Sex-related differences in left ventricular structure in early adolescent non-professional athletes

BACKGROUND: Professional athletes exhibit lower left ventricular wall thicknesses, diameters and mass (in females), with less frequent training-related electrocardiogram (ECG) changes, as compared with controls. METHODS: We studied the association of sex with left ventricular structure in trained early adolescents. Two hundred and six adolescent Caucasian athletes (mean age 13.8 ± 1.6, range 11.8-16.9 years, 158 males and 48 females), with similar degree of training underwent ECG and echocardiographic measurements of left ventricular diameters, thicknesses and mass, with relative wall thickness as the remodelling index. RESULTS: As compared with females, males exhibited greater maximal wall thickness (males = 8.7 ± 1.2 vs. females = 7.9 ± 0.8) and indexed left ventricular mass (100 ± 18 g/m2 vs. 79 ± 12, p < 0.001), without differences in relative wall thickness (males = 0.35 ± 0.04 vs. females = 0.34 ± 0.04) and with higher prevalence of ECG-based left ventricular hypertrophy, sinus bradycardia and ST-elevation. An analysis of covariance, using age, body surface area, systolic blood pressure, heart rate and sex as the covariates, reported that sex is a strong predictor of left ventricular mass, maximal wall thickness, left ventricular diastolic diameter and ECG-based left ventricular hypertrophy. In a binary logistic regression model analysis sex, like left ventricular mass, predicted ST-trait elevation. CONCLUSIONS: Our results suggest that, in early adolescence, female athletes have lower left ventricular mass and thicknesses compared with males, without geometrical differences. Therefore, sex, independent of age, is a strong determinant of structural parameters also in early adolescent athletes. These data indicate that sex-specific parameters are needed in the pre-participation cardiovascular screening of adolescent athletes.