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By Ken Grauer, MD
Figure. A 12-lead ECG obtained from a 21-year-old athlete.
Clinical Scenario: The 12-lead ECG shown in the Figure was obtained from a 21-year-old endurance-sport male athlete. What important cardiac abnormality might be present? What else might this ECG be reflective of?
Interpretation: The ECG in the Figure is not a normal tracing. There is sinus bradycardia and arrhythmia, normal intervals (PR, QRS, and QT), and a vertical though still normal mean QRS axis of approximately +90°. The findings of concern are several: 1) moderately deep (though narrow) Q waves in multiple leads (II, III, aVF, V3-V6); 2) markedly increased QRS amplitude (deep S waves in leads V1-V2, and early transition with tall R waves in leads V2-V4); and 3) the suggestion of prominent septal forces (tall R wave = S in lead V1, early transition, and the inferolateral Q waves just noted). In addition, there are some ST-T wave changes consistent with an early repolarization pattern (slight J point ST segment elevation in the inferolateral leads, and ST segment coving in leads V1-V4).
ECG abnormalities are commonly seen in otherwise healthy young adults. This is especially true in athletes. A recent study by Pelliccia and colleagues is particularly insightful with regard to the incidence of ECG abnormalities in young adult athletes and the clinical relevance of the abnormalities found (Pelliccia A, et al. Circulation. 2000; 102:278-284). Among a series of more than 1000 consecutive young Italian men and women participating in 38 different sporting activities, 60% had a normal or near normal tracing (early repolarization, 1° AV block and incomplete right bundle branch block were all considered near normal and acceptable normal variants in these otherwise healthy young adult athletes). Forty percent of the overall group had at least mild-to-moderate ECG abnormalities, of which approximately one third had distinctly abnormal tracings. Marked abnormalities were significantly more common in male athletes, athletes younger than 20 years of age, and in those participating in endurance sports (rowing, cycling, cross-country skiing, or long-distance running). Surprisingly, despite even striking ECG abnormalities, structural abnormality (beyond modest physiologic increase in selected cardiac dimensions on echocardiography) was uncommon. The "good" news derived from this study is that the ECG finding of a normal ECG in a young competitive athlete is highly predictive of a normal heart. The problematic result is that as many as 15% of young adult athletes (especially those involved in endurance sports) may have a markedly abnormal ECG, such as the one shown in the Figure. While echocardiography is appropriate (to rule out hypertrophic cardiomyopathy) in individuals such as the 21-year-old athlete in this case, the overwhelming majority of young competitive athletes with distinctly "abnormal" ECGs will end up having a structurally normal heart.
Dr. Grauer, Professor, Assistant Director, Family Practice Residency Program, University of Florida, ACLS Affiliate Faculty for Florida, is Associate Editor of Internal Medicine Alert.