Електрокардиографскиот запис како индикатор на степенот на тренираност кај спортисти во Република Македонија: знaчајноста на електрокардиографскиот скрининг во превенцијата и детекција на патолошки промени на срцето кај спортисти

Abstract

Introduction: Professional and amateur sport training could cause a significant burden on the cardiovascular system, which leads to its structural and functional changes, resulting in morphological and electrical heart changes and appearance of “athletes’ heart". It is very important to distinguish these typical training-related changes from the pathological changes which denote presence of mechanical or electrical malformations that could increase the risk of sudden cardiac death (SCD). Following the recommendations for cardiovascular screening in the athletes from the American and European Assosciations, we tried to prove the importance of including the electrocardiogram screening in the athletes in Macedonia. Objectives: To diagnose cardiovascular diseases that could cause a sudden death in athletes; to differentiate between electrocardiographic changes that are due to physiological changes and those that result from pathological changes which lead to refraining from sports; to compare and determine the correlations of ECG changes in relation to: anthropometric and clinical features, sport characteristics, functional parameters before during and/or immediately after exposure to burden and echocardiographic features; to determine the correlation of physiological parameters during an exposure to burden and sports-related characteristics; to determine the predictive factors of ECG changes among the subjects and to establish the criteria for a screening protocol for athletes in the Republic of Macedonia. Data and methods: This prospective cross-sectional study includes 285 subjects (competitive athletes and amateurs) during the period of two years 2016 and 2017. The subjects were 62.1% males and 37.9% females, ages, from 9 to 38 years. All patients were interviewed for sports history, history of cardiovascular symptoms, and family history of cardiovascular diseases. Twelve (12) channel ECGs and Bruce protocol treadmill stress tests were performed in all subjects. 2D transthoracic echocardiography was done in 54 patients with ECG changes. The data was collected in a specific designed data base. Statistical analysis was done by using SPSS Version 22 (IBM SPSS, Inc, Chicago, Illinois). Comparation of the groups was done by ANOVA and/or Person Chi-square test. Pearson and/or Spearman-test was used for the detection of correlation. Multiple linear and binary logistic regression were done for detecting the influence of certain analyzed parameters on ECG changes. Results: Physiologic ECG changes were found in 51.9% of the subjects. The most prevalent were LV hypertrophy (42.2%), ST elevation (43.9%), incomplete RBBB (33.7%), early repolarization (18.6%) and sinus bradycardia (25.3%). In 58.8% of the athletes with indexed LV mass above the normal values ECG signs of LV hypertrophy were detected. There was no significant correlation between ECG changes and echocardiographic signs for LV hypertrophy, but there was a significant correlation with ST segment elevation. The increased Sokolow-Lyon index positively correlated with Q wave in V1-3 wider than 55ms without RBBB, categorized as borderline ECG. There was 1.7 times greater risk of ST segment elevation in cases where the interventricular septum was thicker in the diastole. The risk of ST segment elevation was 1.1 times greater in cases where weekly time of exercise was greater; 1.1 times greater if duration of training in years was greater, and 0.9 times greater if subjects do sports such as soccer, basketball and handball. Borderline ECG changes were found in 21.4% athletes. Binary logistic regression analysis showed delayed S wave upstroke of >55 ms in leads V1–V3 in absence of RBBB, which we classified as borderline ECG where as independent predictors were: increased indexed body area of the increased LV end diastolic volume (EDV/BSA) and abnormal global LV longitudinal systolic deformation (GLS %). Abnormal ECG changes were detected in 22 subjects (7.7%). Negative T wave was most common ECG change, which appeared in 7.4% of the subjects - athletes older than 16 years. There was a significant correlation between abnormal ECG and the length of the training expressed in years, the frequency of training weekly, i.e., the length of sport training during the day expressed in hours. There was a significant correlation between an abnormal ECG and the higher frequiency of training football and basketball. There was a significant correlation of abnormal ECG and rhythm abnormalities during the treadmill stress test, as well. The male athletes with abnormal ECG had the largest mean volume, which were above the referent values. Negative T waves at V1-V3, in athletes older than 16 were statistically significant correlated with lower LCEF, had marginal statistical significance with lower GLS, and were statistically significant correlated with lower DC GLS. The results from this study are in correlation with the published data in the literature, which confirms that athletes with abnormal ECG are candidates for further investigation to determine the etiology of changes, or presence of any structural hеart disease. Conclusion: According to our results, we could conclude that prevalence of ECG changes in the athletes in Macedonia are of high frequency that an obligatory, regular 12 channel ECG in the screening program is required. Annually, a 12 channel ECG during the sport life should be obligatory as well, in order to identify structural hеart diseases, which could be reason for a sudden cardiac death. An athlete with abnormal and possibly marginal estimated ECG should be subjected to a further evaluation with an image method, but the absence of a structural heart disease should not exclude the annual close control of these athletes, especially of their ECG.