Is an individual with early repolarization and an ascending ST segment electrocardiogram (ECG) finding physically fit to participate in a 5 km race?

Early Repolarization with Ascending ST Segment: Fitness for 5 km Race

Yes, an individual with early repolarization and an ascending (upsloping) ST segment is physically fit to participate in a 5 km race without any additional cardiac evaluation, provided they are asymptomatic and have no concerning personal or family history. 1, 2

Why This Pattern is Benign

Early repolarization with an ascending/upsloping ST segment is an extremely common physiological finding that occurs in 50-80% of trained athletes and represents normal cardiac adaptation, not pathology. 1, 2 The key diagnostic features that confirm this is benign include:

• J-point elevation ≥0.1 mV with upward concave (ascending) ST-segment morphology 1
• **STJ/ST80 ratio <1**, which definitively distinguishes benign early repolarization from dangerous Brugada syndrome (where the ratio is >1) 3, 2
• Concordant tall, peaked T-waves following the ST elevation 1
• Most commonly affects inferior (II, III, aVF) and/or lateral leads (I, aVL, V4-V6) 1

Clearance Algorithm

The individual can be immediately cleared for the 5 km race if ALL of the following are true:

• No personal history of syncope, seizures, cardiac arrest, palpitations, or exercise-related chest pain 2
• No family history of sudden cardiac death before age 50 years 2
• The ST segment is upsloping/concave upward (not downsloping or coved) 1, 2
• The pattern normalizes with exercise or adrenergic stimulation 1

No further cardiac testing, echocardiography, or specialist referral is required when these criteria are met. 1, 3, 2

Red Flags That Would Require Cardiology Referral

The following findings would mandate stopping participation and obtaining cardiology evaluation before clearance:

• STJ/ST80 ratio >1 (suggests Brugada syndrome, not benign early repolarization) 3, 2
• Downsloping or coved ST-segment morphology 2
• History of unexplained syncope, seizures, or cardiac arrest 2
• Family history of sudden cardiac death <50 years 2
• Exercise-induced symptoms (chest pain, palpitations, presyncope during exertion) 2

Critical Distinction: Benign vs. Dangerous Patterns

The ascending ST segment is the key protective feature. The American College of Cardiology guidelines emphasize that the Corrado index (STJ/ST80 ratio) has 97% sensitivity and 100% specificity for distinguishing benign early repolarization from Brugada Type 1 pattern. 4, 2

• Benign early repolarization: Upsloping ST with STJ/ST80 <1 4
• Brugada syndrome: Downsloping ST with STJ/ST80 >1, requiring immediate electrophysiology referral 4

Evidence Quality

The 2017 International Recommendations for Electrocardiographic Interpretation in Athletes (Journal of the American College of Cardiology) provides the highest quality evidence, reclassifying early repolarization from "abnormal" to "physiological and training-related" in athletes, reducing false-positive rates by 70%. 2 This guideline explicitly states that all patterns of early repolarization, when present in isolation without clinical markers of pathology, should be considered benign variants requiring no further evaluation. 1

Common Pitfall to Avoid

Do not confuse benign early repolarization with acute myocardial infarction or pericarditis in the emergency setting. 1, 5 The ascending/concave morphology, peaked T-waves, and normalization with exercise distinguish this benign variant from pathological ST elevation. 4, 1 Exercise actually normalizes the J-point elevation in early repolarization—this is a normal finding. 4