Fine Tuning ECG Interpretation for Young Athletes: ECG Screening Using Z-score-based Analysis

Area of Science:

• Cardiology
• Sports Medicine
• Biostatistics

Background:

• Physiologic adaptations to exercise on electrocardiograms (ECGs) in athletes can mimic cardiovascular abnormalities.
• Current ECG criteria for athletes lack correlation with disease states and comparison data.
• A need exists to differentiate exercise-induced ECG changes from underlying pathology in athletes.

Purpose of the Study:

• To compare ECGs of collegiate athletes and non-athlete controls using Z-scores.
• To identify significant differences in digital ECG variables between athletes and controls.
• To evaluate ECG variables in athletes that fall outside the normal range.

Main Methods:

• Retrospective review of 102 digital ECG variables from 7206 subjects (17-22 years), including 672 athletes.
• Derivation of age and sex-specific Z-scores from a normal population dataset.
• Assessment of ECG variable ranges in young athletes using Z-scores.

Main Results:

• Athletes exhibited distinct ECG patterns: slower heart rate, longer PR interval, altered QRS axis and duration, shorter QTc, larger T waves, prevalent R' waves, and higher voltage criteria for left ventricular hypertrophy (LVH).
• Most athletes (83%) had Z-scores within -2.5 to 2.5; 8.9% had Z-scores outside -3 to 3.
• While 28.4% met traditional LVH voltage criteria, only 7.9% had Z-scores outside -2.5 to 2.5 for key LVH indicators; only one athlete was diagnosed with hypertrophic cardiomyopathy.

Conclusions:

• Z-scores derived from a normal population offer precise screening for cardiac abnormalities in young athletes.
• This approach can minimize unnecessary secondary testing, restrictions, and anxiety.
• Z-scores enhance the ability to distinguish normal athletic adaptations from true pathology on ECGs.