Interpretation of athlete's ECG in a pediatric population using the International Criteria

Abstract Background In Italy, the starting age for pre-participation screening (PPS) is defined by the single sports federations and sometimes includes individuals under the age of 12. Current International Criteria for ECG interpretation in athletes are recommended for subjects between 12 and 35 years of age. Purpose To define the prevalence of ECG alterations (normal, borderline, abnormal) in the ≤12 years population compared to older athletes, and to define which of these are training-related. To assess the applicability of the 2017 International Criteria to a population ≤12 year-old. Methods Athletes of both sexes, aged 7-18 years, undergoing PPS in the period 2019-2022, regardless of the sport discipline, were retrospectively enrolled. The screening protocol for competitive athletes is defined by Italian law. The ECG was interpreted according to the recommendations of the 2017 International Criteria. Results The final population was composed by 2140 athletes (mean age 12.5 ±2.61 years, 60% ≤12 years). No statistically significant differences were found in the percentage of normal (98% vs 97%, p=0.4), borderline (1.8% vs 1.5%, p=0.5) and abnormal (0.5% vs 1.2%, p=0.06) alterations in the group ≤12 years compared to 12 years. The most frequently observed ECG abnormalities were incomplete right bundle branch block (iRBBB, 22.8%), early repolarisation (14.8%) and left ventricular hypertrophy (13.8%). When comparing the two age groups, a statistically significant difference was found in the prevalence of sinus bradycardia (SB, 0.6% vs 8.2%, p0.001), 1st degree atrio-ventricular block (AVB, 0.2% vs 1.6% p0.001) and T-wave inversion in V1-V3 (7.3% vs 2.3%, p0.001) (Figure 1). Furthermore, in the younger age group, there was no correlation between the prevalence of these ECG changes and the level of training. Conclusions SB and 1st degree AVB are extremely rare in athletes ≤12 year-old and do not appear to be training-related, and therefore should be considered as abnormal findings in this population. Furthermore, in both groups, complete RBBB, 2nd degree Mobitz 1 AVB and the presence of one premature ventricular beat on ECG should also be classified as abnormal. The results highlight the limitations of using International Criteria for the interpretation of the athlete's ECG in young people under 18 years, and particularly under 12. Figure 1