Abstract 878: Normal Distribution of Left Ventricular Wall Thickness in Highly Trained Black Athletes
Regular physical training is associated with moderate increases in left ventricular wall thickness (LVWT). Recent small studies have indicated that male athletes of Afro-Caribbean (black BA) origin may develop a greater magnitude of left ventricular hypertrophy (LVH) compared to similar white athletes (WA), and some exhibit LV wall measurements that overlap with morphologically mild hypertrophic cardiomyopathy (HCM). The physiological upper limits for LVWT are unknown in BAs, increasing the chance of an erroneous diagnosis of HCM. The aim of this echocardiographic study was to establish the normal range for measures of LVWT in a large group of highly trained male black athletes.
Methods Between 2004 and 2009, 1295 national level male athletes (573 44% black) of similar age, size, and sporting discipline, underwent 2-D echocardiography as part of a pre-participation screening program. LV measurements were collected according to standard protocols, with left ventricular mass calculated using the formula of Devereuax. All athletes with a maximum LVWT of >12mm underwent appropriate investigations to exclude phenotypic features of HCM.
Results Black athletes exhibited a significantly greater maximal LVWT (10.6+/− 1.6mm (range 7–19) vs. 10.0+/−1.1 mm (range 6 –14) P<0.001), and LV mass (208+/−52g (range 93– 496) vs.197+/−45g (range 90 –376) P>0.001), compared to WA’s. In total, 72 BA’s (12.5%) exhibited a maximal LVWT of >12mm, compared to only 12 (1.6%) WA (p<0.001). No WA had a maximal LVWT of >15mm, compared to 3 (0.5%) BAs, P<0.001. All black athletes with an LV >13mm had a normal LV cavity size (52.6mm+/−4.6 (range 44 – 61mm), left atrial diameter (36.2mm+/−5.8 (range 30 – 44)), and aortic root diameter (31.4 +/−4.8mm (range 26 –35)) with normal indices of diastolic function (E/A ratio 2.15+/− 0.9). No athlete demonstrated any further phenotypic features of HCM
Conclusion Male black athletes develop a greater magnitude of physiological LVH when compared to similar white athletes. A significantly greater number of BA exhibit values of maximal LVWT that are in the range seen in HCM. The data presented, derived from a large group of highly trained individuals suggests that 14mm should be the upper limit of physiological LVH in male BA, but should remain at 12mm for WA