This study tested the hypothesis that early left ventricular (LV) relaxation is impaired in older obese heart failure with preserved ejection fraction (HFpEF) patients, and related to decreased peak exercise oxygen uptake (peak VO₂). LV strain and strain rate were measured by feature tracking of magentic resonance cine images in 79 older obese HFpEF patients (mean age: 66 years; mean BMI: 38 kg/m²) and 54 healthy control participants. LV diastolic strain rates were indexed to cardiac preload as estimated by echocardiography derived diastolic filling pressures (E/e'), and correlated to peak VO₂. LV circumferential early diastolic strain rate was impaired in HFpEF compared to controls (0.93±0.05 s^-1 vs 1.20±0.07 s^-1, p=0.014); however, we observed no group differences in early LV radial or longitudinal diastolic strain rates. Isolating myocardial relaxation by indexing all three early LV diastolic strain rates (i.e. circumferential, radial, and longitudinal) to E/e' amplified the group difference in early LV diastolic circumferential strain rate (0.08±0.03 vs 0.13±0.05, p<0.0001), and unmasked differences in early radial and longitudinal diastolic strain rate. Moreover, when indexing to E/e', early LV diastolic strain rates from all three principal strains, were modestly related with peak VO₂ (R=0.36, -0.27, 0.35, respectively, all p<0.01); this response, however, was almost entirely driven by E/e' itself, (R=-0.52, P<0.001). Taken together, we found that while LV relaxation is impaired in older obese HFpEF patients, and modestly correlates with their severely reduced peak exercise VO₂, LV filling pressures appear to play a much more important role in determining exercise intolerance.

中文翻译：

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射血分数保留的肥胖性心力衰竭的左心室舒张功能障碍和运动不耐受

本研究检验了以下假设：射血分数保留的老年肥胖心力衰竭 (HFpEF) 患者的早期左心室 (LV) 舒张功能受损，并且与峰值运动摄氧量（峰值 VO 2 ）降低_有关。^{通过对 79 名老年肥胖 HFpEF 患者（平均年龄：66 岁；平均 BMI：38 kg/m 2}）和 54 名健康对照参与者的磁共振电影图像进行特征跟踪，测量左心室应变和应变率。左心室舒张应变率与心脏前负荷相关，心脏前负荷由超声心动图得出的舒张充盈压 (E/e') 估计，并与峰值 VO ₂相关。与对照组相比，HFpEF 中左心室周向舒张早期应变率受损（0.93±0.05 s ^-1对比 1.20±0.07 s ^-1，p=0.014）；然而，我们观察到早期 LV 径向或纵向舒张应变率没有组间差异。通过将所有三种早期 LV 舒张应变率（即周向、径向和纵向）指数化为 E/e' 来隔离心肌松弛，放大了早期 LV 舒张周向应变率的组间差异（0.08±0.03 与 0.13±0.05，p<0.0001） ，以及早期径向和纵向舒张应变率的明显差异。_{此外，当以 E/e' 为索引时，来自所有三个主要应变的早期 LV 舒张应变率与峰值 VO 2}适度相关（分别为 R=0.36、-0.27、0.35，所有 p<0.01）；然而，这种响应几乎完全由 E/e' 本身驱动（R=-0.52，P<0.001）。综上所述，我们发现，虽然老年肥胖 HFpEF 患者的 LV 舒张功能受损，并且与其严重降低的峰值运动 VO ₂略有相关，但 LV 充盈压似乎在确定运动不耐受方面发挥着更重要的作用。