Exploring low QRS voltages and QRS fragmentation in pediatric and adolescent athletes: prevalence and determinants factors

Background Low QRS Voltages (LQRSV) in limb leads and QRS fragmentation (FQRS) are possible signs of myocardial fibrosis and cardiomyopathy, but they are not mentioned in the 2017 International Criteria for the interpretation of athlete’s ECG. Purpose We aimed to investigate the determinants of LQRSV and FQRS in a cohort of young apparently healthy athletes undergoing preparticipation screening (PPS). Methods We analysed a consecutive series of ECG recorded at the time of PPS of young athletes aged 7-18 years. The maximal peak-to-peak QRS voltage was considered and LQRSV was defined when all limb leads have a voltage <0.5 mV. Fragmented QRS morphologies were coded and detected in each individual lead and then grouped into five patterns. Lead aVR was not considered. Results We included 2140 children-athletes (mean age 12.5±2.6 years, 48% males) with no overt cardiac diseases. Mean QRS voltage in limb leads was 1.4±0.4 mV, similar between males and females and between younger and older athletes (Figure 1). The correlation between maximal QRS voltages and BMI or exercise intensity was weak. Only 5 (0.2%) children-athletes showed LQRSV. At least one fragmented QRS complex was identified in 831 (39%) of children-athletes, particularly in leads V1 (24%), V2 (12%) and aVL (16%) (Figure 2). If children-athletes with a rSr’ pattern in V1-V2 were excluded, only 10 (0.5%) showed FQRS in ≥2 contiguous leads. These 10 children-athletes were older than those without FQRS, but did not differ in terms of sex, BMI or exercise-intensity. Conclusions LQRSV in limb leads and FQRSV in ≥2 contiguous leads excluding V1-V2 are rare in children-athletes undergoing PPS of both sexes and are not training-related: for this reason, they may require additional testing to rule out an underlying disease.