Table 2 The multi-factorial nature of the athlete heart—points for considerations

Sporting type

Endurance athletes often present with physiological eccentric hypertrophy of the LV; however concentric remodelling in any athlete is rare

Endurance athletes typically present normal or decreased systolic function and normal or superior diastolic function compared with the non-athletic population

Athletes engaging in endurance disciplines may present with bi-atrial dilatation which is strongly correlated with exercise capacity

Endurance and resistance trained athletes tend to present larger aortic root size than the non-athletic population. However, these differences in size are not clinically significant and therefore the presence of a dilated aortic root warrants further investigation

Ethnicity

There is a greater prevalence of LVH in black athletes compared to white, Asian, Arab, Pacific Islander and mixed ethnicity athletes

Mixed ethnicity athletes of black lineage have phenotypical similarities to black athletes although less pronounced and have a greater LV wall thickness than white athletes

Male black athletes may have a RWT of up to 0.51 or 0.48 in female black athletes, but this finding should be interpreted with caution in the presence of symptoms or a family history of SCD, or an abnormal 12-lead ECG demonstrating, for example, lateral T wave inversion

RV structural adaptation is similar across ethnicities

Black athletes appear to have larger LA dimensions than white athletes but until this has been reproduced in future studies the existing normal ranges should be applied

Body size

Indexing LV end diastolic diameter and LV mass to fat free mass is most optimal compared to BSA, body mass and height and is important in athletes displaying extreme anthropometry

Indexing all chambers to BSA with population-specific allometric b exponents, is optimal, however, until these values have been validated across cohorts it is recommended that standard linear scaling to BSA is undertaken in line with BSE guidelines for non-athletes whilst acknowledging the limitations of this approach

Indexed aortic root dimensions should be ratiometrically scaled to height. As aortic root dimension values typically fall within established normal limits, indexed aortic reference values may be helpful in the early detection of aortic pathologies in athletes who exceed these limits

Sex

Concentric LVH is extremely rare in female athletes and rare in male athletes

Female athletes present with smaller LV, RV and bi-atrial structural dimensions compared to male athletes

Males have larger aortic root dimensions compared to females with values of ≥ 40 mm for males and ≥ 38 mm for females being extremely rare. Values exceeding these limits may be indicative of pathology and further assessment would prove beneficial

Age

LV dimensions in adolescent athletes are larger when compared with non-athlete controls. LV cavity enlargement very rarely exceeds 60mm but in cases where it does, whilst also in the presence of an impairment of systolic or diastolic function, a diagnosis of DCM should be considered

Adolescent athletes present bi-atrial remodelling compared to non-athlete controls. However bi-atrial function is preserved with LA and RA EF similar between athletes and controls and thus signifies normal physiological remodelling

Aortic dilation is rare in adolescent athletes. The aortic diameter cut off values of 40mm for males and 38 mm for females may not be appropriate for the adolescent athlete and therefore scaling to height is warranted