What causes ST elevations in a normal adolescent?

ST Elevations in Normal Adolescents: Causes and Significance

ST elevation in normal adolescents is most commonly due to early repolarization, which is a benign normal variant that does not require further evaluation in the absence of symptoms, signs, or family history of cardiac disease. 1

Normal Variants Causing ST Elevation in Adolescents

• Early repolarization - Characterized by J-point elevation, ST-segment elevation, J waves, or terminal QRS slurring in the inferior and/or lateral leads; this is a normal training-related ECG alteration in athletes and a physiologic adaptation to regular exercise 1

• Juvenile T-wave pattern - T-wave inversion in leads V2-V3 in adolescents under 16 years of age; present in 10-15% of white adolescent athletes aged 12 years but only in 2.5% of white athletes aged 14-15 years 1

• Black athlete repolarization variant - J-point elevation and convex ('domed') ST-segment elevation followed by T-wave inversion in leads V2-V4 in black athletes 1

Age-Related Considerations

• The "juvenile ECG pattern" is a normal age-related finding in adolescents up to 16 years of age, characterized by T-wave inversion or biphasic T-waves beyond lead V2 1

• Anterior T-wave inversion that extends beyond lead V2 is rare (0.1%) in white athletes ≥16 years or younger athletes who have completed puberty 1

• Normal T-wave patterns in adolescents older than 1 month include T-wave inversion in leads V1, V2, and V3 1

• In adolescents 12 years and older and young adults less than 20 years, the T wave may be slightly inverted in aVF and inverted in lead V1 1

Distinguishing Normal from Pathological ST Elevation

Normal ST Elevation Characteristics:

• J-point elevation in V2 varies by age, gender, and ethnicity:
  • Upper normal limit for white men <40 years: approximately 0.3 mV (up to 0.33 mV in 24-29 year age group) 1
  • Upper normal limit for white women: approximately 0.15 mV (relatively unchanged with age) 1
  • Upper normal limit for black men: approximately 0.20 mV 1
  • Upper normal limit for black women: approximately 0.15 mV 1

Pathological ST Elevation to Consider:

• Brugada Type 1 pattern - Coved pattern with initial ST-segment elevation ≥2 mm with downsloping ST-segment elevation followed by a negative symmetric T-wave in ≥1 leads in V1-V3 1

• Acute myocardial ischemia/infarction - While rare in adolescents, it should be considered when ST elevation exceeds threshold values (0.25 mV for men <40 years, 0.15 mV for women in V2-V3) 1, 2

• Pericarditis - Diffuse ST elevation in multiple leads with PR segment depression 3

Clinical Approach to ST Elevation in Adolescents

1. Determine if ST elevation is within normal limits for age, gender, and ethnicity 1

2. Look for associated ECG findings that might suggest pathology:

   • Ventricular pre-excitation (PR interval <120 ms with delta wave) 1
   • Prolonged QT interval 1
   • Atrial or ventricular arrhythmias 1

3. Consider clinical context:

   • Asymptomatic adolescents with isolated ST elevation consistent with early repolarization do not require further evaluation 1, 4
   • ST elevation is not associated with cardiac death in clinical populations or with cardiac events in athletes 4

4. Red flags requiring further evaluation:

   • ST elevation >0.2 mV (2 mm) is very unusual and may warrant further investigation 4
   • Presence of chest pain or other cardiac symptoms 2
   • Family history of sudden cardiac death or inherited cardiac conditions 1
   • ST elevation accompanied by two or more borderline ECG findings 1

Caveat

Early repolarization patterns in adolescents can sometimes be confused with more serious conditions like Brugada syndrome or acute coronary syndromes 5, 3. The key distinguishing features include the pattern and distribution of ST elevation, associated symptoms, and family history. When in doubt, further cardiac evaluation may be warranted, particularly if there are concerning symptoms or family history.