CC BY
2
UDC 616.13.
Altynbekov M.A.
teacher
International Kazakh-Turkish University named H.A. Yasavi
Turkestan, Kazakhstan MAJOR ELECTROCARDIOGRAPHIC ABNORMALITIES AND CARDIOVASCULAR DISEASES
Annotation. This article presents a study of the frequency of occurrence of major electrocardiographic abnormalities and their effect on the course of cardiovascular diseases. The types of major electrocardiographic deviations are considered according to the classification of the Minnesota coding system of electrocardiograms.
Key words: major electrocardiographic abnormalities, cardiovascular diseases, prevalence.
According to the Minnesota coding system, all electrocardiogram (ECG) changes are divided into two large categories - major and minor deviations. The category of major deviations are [1]:
- Cicatricial changes in the myocardium
-Isolated ST-T changes characteristic of myocardial ischemia
- Severe impairment of ventricular conduction
- Hypertrophy of the left ventricle (LVH) with changes in its myocardium
- Significant extension of the QT interval
- Atrial fibrillation
- Severe disturbances of atrioventricular (AV) conduction
- Other severe rhythm disturbances
The ratio of the amplitude of the wave Q/R >1 / 3, the duration of the waves Q >0,03 sec, the appearance of QS, the decrease of the ST segment below the isoline by >2 mm, at which the segment ST is horizontal or directed downward in any isotope, II or aVF are signs cicatricial changes of the myocardium [2]. There are data that Q/QS anomalies are more common in men [3]. The presence of cicatricial changes in the myocardium significantly worsens the course of cardiovascular diseases (CVD) and also causes an unfavorable prognosis. A large number of studies have studied the prognostic significance of cicatricial changes in the myocardium. Thus, in Sweden, 50-year-old men living in the city of Uppsala were invited to a prospective population-based cohort study to evaluate the prognosis of patients with Q/QS myocardial infarction in a history. The work involved 1221 people who were examined again after 20 years. Many participants at 70 years of age, with repeated Q/QS myocardial infarction, had a higher prevalence of diabetes, compared with the control group. The authors believe that the presence of Q/QS waves, regardless of the history of MI, is associated with diabetes, moreover, it is a predictor of overall and cardiovascular mortality [4]. In addition, the presence of Q/QS prongs increases the risk of death, even in individuals who initially had no changes on the ECG, which is shown in the work
of Japanese researchers during the 19-year follow-up period [5].
Among the major ECG abnormalities, ventricular conduction disturbances have also been sufficiently studied in many studies. Violations of ventricular conduction include right bundle branch block (RBBB). RBBB - is a violation of the conductivity of the pulse, as a result of which excitation by the usual way extends to the left ventricle and with delay to the right ventricle. There is a complete and incomplete blockade, the prognostic significance of which is different. If the complete RBBB is not widely distributed in the general population, then the incomplete RBBB is a frequent finding. It is believed that incomplete RBBB is a benign phenomenon [6], although there is evidence to the contrary [7]. There are also contradictory data in relation to the complete RBBB. If some believe that it does not represent any clinical significance [8], others find a link with a high risk of cardiovascular mortality [9,10]. To summarize the existing conflicting data, scientists from China and Australia conducted a study in which the authors analyzed prospective studies from the PubMed, EMBASE, and Cochrane databases. Nineteen cohort studies were included, with 201,437 participants and a follow-up period of 1 to 246 months. In persons with complete RBBB, the risk of myocardial infarction, mortality and hospital mortality was higher compared to patients who did not have this pathology [11].
In addition to the aforementioned ECG changes, the recently published Brugada syndrome is actively discussed in the literature, which was described 20 years ago as a new syndrome in individuals with a typical electrocardiogram associated with a high risk of atrial fibrillation, sudden cardiac death, mainly in young and healthy men. It is a rare type of arrhythmia, characterized by RBBB and ST segment elevation in the right thoracic leads. This syndrome is accompanied by frequent syncope, but in most cases it is asymptomatic. There are cases when the development of this syndrome was preceded by abundant food intake, rest and sleep, which is explained by the activation of the vagus nerve. The Brugada syndrome is widespread among the countries of Southeast Asia, including Thailand and the Philippines. Some genes are associated with the disease, among which SCN5A is the most frequent [12]. In northern European countries and Japan, as a result of the study of Brugada's syndrome, 8% -10% of patients experience sudden cardiac death due to this syndrome [13,14].
