Physiologic limits of left ventricular hypertrophy in elite junior athletes: Relevance to differential diagnosis of athlete's heart and hypertrophic cardiomyopathy

OBJECTIVES The present study was undertaken to define physiologic limits of left ventricular hypertrophy in elite adolescent athletes. BACKGROUND Systematic sports training may cause increased left ventricular wall thickness (LVWT), creating uncertainty regarding the differential diagnosis of athlete's heart from hypertrophic cardiomyopathy (HCM). This distinction is crucial because HCM is responsible for about one-third of all sudden deaths in young athletes. Echocardiographic data defining athlete's heart are limited largely to adults, with little information specifically in adolescent athletes (14 to 18 years old), for whom the risk of sudden death from HCM is highest. METHODS Seven hundred and twenty elite adolescent athletes (75% male) aged 15.7 +/- 1.4 years participating in hall, racket, and endurance sports and 250 healthy sedentary controls of similar age, gender, and body surface area underwent echocardiography. RESULTS Compared with controls, athletes had greater absolute LVWT (9.5 +/- 1.7 mm vs. 8.4 +/- 1.4 mm; p < 0.0001). Maximal LVMT exceeded predicted upper limits in 38 athletes (5%); however, no female athlete had a LVMT >11 mm and only three trained male athletes had absolute LVWT >12 mm (0.4%). Each of the 38 athletes with a LVWT exceeding predicted limits also showed enlarged left ventricular cavity dimension (54.4 +/- 2.1 mm; range 52 to 60 mm). CONCLUSIONS Trained adolescent athletes demonstrated greater absolute LVWT compared with nonathletes. Only a small proportion of athletes exhibited a LVWT exceeding upper limits, very rarely >12 mm, and then always with chamber enlargement. Hypertrophic cardiomyopathy should be considered strongly in any trained adolescent male athlete with LVWT >12 mm (females >11 mm) and nondilated left ventricle. (J Am Coll Cardiol 2002;40:1431-6). (C) 2002 by the American College of Cardiology Foundation.