Funding Acknowledgements Type of funding sources: None. Purpose Aortic dilatation is associated with acute aortic pathology. Cardiac magnetic resonance (CMR) data in asymptomatic elite athletes is lacking. Therefore, we investigated the prevalence of aortic dilatation in a cohort of elite-level athletes using CMR. Methods We performed a cross-sectional study of aortic dimensions among elite-level (national-, international-, Olympic-, Paralympic-level or comparable) athletes. All athletes were asymptomatic and examined during pre-participation screening. Each underwent CMR with 3D whole heart in diastole (1.5 mm voxel) for aortic measurements, next to cine imaging, late gadolinium enhancement (LGE), and T1-mapping. We defined dilatation as 38 and 40 mm at the aortic root (sinus of Valsalva cusp-cusp), 27 and 31 mm at the sinotubular junction, and 23 and 26 mm at the level of the diaphragm, in male- and female athletes, respectively. Athletes were grouped for having 0- (normal), 1-, 2- or 3 measurements above cut-off values. Results We screened 156 athletes, 41% female, with a mean age (±SD) of 28±7 and body surface area (BSA) of 2.0±0.2 m2. Mean aortic dimensions were 33±4 mm for the sinus of Valsalva, 28±3 mm for the sinotubular junction, 20±3 mm for the aorta at diaphragm. We observed indexed end-diastolic volumes (EDVi) of 122±20 and 123±20 ml/m2, indexed end-systolic volumes (ESVi) of 53±13 and 54±16 ml/m2, stroke volumes (SV) of 129±36 and 126±39 ml, and ejection fractions (EF) of 56±5 and 55±6 %, in the left- (LV) and right ventricle (RV), respectively Fifty-three (34%) athletes, of which 45% female, had 1 or 2 aortic measurements above conventional cut-off values (Table 1). Eleven (7%), 18% female, had 2 aortic measurements above cut-off values. No athlete had all 3 measurements above cut-offs values. Athletes with 2 dilated measurements compared to athletes with 1 or 0 dilated measurements, had greater LV EDVi (145±19 vs. 119±18 vs. 120±19 ml/m2, p<0.001), greater RV EDVi (142±18 vs. 119±17 vs. and 122±20 ml/m2, p=0.002), greater LV ESVi (66±10 vs. 51±13 vs. 52±13 ml/m2, p=0.002), greater RV ESVi (66±10 vs. 53±13 vs. 53±17 ml/m2, p=0.039), greater LV SV (156±26 vs. 132±35 vs. 125±36 ml, p=0.020), and greater RV SV (152±25 vs. 130±34 vs. 121±41 ml, p=0.031), 2- vs, 1- vs. 0 dilated segments, respectively (Table 1, Figure 1). Athletes with dilated measurements had no LGE (excluding the hinge point), no difference in T1-mapping times, or LV- and RV EF, compared to athletes without dilated measurements. Conclusion One in three elite-athletes has dilatation in one or more aortic segments, including the sinus of Valsalva, sinotubular junction, or the aorta at diaphragm. Athletes with 2 dilated measurements (7%) had greater LV- and RV EDVi, ESVi, and SV, suggesting an association with ventricular volumes. Our findings in asymptomatic elite athletes, with normal EF and no LGE and comparable T1-mapping times, could be a sign of an outspoken physiological sports adaptation, instead of pathology.

