Association between cardiac dimensions and athlete lineup position: analysis using echocardiography in NCAA football...

In determining what is "abnormal"-in terms of cardiac electrical and morphologic remodeling in athletes-it is important to identify what is "normal" or expected. With specialization for each position in a football team lineup, we attempted to describe the association between the position played and the physiologic cardiac changes of designated players. We evaluated data from 85 National College Athletic Association football players from a single team. The participants were assigned to 1 of 3 groups based on position and training regimen: lineman (n = 34), mobility/power players (n = 13), and skill players (n = 38). Players underwent assessment with electrocardiography and echocardiography (ECHO), with results interpreted by reviewers blinded to players' positions. Linemen were found to have greater body mass index and body surface area (BSA), as well as longer QRS duration (102 ± 10 ms vs 101 ± 7 ms in mobility/power players, and 96 ± 7 ms in skill players; P < 0.007). Left ventricular (LV) voltage values were lower in linemen (27.7 ± 6.5 mV vs 28.8 ± 7 mV in mobility/power players, and 31.8 ± 7.6 mV in skill players; both, P < 0.05). No differences in ejection fraction between groups were revealed on ECHO, but ECHO did show greater calculated LV mass, LV end-diastolic diameter, aortic root diameter, and LV outflow tract diameter in linemen, whether adjusted for BSA or not, and the differences were statistically different. Multivariate analysis showed that position (P < 0.0004 and QRS duration (P = 0.03) predicted LV mass. Echocardiographic variables found to be associated with player position included LV mass adjusted for BSA (P < 0.0001), LV end-diastolic diameter adjusted for BSA (P < 0.0003), and QTc interval (P = 0.007). On multivariate analysis, racial identity did not demonstrate significant differences; however, differences existed on univariate analysis of electrocardiography and ECHO variables, mostly in skill players. In skill players, QRS duration was shorter in the African American (AA) subgroup compared with that in the white/other subgroup. Lateral ST elevation and LV end-systolic volume were greater in AA players after adjustment for BSA, and AA linemen had greater LV posterior wall thickness after adjustment for BSA. In summary, we found that football players who are linemen had greater heart mass than did other players, despite adjustments for body size.