High intensity training is associated with specific cardiac remodeling in young female athletes

AIMS: High-intensity physical training induces cardiac remodelling, but data on the female athlete's heart are limited. We aimed to determine the normal echocardiographic (ECHO) and electrocardiographic (ECG) indices in young female athletes, compare them with female non-athletes and male athletes, and evaluate differences between female athletes of different races/ethnicities and types of sports. METHODS AND RESULTS: We searched four databases for studies including female athletes aged 18-35. A meta-analysis compared cardiovascular indices between female athletes and the groups above. We included 41 quantitative studies enrolling 11 956 female athletes, 14 014 male athletes, and 549 female non-athletes. Mean age (95% confidence intervals) in years was 22.4 (21.5-23.3) for female athletes, 23.7 (22.3-25.0) for female non-athletes, and 22.3 (21.3-23.3) for male athletes. Female athletes had higher left ventricular end-diastolic volume index [72.5 (66.3-78.8) vs. 55.4 (46.4-64.7) mL/m², P = 0.001], left ventricular mass index (LVMi) [80.8 (75.9-85.7) vs. 62.1(56.6-67.6) g/m², P < 0.0001], and left atrial volume index [29.2 (25.4-32.9) vs. 22.4 (18.7-26.1) mL/m², P = 0.01] than female non-athletes. The LVMi was 21% higher in male athletes than female athletes [98.3 (89.7-106.9) vs. 81.4 (76.6-86.2) g/m2, P < 0.0001]. Black female athletes had more frequent T-wave inversions on ECG than other races/ethnicities [15.2 (7.3-28.8) % of Black vs. 5.4 (2.9-9.9) % of White vs. 2.6 (0.7-9.9) % of Pacific Islanders vs. 0.7 (0.04-9.7) % of Metis, P = 0.04]. CONCLUSION: We confirmed sex-specific left ventricular remodelling, with more eccentric remodelling in female athletes. Black female athletes showed more T-wave inversions than female athletes of other races/ethnicities. Our aggregate means of ECHO and ECG indices may serve as normative values for young female athletes.