AIMS Mild to moderate functional mitral regurgitation (MR) is common in patients with heart failure and preserved ejection fraction (HFpEF) where it is usually considered as an innocent bystander. We hypothesized that MR in HFpEF reflects greater left atrial (LA) myopathy, leading to more adverse haemodynamics and poorer exercise reserve. METHODS AND RESULTS Patients with HFpEF (n = 280) with and without MR underwent echocardiography, invasive haemodynamic exercise testing, and expired gas analysis. As compared to non-MR-HFpEF (n = 163), patients with MR-HFpEF (n = 117; 78 mild and 39 moderate, central jet in 90%) were older, more likely female, with lower body mass and higher prevalence of atrial fibrillation (AF). HFpEF patients with MR displayed greater LA volume, reduced LA strain and compliance, and greater mitral annular dilatation, which was strongly correlated with LA dilatation (r = 0.63, P < 0.0001) but was only weakly related to left ventricular remodelling (r = 0.37). Patients with MR-HFpEF displayed worse biventricular function, more adverse pulmonary haemodynamics, impaired pulmonary vasodilatation, blunted right ventricular reserve, and reduced cardiac output with exercise as compared to non-MR-HFpEF. Importantly, these findings were maintained after excluding patients with HFpEF and AF, suggesting a role for LA myopathy in contributing to MR in HFpEF, independent of rhythm. CONCLUSIONS Functional MR in patients with HFpEF reflects LA myopathy, even in the absence of AF, and is associated with greater haemodynamic severity of disease and poorer functional capacity. Further study is required to better define causal mechanisms and potential treatments for MR and LA dysfunction in patients with HFpEF.

中文翻译：

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心力衰竭中的功能性二尖瓣反流和左心房肌病，射血分数保持不变。

AIMS轻度至中度的二尖瓣反流（MR）在心力衰竭和射血分数保留（HFpEF）的患者中很常见，通常被认为是无辜的旁观者。我们假设HFpEF中的MR反映出更大的左心房（LA）肌病，导致更多的不良血流动力学和较差的运动储备。方法和结果HFpEF（n = 280）合并和不合并MR的患者均接受了超声心动图，有创血流动力学运动测试和过期气体分析。与非MR-HFpEF（n = 163）相比，MR-HFpEF（n = 117； 78例轻度和39例中度中央喷射，占90％）患者年龄较大，女性更可能，体重较低且患病率较高心房颤动（AF）。患有MR的HFpEF患者显示出更大的LA体积，减少的LA应变和顺应性，以及更大的二尖瓣环扩张，与左心室扩张密切相关（r = 0.63，P <0.0001），而与左心室重塑关系不大（r = 0.37）。与非MR-HFpEF相比，MR-HFpEF的患者表现出较差的双心室功能，更不利的肺血流动力学，肺血管舒张受损，右心室储备减弱以及运动时心输出量降低。重要的是，这些发现在排除HFpEF和AF患者后得以维持，表明LA肌病在HFpEF中促成MR的作用，与节律无关。结论HFpEF患者的功能性MR即使在没有AF的情况下也反映出LA肌病，并且与疾病的血液动力学严重程度更高和功能能力较差有关。