Background/Introduction In the general population, cardiac magnetic resonance imaging (CMR) T1 mapping is an established tool used for cardiac tissue characterisation. Such characterisation is of particular interest in athletes, as differentiation of the “grey zone” between physiological adaptation to sports and myocardial pathology can be highly challenging. To correctly interpret individual T1 times, T1 times are conventionally compared with normal values derived from healthy controls. However, whether these normative T1 values can be applied to elite athletes, who commonly demonstrate the most extreme cardiac adaptation, is unknown. Purpose To determine whether there are gender-specific differences in normative T1 times between elite athletes and healthy controls. Methods This study is a cross-sectional assessment of healthy athletes included the ELITE-cohort. ELITE includes athletes at national, international, and Olympic level in the Netherlands, aged sixteen years or older and without a history of cardiovascular disease. All athletes undergo standard periodic preparticipation screening with cardiovascular magnetic resonance imaging (Phillips 1.5 Tesla), including native T1 mapping. For the current study, we compared athletes to healthy controls per gender group. T1 inversion times were calculated in Circle Cardiovascular software (v5.12); means for global and segmented myocardium, according to the AHA 16-segment model, were determined using R (v4.1.4). Results A total of 81 elite athletes (35 women, 43.2%) with a median (IQR) age of 26 (22.0–29.55) years and 55 healthy controls (27 women, 49.1%), with a mean age of 38.4±15 years were included (Table 1). Overall, mean global T1 times were markedly shorter in athletes compared with controls (959±21.1ms vs. 984±26.6ms, P<0.001). This difference was also present in both women (athletes 968±18.5ms vs controls 999±26.5ms, P<0.001) and men (athletes 952±20.3ms vs controls 970±18.0ms, P<0.001). We observed gender differences in T1 times within both the athlete (men 952±20.3ms vs women 968±18.5ms, P<0.001) and the control group (men 984±26.6ms vs women 999±26.5ms, P<0.001). Gender specific differences in T1 times were consistent between athletes and controls in the basal-, mid- and apical slices, as well as across all 16 segments (Figure panels A and B). Conclusion(s) Athletes demonstrate markedly shorter T1 times as compared with healthy controls, both in women and men. Sex-specific, athlete-normative T1 times should be taken into account when interpreting T1 times in athletes undergoing cardiac evaluation. Funding Acknowledgement Type of funding sources: Public Institution(s). Main funding source(s): Amsterdam Movement Sciences and the Dutch Olympic Committee*Dutch Sports Federation

Background/Introduction SARS-CoV-2 (subclinical) myocarditis has been demonstrated in up to 5% in athletes, and is currently a topic being intensively investigated. However, more subtle changes in function and volumetric parameters have been less well documented, especially in elite athletes, who perform at the highest levels of sports, with potentially the most outspoken adaptation. Purpose To determine differences in cardiac function and volumetric parameters using cardiac magnetic resonance imaging (CMR) in elite athletes recovered from a SARS-CoV-2 infection as compared to non-infected elite athletes (controls). Methods We included elite athletes from the ELITE (Evaluation of Lifetime Intensive Top-level sports and Exercise) cohort, who voluntary undergo cardiovascular pre-participation screenings, which includes cardiac magnetic resonance imaging (CMR). SARS-CoV-2 infection was diagnosed with a positive-PCR or antibody test (if unvaccinated). The primary outcome was the incidence of structural cardiac changes on CMR, defined as LV/RV BSA indexed-EDV (EDVi), LV/RV BSA indexed-ESV (ESVi), LV/RV EF, presence of pathological late gadolinium enhancement (LGE) (excluding hinge point fibrosis), and T1 times. Results We included 234 elite athletes, mean age 27 (±7), 39% female, with main athletic disciplines (≥10 hours/week) of cycling (24%), field hockey (13%), and water polo (12%). In total 69 elite athletes had documented SARS-CoV-2 infection, and 165 were documented as not exposed to SARS-CoV-2. The majority reported mild symptoms 61/69 (88%), 1/69 (1%) severe symptoms, and 7/69 (11%) no symptoms. Mean time between infection and CMR was 2.8 (±2) months. CMR showed no significant difference between elite athletes with SARS-CoV-2 and without (Table) in mean LVEDVi (117±19 vs 120±19 ml/m2, p=0.29), LVESVi (50.6±11 vs 53.2±11 ml/m2, p=0.12), LVEF (56.9% ±5 vs 55.8% ±5, p=0.14), RVEDVi (120±20 vs 122±19 ml/m2, p=0.56), RVESVi (54.5±11 vs 56.2±11 ml/m2, p=0.29), and RVEF (54.6% ±4 vs 53.9% ±5, p=0.23). In 4/69 (4.7%) vs 1/165 (1.3%) pathological non-ischemic pattern of myocardial LGE was present (≤20% of total LV mass), of which one athlete (1.2%) showed increased T1 time, all with no deterioration in right and left ventricle function and volumetric parameters (Figure) after SARS-CoV-2 infection. All athletes made a full recovery and returned to elite competitive sports. Conclusion(s) This cross-sectional study of elite athletes demonstrates that infection with SARS-CoV-2 is not associated with deterioration in cardiac function and volumetric parameters on CMR compared with non-infected athletes, also in the small subset of athletes with pathological LGE patterns after SARS-CoV-2 infection. Prospective studies with long-term follow-up are needed to establish whether intensive sports is associated with long-term cardiac deleterious effects in elite athletes exposed to SARS-CoV-2. Funding Acknowledgement Type of funding sources: Foundation. Main funding source(s): Dutch Heart FoundationDutch National Olympic Committee & National Sports Federation (NOC*NSF)