St Vincent's Institute, Fitzroy, Victoria, Australia.
University of Melbourne, Parkville, Victoria, Australia.
Am J Physiol Heart Circ Physiol. 2024 May 1;326(5):H1269-H1278. doi: 10.1152/ajpheart.00422.2023. Epub 2024 Mar 8.
Increased left atrial (LA) size and reduced LA function have been associated with heart failure and atrial fibrillation (AF) in at-risk populations. However, atrial remodeling has also been associated with exercise training and the relationship between fitness, LA size, and function has not been defined across the fitness spectrum. In a cross-sectional study of 559 ostensibly healthy participants, comprising 304 males (mean age, 46 ± 20 yr) and 255 females (mean age, 47 ± 15 yr), we sought to define the relationship between cardiorespiratory fitness (CRF), LA size, and function. We also aimed to interrogate sex differences in atrial factors influencing CRF. Echocardiographic measures included biplane measures of LA volumes indexed to body surface area (LAVi) and atrial deformation using two-dimensional speckle tracking. CRF was measured as peak oxygen consumption (V̇o) during cardiopulmonary exercise testing (CPET). Using multivariable regression, age, sex, weight, and LAVi ( < 0.001 for all) predicted V̇o ( < 0.001, = 0.66 for combined model) After accounting for these variables, heart rate reserve added strength to the model ( < 0.001, = 0.74) but LA strain parameters did not predict V̇o. These findings add important nuance to the perception that LA size is a marker of cardiac pathology. LA size should be considered in the context of fitness, and it is likely that the adverse prognostic associations of increased LA size may be confined to those with LA enlargement and low fitness. Left atrial (LA) structure better predicts cardiorespiratory fitness (CRF) than LA function. LA function adds little statistical value to predictive models of peak oxygen uptake (V̇o) in healthy individuals, suggesting limited discriminatory for CRF once LA size is factored. In the wider population of ostensibly healthy individuals, the association between increased LA volume and higher CRF provides an important counter to the association between atrial enlargement and heart failure symptoms in those with cardiac pathology.
左心房（LA）增大和 LA 功能降低与高危人群中的心力衰竭和心房颤动（AF）有关。然而，心房重构也与运动训练有关，在整个健康范围内，健康状况、LA 大小和功能之间的关系尚未确定。在一项对 559 名表面健康参与者的横断面研究中，包括 304 名男性（平均年龄 46 ± 20 岁）和 255 名女性（平均年龄 47 ± 15 岁），我们试图确定心肺健康（CRF）、LA 大小和功能之间的关系。我们还旨在探讨影响 CRF 的心房因素的性别差异。超声心动图测量包括使用二维斑点追踪技术对 LA 容积指数（LAVi）和心房变形进行双平面测量。CRF 测量为心肺运动测试（CPET）期间的峰值摄氧量（V̇o）。使用多变量回归，年龄、性别、体重和 LAVi（所有 P < 0.001）预测 V̇o（所有 P < 0.001，合并模型 = 0.66）。在考虑到这些变量后，心率储备增强了模型的强度（P < 0.001， = 0.74），但 LA 应变参数不能预测 V̇o。这些发现为 LA 大小是心脏病理学标志物的观念增添了重要的细微差别。应根据健康状况考虑 LA 大小，并且 LA 增大和低健康状况患者的 LA 大小不良预后关联可能仅限于这些患者。LA 结构比 LA 功能更好地预测心肺健康（CRF）。LA 功能对健康个体峰值摄氧量（V̇o）预测模型的统计学价值贡献不大，这表明一旦考虑到 LA 大小，对 CRF 的区分度有限。在表面健康的个体的更广泛人群中，LA 容积增加与更高的 CRF 之间的关联为那些具有心脏病理学的患者的心房扩大与心力衰竭症状之间的关联提供了一个重要的反例。