Due to the increased prevalence of hypertension, the frequency of occurrence of LVH has increased, which is predominantly an additional marker for exposure to other risk factors, but it can also directly contribute to worsening CVD due to pathological changes in the cardiac structure. The influence of AD is central to the development of LVH [15]. In a prospective cohort study with a 10-year follow-up in New York, it was found that patients with LVH have a greater risk of developing CVD, compared with those without LVH [16].
Thus, a review of literature data shows that major ECG changes have a significant negative impact on CVD.
References:
1. Peter W. Minnesota coding and the prevalence of ECG abnormalities.J Heart,
2000.
2. Boycov S.A. Epidemiologicheskie metody viyavleniya osnovnix xronicheskix neinfekcionnix zabolevaniy i faktorov riska pri massovix obsledovaniyax naseleniya.//Avtoreferat dissertacii na soiskanie uchenoy stepeni kand.med.nauk //Moskva 2015 r. str.45
3. Sriratanaviriyakul N., et al. Prevalences and association of ECG findings and cardiovascular risk factor in Shinawatra employees. J Med Assoc Thai., 2010.
4. Dunder K., Lind L., et al. A new Q/QS pattern on the resting electrocardiogram is associated with impaired insulin secretion and a poor prognosis in elderly men independently of history of myocardial infarction. J Intern Med., 2004.
5. Horibe H., Kasagi F., et al. A nineteen-year cohort study on the relationship of electrocardiographic findings to all cause mortality among subjects in the national survey on circulatory disorders, NIPPON DATA80. J Epidemiol., 2005.
6. Bussink B.E., Holst A.G., et al.Right bundle branch block: prevalence, risk factors, and outcome in the general population: results from the Copenhagen City Heart Study. Eur Heart J., 2013.
7. Strauss D.G., Loring Z., et al. Right, but not left, bundle branch block is associated with large anteroseptal scar. J Am CollCardiol., 2013.
8. Le VV, Wheeler MT, Mandic S, Dewey F, Fonda H, Perez M, Sungar G, Garza D, Ashley EA, Matheson G, Froelicher V. Addition of the electrocardiogram to the preparticipation examination of college athletes.Clin J Sport Med., 2010.
9. Wongcharoen W, Phrommintikul A, Kanjanavanit R, Amarittakomol A, Topaiboon P, Wiangosot W, Kuanprasert S, Sukonthasarn A. Complete right bundle branch block predicts mortality in Thai patients with chronic heart failure with reduced ejection fraction. J Med Assoc Thai., 2010.
10. Barsheshet A, Goldenberg I, Garty M, Gottlieb S, Sandach A, Laish-Farkash A, Eldar M, Glikson M. Relation of bundle branch block to long-term (four-year) mortality in hospitalized patients with systolic heart failure. Am J Cardiol., 2011.
11. Xiong Y., Wang L., et al. The Prognostic Significance of Right Bundle Branch Block: A Meta-analysis of Prospective Cohort Studies. ClinCardiol., 2015.
12. Brugada R., Campuzano O., et al. Brugada syndrome. Methodist DebakeyCardiovasc J., 2014.
13. Hayashi M., Denjoy I., et al. Incidence and risk factors of arrhythmic events in catecholaminergic polymorphic ventricular tachycardia. Circulation, 2009.
14. Sumitomo N., Harada K., et al. Catecholaminergic polymorphic ventricular tachycardia: electrocardiographic characteristics and optimal therapeutic strategies to prevent sudden death. Heart, 2003.
15. Gosse P. Left ventricular hypertrophy as a predictor of cardiovascular risk. J Hypertens Suppl., 2005.
16. Koren M.J., Devereux R.B., et al. Relation of left ventricular mass and geometry to morbidity and mortality in uncomplicated essential hypertension.Ann Intern Med., 1991.
