From the Guidelines
ECG interpretation in athletes should prioritize distinguishing normal training-related changes from pathological findings, using the most recent guidelines such as the International Recommendations for Electrocardiographic Interpretation in Athletes 1. When interpreting an athlete's ECG, normal athletic adaptations include sinus bradycardia (heart rate 30-60 bpm), first-degree AV block, incomplete right bundle branch block, early repolarization, and isolated QRS voltage criteria for left ventricular hypertrophy. Concerning abnormal findings that warrant further investigation include:
- T-wave inversion beyond V1
- ST-segment depression
- Pathological Q waves
- Left bundle branch block
- QRS duration >140ms
- Ventricular pre-excitation
- Prolonged QT interval (>470ms in males, >480ms in females)
- Brugada-like patterns These findings should be evaluated in the context of the athlete's age, ethnicity, sport type, and training intensity, as certain findings like T-wave inversion in V1-V4 may be normal in Black athletes 1. The International Criteria provide a standardized framework for interpretation, and athletes with abnormal ECG findings should undergo comprehensive evaluation including echocardiography, exercise testing, cardiac MRI, or genetic testing as appropriate before clearance for competition. Regular ECG screening is particularly important for high-intensity competitive athletes to identify conditions like hypertrophic cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy, and channelopathies that could increase the risk of sudden cardiac death.
From the Research
ECG Interpretation Guidelines for Athletes
The following guidelines are based on the International Criteria for ECG interpretation in athletes, which aim to distinguish physiologic from pathologic ECG findings in athletes 2, 3, 4.
- Common ECG findings in athletes:
- Sinus bradycardia is the most frequent adaptation 5
- Non-specific intraventricular conduction delay and incomplete right bundle branch block are also frequent 5
- High QRS voltage is more frequent in male athletes, but its correlation with left ventricular hypertrophy is low 5
- ST segment elevation in the "early repolarization" pattern is typical of the athlete's electrocardiogram 5
- Challenges in ECG diagnosis:
- Incomplete right bundle branch block (IRBBB) can express both benign and pathological patterns 6
- IRBBB is a common ECG finding at all ages, more frequent in men and athletes 6
- It is necessary to differentiate IRBBB from pathological patterns such as type-2 Brugada ECG pattern, right ventricular enlargement, arrhythmogenic right ventricular cardiomyopathy, ventricular preexcitation—Wolf-Parkinson-White syndrome, and hyperkalemia 6
- Importance of physician education:
- A critical need exists for physician education in modern ECG interpretation that distinguishes normal physiological adaptations in athletes from distinctly abnormal findings suggestive of underlying pathology 3, 4
- Physicians responsible for the cardiovascular care of athletes should be knowledgeable and competent in ECG interpretation in athletes 3, 4