Background Intense physical exercise is associated with modest increases in left ventricular wall thickness (LVWT) and cavity size. The magnitude of increase in cardiac dimensions is affected by various demographic factors including age, gender, size and type of sport. Studies confined to male athletes indicate that athletes of African/Caribbean (black; BA) origin develop left ventricular hypertrophy of greater magnitude than Caucasian (white; WA) athletes of similar age and size that participate in identical sporting disciplines. The impact of ethnicity has not been studied in female athletes. The aim of this echocardiographic study was to compare left ventricular cardiac dimensions in female WA and BA.
Methods Between 2006 and 2008, 110 nationally ranked female BA and 193 WA of similar age (BA 21 ± 4.62 years (range 14–35) vs WA 20 ± 4.03 years (range 14–35), p = 0.18), size (body surface area (BSA); BA 1.78 ±0.17 kg/m2 (range 1.31–2.21) vs WA 1.73 ± 0.18 kg/m2 (range 1.33–1.96), p = 0.10) and participating in a range of ball, racket and endurance sporting disciplines underwent 2-D echocardiography using a GE Vivid I. Standard views and measurements were performed by an experienced sport cardiologist. LVWT was measured from the septum and the left ventricular posterior wall; the greatest measurement was defined as the maximal LVWT. Left ventricular mass (LVM) was calculated using the formula of Devereuax.
Results Black athletes demonstrated significantly greater maximal LVWT compared with white athletes (9.2 ± 1.1 mm (range 6–13 mm) vs 8.7 ± 1.05 mm (range 6–11), p<0.001) amounting to a 7% difference in maximal LVWT. BA exhibited a greater left atrial diameter compared with WA (35.6 ± 4.2 mm (range 21–41) vs 32.4 ± 4.79 mm (range 25–47), p<0.001). LVM was also significantly greater in BA versus WA (169 ± 37 g (range 95–210) vs 159 ± 36 g (range 86–212), p<0.001). There were no differences between the two ethnic groups with respect to the left ventricular end diastolic cavity size (BA 48.3 ± 3.9 mm (range 39–58) vs WA 47.8 ± 4.3 mm (range 40–62), p = 0.95), or aortic root diameter (BA 27.1 ± 2.9 mm (range 23–38) vs WA 26.4 ± 2.8 mm (range 17–33), p = 0.28). In contrast with previously published literature in WA, two (0.6%) female BA (but none of the female WA) exhibited a maximal LVWT of 12 mm or more.
Conclusion Black female athletes exhibit a greater maximal LVWT and LVM compared with white female athletes of similar age and size participating in identical sporting disciplines. The precise mechanism for exaggerated hypertrophic response in black athletes in response to the increased preload and after load associated with exercise in BA remains to be elucidated.