Extreme phenotypes of the female athlete's heart: A sports-specific cardiac magnetic resonance imaging study

Aims Differentiating physiological exercise-induced cardiac remodelling (EICR) from pathology is challenging, especially in female athletes, where studies using state-of-The-Art imaging techniques are lacking. We aimed to investigate extreme phenotypes of EICR in female elite athletes using magnetic resonance imaging (MRI). Methods and results Cross-sectional, multicentre study in female elite athletes using contrast-enhanced cardiac MRI. Left and right ventricle (LV, RV) indices and LV mass (LVM)-To-LV end-diastolic volume (EDV) ratios were investigated, indexed by body surface area (BSA). Cardiac remodelling was determined comparing cardiac MRI metrics to female reference values, stratified by ESC sports classification (endurance, mixed, power/skill). In 173 female elite athletes (median age 25 years, median 18h training/week, 97% Caucasian), mean LV EDV/BSA and LVM/BSA were 108 ± 13mL/m² and 50 ± 10g/m2, with lower LVM/LV EDV ratios (0.5 ± 0.1) than the general population (0.7 ± 0.1g/mL; P < 0.001). Most athletes (71%) had isolated LV EDV increases; LVM increases (18%) commonly coincided with LV EDV increases. Compared with the general population (45 ± 7g/m2), only mixed (48 ± 9g/m2; P = 0.021) and endurance athletes (53 ± 11g/m2; P < 0.001) exhibited greater mean LVM with endurance athletes surpassing mixed athletes (P = 0.004). Mixed and endurance showed comparably greater median biventricular EDV compared with power/skill athletes [LV: 109 (103-119) and 111 (101-118) vs. 99 (92-105); RV: 110 (103-118) and 112 (105-124) vs. 101 (95-104) mL/m2; P < 0.001]. Maximum wall thickness > 11mm was rare (2%). Global T1 time was 968 ± 22ms; extracellular volume was 25 ± 4%. Conclusion Female elite athletes, particularly endurance-Trained athletes, display EICR marked by increased ventricular volumes, without prominent increases in LVM or wall thickness.