Aims Low QRS voltages (LQRSV) in limb leads and QRS fragmentation (FQRS) are possible
electrocardiographic signs of myocardial fibrosis and cardiomyopathy, but they are
not listed in current criteria for interpreting athlete's electrocardiogram (ECG).
We investigated the prevalence and determinants of LQRSV and FQRS in a cohort of young
apparently healthy athletes undergoing pre-participation screening (PPS). Methods
and results We analysed a consecutive series of 2140 ECG obtained during PPS of young
athletes (mean age 12.5 +/- 2.6 years, 7-18-year-old, 49% males). The peak-to-peak
QRS voltage was measured in all limb leads, and LQRSV were defined when maximum value
was <0.5 mV. Fragmented QRS morphologies were grouped into five patterns. Lead aVR
was not considered. Maximum peak-to-peak QRS voltage in limb leads was 1.4 +/- 0.4
mV, similar between younger and older athletes, but significantly lower in females
than males (1.35 +/- 0.38 mV vs. 1.45 +/- 0.42 mV; P < 0.001). There was a weak correlation
between maximal QRS voltages and body mass index (BMI), but not with type of sport
or training load. Only five (0.2%) individuals showed LQRSV. At least one fragmented
QRS complex was identified in 831 (39%) individuals but excluding the rSr ' pattern
in V1-V2, only 10 (0.5%) showed FQRS in >= 2 contiguous leads. They were older than
those without FQRS, but did not differ in terms of gender, BMI, type of sport, or
training load. Conclusion Low QRS voltages in limb leads and FQRS in >= 2 contiguous
leads excluding V1-V2 are rare in young apparently healthy athletes and are not related
to the type and intensity of sport activity. Therefore, they may require additional
testing to rule out an underlying disease particularly when other abnormalities are
present. Lay summary Low QRS voltages (LQRSV) in limb leads and QRS fragmentation
(FQRS) are possible electrocardiographic signs of myocardial fibrosis and cardiomyopathy.
In our study, we analysed the occurrence and characteristics of FQRS and LQRSV in
young athletes undergoing pre-participation screening. We found a low prevalence of
these abnormalities, with only 0.2% showing LQRSV and 0.5% displaying FQRS.These abnormalities
were not associated with factors such as gender, age, type of sport, or training load.
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