Ecg findings in athletes: interpretation according to seattle criteria and international criteria (2017). correlation of ecg findings with sports type, exercise intensity, training volume and fitness level

Introduction: Sudden cardiac death is one of the leading causes of death in athletes during sports participation. Pre-participation examination aims to prevent sudden cardiac death of athletes. Electrocardiogram (ECG) is used in the screening process due to the presence of pathologic ECG findings in the majority of athletes with cardiac pathology. In order to facilitate recognition of cardiac pathologies in sports and to limit false positive results, ECG interpretation criteria have been established and developed over the last 10 years. ESC Criteria were published in 2005 and 2010. Subsequently, the Seattle Criteria were published in 2013 and the reference values of the pathological ECG findings included in the ESC 2010 criteria were described in detail. Finally, International Criteria was published which establishes a clear and practical findings list including normal, borderline and pathological ECG findings in 2017. In recent years, in order to assist physicians, computer softwares have been developed to detect abnormal ECG findings in athletes by processing the data obtained from the ECG. The frequency, shape and grade of ECG changes in athletes are related to factors such as age, gender, type of sports, intensity of exercise and level of physical fitness. Exercise-related benign ECG findings are more frequent in endurance sports, male gender, some sports branches such as basketball, and those who exercise at high intensity. However, the relationship between pathologic ECG findings and athletes with different sports types, intensity of exercise, physical fitness level and training level has not been well established. Most of the current studies on ECG changes in athletes were conducted before the emergence of ECG interpretation criteria. In those studies sports disciplines had been compared to each other without considering the dynamic and static components of sports branches. In addition, in the previous studies, the training period and physical fitness level parameters of the athletes were mostly ignored. There are no studies in the literature that analyze the relationship between ECG findings and sports type, exercise intensity, physical fitness level and training level parameters by interpreting ECG changes in athletes according to International Criteria. Aim: Our primary aim is to evaluate ECG findings of the athletes according to Seattle Criteria and International Criteria (2017) and to investigate the association between ECG findings of the athletes and parameters such as gender, sports type, exercise intensity, training volume, physical fitness level. Secondary aims are to determine if a computer software integrated into the ECG device at the pre-participation examination is as consistent as an experienced physician in evaluating the ECG findings and thus have an idea about the clinical availability of such a technology and to examine the pre-participation examination attitudes applied to the athlete; to figure out the accuracy of the pre-participation examination in the health units; to investigate the presence of cases that were not redirected to further examination despite presence of pathologic ECG findings. Method: In the analysis of the ECG findings, Cardiopoint Software SDS (Sudden Death Screening) Module (BTL, UK) integrated into the ECG device was used. ECG findings were evaluated by two cardiologists independent of each other according to Seattle Criteria and International Criteria. The ECG findings were examined in terms of the consistency of the evaluations of cardiologists and the Cardiopoint Software SDS Module. Three-minute step test was performed to determine the physical fitness level of the athletes. The athlete's training volume was determined via debriefing athlete's sports history. Sports type and exercise intensity of sports branches were determined using Modified Mitchell classification. Arterial blood pressure (BP) measurement was performed on both arms. The relationship between these parameters and normal, borderline and abnormal ECG findings was examined. Statistical Analysis: Statistical analysis was performed with SPSS version 22.0 (SPSS® Inc, Chicago, IL, USA). Descriptive minimum, maximum, mean and standard deviation (SD) values were calculated for continuous variables. Frequency values were calculated for proportional data. Fisher's exact test was used to examine association between demographic findings and sports features with ECG findings. The kappa consistency test was performed to compare ECG evaluations of cardiologists and CardioPoint Software SDS Module. The Mann Whitney-U test was performed to compare the continuous measures of athletes with pathological, borderline and normal ECG findings and those without ECG findings. Pearson correlation test was used to examine correlation of continuous measurements. For all comparisons, a p value of <0.05 was considered statistically significant. Results: In this study, ECG findings were obtained from 303 athletes with 113 women (37,3%) and 190 men (62,7%) from 34 different branches between the ages of 13-36 years who were taken to pre-participation examination during the last year. ECG findings were evaluated with Cardiopoint Software SDS Module. Right atrial enlargement, which is a borderline ECG finding, incomplete right bundle branch block (RBBB), early repolarization and sinus bradycardia, which are normal ECG findings, were found to be more frequent in endurance-athletes than strength-athletes (p<0,05). Isolated QRS voltage criteria for left ventricular hypertrophy (LVH), early repolarization, sinus bradycardia, respiratory sinus arrhythmia, which are normal ECG findings, were more frequent in those who exercise at high intensity than those who exercise at low to moderate intensity (p<0,05). Isolated QRS voltage criteria for LVH and early repolarization were more common in male gender, while juvenile T wave pattern was more common in female gender (p<0,05). In athletes performing sports that contain high dynamic-high static component (IIIC), chest pain history was 3.3 times, syncope / pre-syncope history was 5 times higher than the other athletes (p<0,05). The physical fitness level of athletes performing endurance sports was better than that of athletes performing strength sports (p<0,05). Body mass index (BMI) correlated positively with systolic BP (p < 0,05, r = 0,351) and diastolic BP (p<0,05, r = 0,257). Blood pressure elevation was more frequent in male gender, in high intensity exercisers and in athletes performing strength sports (p<0,05). Consistency of Cardiopoint Software SDS Module and cardiologist was moderate (0,41-0,59) on the Seattle Criteria and strong (0,42-0,63) on the International Criteria. In the pre-participation examinations done in the health units, detailed anamnesis was taken from 45.2% of all athletes, ECG was performed to 40.3% of all athletes. In pre-participation examinations done in health units, the number of cases in which pathological ECG findings could not be detected even though they were present was 6 (1.8%). These cases had been evaluated by family physicians (57.1%) and state hospitals (42.9%), whose rates of taking anamnesis and ECG evaluation were found low. Conclusion: This study is the first study evaluating ECG findings according to International Criteria in Turkish athlete population and examining the relationship between these findings and training and sports discipline characteristics. The relationship between gender, sports type, exercise intensity, training volume, physical fitness level parameters and presence of pathological ECG findings is not significant. Benign ECG findings are more frequent in endurance athletes, in those who exercise at high intensity, and at those with good physical fitness. As the intensity of exercise increases, the incidence of symptoms in the athletes increases. Blood pressure elevation is more frequent in male athletes, in high-intensity exercises and strength athletes. When ECG findings of the athletes are being evaluated, the characteristics of the sports branch should be considered. All physicians who examine athletes before participation in sports should be well informed about the practices of pre-participation examination. Cardiopoint Software SDS Module evaluation and the physician evaluation have similar consistency and Cardiopoint Software SDS Module needs to be rearranged according to the International Criteria. The use of this technology can help to save time, to ensure standardization of ECG evaluation in health units, and therefore to prevent missing the cases under risk of SCD.