next decades. Based on the final results of the study of the bioelectrical activity of the heart of long-lived people, it can be noted that their adaptive-compensatory capabilities are more durable, and thanks to this, signs of the physiological aging process can be clearly seen in them (compared to wise and old people), and these long-lived people can be considered a clear example of physiological aging.
In gerontological studies, the old age period (60-74) is considered as a critical period of human life. This age period is characterized by a relatively active passage of involutive processes on the one hand, and a sharp increase in atherosclerotic processes on the other hand. Therefore, they calculated that the average life span in developed countries is in the range of 65-75 years. The natural decline process of the majority of the population also occurs during this age period. Looking at our scientific results, it is clear that changes in the structure, amplitude, interval, and segment of the denticles reflecting the bioelectric activity of the myocardium were more observed in elderly people than in other age groups.
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