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Background QRS fragmentation (fQRS) and low QRS voltage are ECG findings associated with cardiomyopathy and adverse cardiac events. However, their prevalence and significance in elite female athletes, who exhibit unique patterns of cardiac remodelling, are unknown.Methods Between April 2017 and October 2024, 2,566 consecutive elite female football players underwent pre-participation cardiovascular screening with a health questionnaire, physical examination, 12-lead ECG and transthoracic echocardiogram. ECGs were retrospectively reviewed for fQRS (≥1 additional notch or R′ in the QRS complex) and low QRS voltage in all limb leads (<0.5 mV). Players who demonstrated incomplete right bundle branch block (RBBB) or RBBB were not defined as fQRS, unless fQRS was exhibited in leads other than leads V 1 and V2. Findings were correlated with demographic and echocardiographic data, and athletes with suspected pathology underwent further investigation. The mean follow-up period was 4.4±2.5 years.Results The mean age was 20.13 ± 5.48 years. Any fQRS in at least one lead was present in 732 (28.5%) athletes, most commonly in lead V1. fQRS in lead V1 alone occurred in 370 (14.4%), and fQRS in ≥2 contiguous leads in 205 (8.0%), predominantly in the anterior territory (61.3%). Athletes with fQRS in ≥2 contiguous leads had an increased basal right ventricular and indexed end-diastolic LV diameter compared with those without fQRS (35.4 ± 3.1 vs 34.2 ± 3.8 mm; p<0.001, 28.2 ± 2.7 vs 27.8 ± 2.4 mm/m 2; p=0.033 respectively). Low QRS voltage in the limb leads was exceedingly rare, observed in only 2 (0.1%) athletes. No athlete with fQRS or low QRS voltage was diagnosed with cardiomyopathy at screening. Four (2.0%) athletes with fQRS≥2 contiguous leads were diagnosed with minor cardiac pathology, including one with non-significant atrial septal defect and three with moderate degree of valvular regurgitation. None of the four athletes with minor cardiac conditions demonstrated associated abnormal ECG findings. During the follow-up period of 4.4 ± 2.5 years, no players with or without fQRS in ≥2 contiguous leads experienced sudden cardiac arrest or death.Conclusion In elite female football players, fQRS is a common ECG finding strongly associated with physiological biventricular remodelling, particularly of the right ventricle. fQRS likely represents a benign feature of the athlete’s heart rather than underlying pathology. Conversely, the extreme rarity of low QRS voltage suggests it warrants clinical suspicion if detected. These sex-specific findings provide a new reference for interpreting ECGs in this unique population.Acknowledgement We thank the English Football Association Cardiac Advisory Group for their input.