Author(s): BAI, Y., SIXIANG, W., SHUYU, F., Institution: CHINA NATIONAL INSTITUTE OF SPORTS MEDICINE, Country: CHINA, Abstract-ID: 551

INTRODUCTION:
It investigates the cardiac structural and functional adaptations in elite national swimmers following altitude training. Utilizing comprehensive echo-cardiographic techniques, including M-mode, Doppler, and two-dimensional speckle tracking, the study assesses the impact of altitude training on the left and right ventricles, left atrium, and major blood vessels. The findings provide critical insights into the physiological remodeling and acute diastolic dysfunctions that occur post-training, emphasizing the need for meticulous medical monitoring to mitigate potential cardiovascular risks. These contributions align with the journal's focus on advancing our understanding of physiological adaptations to exercise and training in elite athletes.
METHODS:
This study included China elite national swimmers divided by their training schedules into plain and altitude training groups. Pre-and post-5-week training assessments included serum biomarkers and echocardiographic evaluations using M mode, Doppler, and two-dimensional speckle tracking echocardiography focusing on the left and right ventricles, left atrium, and major blood vessels.
RESULTS:
Post-altitude training, the ascending aortic diameter (AAO) and aortic sinus diameter (AOd) expanded (P=0.008, P=0.046). The MPA/AOd ratio significantly decreased (P=0.023), and LVEDD/AOd more closely approximated the "golden ratio," indicating harmonious physiological remodeling. (2) Altitude training led to acute diastolic dysfunction in the left ventricle, shown by decreased E peak (P=0.033), LASr, and LAScd (P=0.011, P=0.002). The decrease in the peak velocity of the late diastolic a' wave of the mitral annulus (Δa') was significant (P=0.010), more so in the altitude group than the plain group. Additionally, significant elevations in hypersensitive troponin I (TnI) (P=0.010) and creatine kinase (P=0.003) were observed in the altitude group. (3) After plain training, cardiac output (CO) and cardiac index (CI) decreased (P=0.022, P=0.030), with normal left ventricular ejection fraction (LVEF) and no systolic dysfunction. However, abnormalities were noted in two-dimensional speckle tracking echocardiography (2D-STE) in some athletes.
CONCLUSION:
Altitude training induces acute cardiovascular adaptations in elite swimmers, notably in aortic dimensions and left ventricular diastolic function, with earlier atrial changes raising atrial fibrillation risks. These findings necessitate careful medical monitoring, particularly using two-dimensional speckle tracking echocardiography to detect early systolic dysfunction and guide focused athlete care.