Department of Kinesiology, University of Texas at Arlington, Arlington, Texas.
Section on Cardiovascular Medicine, Department of Internal Medicine, Wake Forest School of Medicine, Winston Salem, North Carolina.
Am J Physiol Heart Circ Physiol. 2021 Apr 1;320(4):H1535-H1542. doi: 10.1152/ajpheart.00610.2020. Epub 2021 Feb 12.
This study tested the hypothesis that early left ventricular (LV) relaxation is impaired in older obese patients with heart failure with preserved ejection fraction (HFpEF), and related to decreased peak exercise oxygen uptake (peak V̇o). LV strain and strain rate were measured by feature tracking of magnetic resonance cine images in 79 older obese patients with HFpEF (mean age: 66 yr; mean body mass index: 38 kg/m) and 54 healthy control participants. LV diastolic strain rates were indexed to cardiac preload as estimated by echocardiography derived diastolic filling pressures (), and correlated to peak V̇o. LV circumferential early diastolic strain rate was impaired in HFpEF compared with controls (0.93 ± 0.05/s vs. 1.20 ± 0.07/s, = 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 amplified the group difference in early LV diastolic circumferential strain rate (0.08 ± 0.03 vs. 0.13 ± 0.05, < 0.0001), and unmasked differences in early radial and longitudinal diastolic strain rate. Moreover, when indexing to , early LV diastolic strain rates from all three principal strains, were modestly related with peak V̇o ( = 0.36, -0.27, and 0.35, respectively, all < 0.01); this response, however, was almost entirely driven by itself, ( = -0.52, < 0.001). Taken together, we found that although LV relaxation is impaired in older obese patients with HFpEF, and modestly correlates with their severely reduced peak exercise V̇o, LV filling pressures appear to play a much more important role in determining exercise intolerance. Using a multimodal imaging approach to uncouple tissue deformation from atrial pressure, we found that left ventricular (LV) relaxation is impaired in older obese patients with HFpEF, but only modestly correlates with their severely reduced peak V̇o. In contrast, the data show a much stronger relationship between elevated LV filling pressures and exercise intolerance, refocusing future therapeutic priorities.
这项研究检验了一个假设，即在射血分数保留的心力衰竭（HFpEF）的老年肥胖患者中，早期左心室（LV）松弛受损，与运动峰值摄氧量（peak V̇o）降低有关。通过磁共振电影图像的特征跟踪，在 79 名老年肥胖 HFpEF 患者（平均年龄：66 岁；平均体重指数：38kg/m）和 54 名健康对照参与者中测量了 LV 应变和应变率。LV 舒张应变率通过超声心动图衍生的舒张充盈压（）估计的心脏前负荷进行指数化，并与 peak V̇o 相关。与对照组相比，HFpEF 患者的 LV 舒张早期圆周应变率受损（0.93±0.05/s 比 1.20±0.07/s，=0.014）；然而，我们观察到三组 LV 径向和纵向舒张早期应变率之间没有组间差异。通过将所有三种 LV 舒张早期应变率（即圆周、径向和纵向）指数化到心肌松弛，放大了 LV 舒张早期圆周应变率的组间差异（0.08±0.03 比 0.13±0.05，<0.0001），并揭示了早期径向和纵向舒张应变率的差异。此外，当指数化到时，来自所有三个主应变的 LV 舒张早期应变率与 peak V̇o 呈中度相关（分别为=0.36、-0.27 和 0.35，均<0.01）；然而，这种反应几乎完全由本身驱动，= -0.52，<0.001）。综上所述，我们发现，尽管老年肥胖 HFpEF 患者的 LV 松弛受损，并且与他们严重降低的运动峰值 V̇o 适度相关，但 LV 充盈压在确定运动不耐受方面似乎起着更为重要的作用。通过使用多模态成像方法将组织变形与心房压力解耦，我们发现，老年肥胖 HFpEF 患者的 LV 松弛受损，但与他们严重降低的峰值 V̇o 仅适度相关。相比之下，数据显示 LV 充盈压与运动不耐受之间存在更强的关系，这重新聚焦了未来的治疗重点。
