Abstract
BACKGROUND: Prolonged high-intensity endurance exercise has been associated with myocardial structural remodeling. This study aimed to investigate left atrial-left ventricular-arterial (LA-LV-arterial) coupling in amateur marathon runners using three-dimensional speckle-tracking echocardiography (3D-STE). By comprehensively assessing cardiac structural adaptation and arterial stiffness, this study sought to elucidate the integrated heart-vascular interaction, which may serve as a predictor for cardiovascular risk. METHODS: A total of 93 amateur marathon runners were enrolled and categorized into two subgroups: 45 amateur ultramarathon runners (running distance of ≥50 km, UM group) and 48 amateur classic marathon runners (running distance of <50 km, M group). Additionally, 40 healthy volunteers were included as the control group (CON group). All subjects underwent conventional echocardiography combined with 3D-STE. The left atrial (LA) volume, functional parameters, and left ventricular strain parameters were compared among the three groups. Additionally, the correlations between left atrial stiffness index (LASI), pulse wave velocity to global longitudinal strain ratio (PWV/GLS), and the aforementioned parameters were analyzed, along with their influencing factors. RESULTS: Compared with the CON group, the LASI was significantly higher in the UM group (0.32±0.11) and the M group (0.33±0.14) (P<0.05). Similarly, the PWV/GLS ratio was significantly greater (less negative) in the UM group -(0.23±0.04) and the M group -(0.21±0.04) than in the control group (P<0.05). Both the UM and M groups exhibited significantly higher left atrial volumes (LAVs) measured by 3D-STE-including left atrial minimal volume (LAVmin), left atrial maximal volume (LAVmax), left atrial pre-systolic volume (LAVpreA), and left atrial maximal volume index (LAVImax)-compared to the control group (P<0.05). Furthermore, the UM group demonstrated significantly greater values than the M group (P<0.05). A significant negative correlation was observed between LASI and left atrial ejection fraction (LAEF) (P<0.05). Similarly, the PWV/GLS ratio showed significant negative correlations with LAVmin, LAVmax, LAVpreA, LAVImax and average weekly running mileage (P<0.05). Multivariate linear regression analysis revealed that weekly running distance was an independent predictor of left atrial-ventricular-arterial coupling (assessed by PWV/GLS and LASI) in amateur marathon runners (P<0.001). CONCLUSIONS: Following prolonged high-intensity endurance exercise, amateur marathon runners exhibit varying degrees of impairment in LA structure and function. Elevated LASI and PWV/GLS ratios serve as early indicators of abnormal left atrial-ventricular-arterial coupling in this population. 3D-STE demonstrates high sensitivity in detecting these subclinical alterations, providing valuable insights for evaluating the cardio-vascular interplay in amateur marathon runners.