Key result
Overload type dictates distinct left atrial functional adaptations despite enlargement in up to ~87% of patients.
Why the study?
Arterial hypertension, mitral regurgitation, and endurance training are risk factors for atrial fibrillation, but the left atrial adaptive response to different loading conditions is not well characterized.
Does left atrial enlargement uniformly imply left atrial dysfunction across different types of overload (endurance training, hypertension, mitral regurgitation)?
Cross-Sectional (n=548)
Does left atrial enlargement uniformly imply left atrial dysfunction across different types of overload (endurance training, hypertension, mitral regurgitation)?
Left atrial enlargement represents a physiological adaptation with preserved function in athletes, whereas it represents pathological remodeling with dysfunction in patients with hypertension or mitral regurgitation.
Answers are grounded in this paper and cite their sources.
LA enlargement requires overload-specific functional assessment to distinguish adaptation from pathology; leaves open prospective AF risk stratification by remodeling phenotype.
INTRODUCTION: Arterial hypertension, mitral regurgitation (MR) and endurance training are risk factors for atrial fibrillation development. Our aim was to compare the LA adaptative response to different loading conditions by evaluating LA function through volumetric indices and deformation imaging. METHODS AND RESULTS: A population of 548 subjects was enrolled: 286 endurance athletes, 225 patients with arterial hypertension, and 37 with moderate to severe MR. Participants underwent 2D echocardiography with speckle-tracking as well as 3D echocardiography. Patients with LA enlargement, defined with a 2D cut-off value of ≥34 ml/m2, were compared amongst cohorts to assess for atrial function. LA enlargement was seen in 57% (n = 311) of the cohort: in 78% (n = 224) of athletes, 25% (n = 55) of hypertensive patients, and 87% (n = 32) of patients with MR. Compared to hypertensive and MR patients, athletes were younger, less burdened by comorbidities, with better diastolic function, and higher LA reservoir and conduit function, whereas no difference was seen in contractile function. Athletes in the lowest tercile of reservoir strain (T1, <30.30%) had the highest amount of exercise per week, more LV remodeling, and higher LA minimal volume. The majority of hypertensive patients with LA enlargement belonged to the lowest tercile for LA reservoir strain. MR was associated with the largest LA maximal volumes and lowest LA reservoir and conduit strain. CONCLUSION: The LA adapts differently to pressure and volume overload and is influenced by the amount of overload. LA enlargement may not be associated with the same degree of LA dysfunction in different at-risk populations.
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Lončarić et al. (2026) conducted a cross-sectional in Left atrial enlargement (n=548). Different loading conditions (endurance training, arterial hypertension, mitral regurgitation) vs. Compared among cohorts was evaluated on Left atrial enlargement (≥34 ml/m2) and atrial function. Left atrial enlargement was present in 78% of athletes, 87% of MR patients, and 25% of hypertensive patients, with distinct functional adaptations and dysfunction degrees based on the overload type.
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