Abnormal electrocardiogram findings in athletes

Athletes commonly exhibit a series of electrical, structural, and functional physiological changes which may overlap with cardiac pathology. The last two decades have witnessed a progressive improvement in understanding what can be considered benign for athletes and what may be deemed as potentially pathological and require further investigations. However, diagnostic uncertainties in the cardiac assessment of athletes are often encountered. In particular, the clinical significance of some electrocardiogram (ECG) findings may be uncertain. While uncommon and suggestive of an underlying cardiac condition, they may be identified among healthy athletes without additional pathological findings to support a unifying clinical diagnosis. This creates significant dilemmas for clinicians charged with determining sports eligibility and those who have the responsibility to help athletes in the decision-making process regarding future competitive sports participation. Current guidelines, recommendations, and position papers provide a roadmap for the differential diagnosis between 'athlete's heart' and cardiac disease. However, managing ECG findings of uncertain clinical significance, especially when initial diagnostic evaluation reveals no supportive signs of pathology, has received comparatively less attention, in particular, the type of cardiac investigations, the extent of diagnostic work-up and the need for follow-up require clarification. This document aims to provide guidance based on published evidence and expert opinions to assist in the clinical decision-making regarding ECG anomalies that are common sources of uncertainty when managing asymptomatic athletes.