BACKGROUND Right ventricular (RV) hemodynamic performance determines the prognosis of patients with RV pressure overload. Using ultrafast ultrasound, natural wave velocity (NWV) induced by cardiac valve closure was proposed as a new surrogate to quantify myocardial stiffness. OBJECTIVES This study aimed to assess RV NWV in rodent models and children with RV pressure overload vs control subjects and to correlate NWV with RV hemodynamic parameters. METHODS Six-week-old rats were randomized to pulmonary artery banding (n = 6), Sugen hypoxia-induced pulmonary arterial hypertension (n = 7), or sham (n = 6) groups. They underwent natural wave imaging, echocardiography, and hemodynamic assessment at baseline and 6 weeks postoperatively. The authors analyzed NWV after tricuspid and after pulmonary valve closure (TVC and PVC, respectively). Conductance catheters were used to generate pressure-volume loops. In parallel, the authors prospectively recruited 14 children (7 RV pressure overload; 7 age-matched control subjects) and compared RV NWV with echocardiographic and invasive hemodynamic parameters. RESULTS NWV significantly increased in RV pressure overload rat models (4.99 ± 0.27 m/s after TVC and 5.03 ± 0.32 m/s after PVC in pulmonary artery banding at 6 weeks; 4.89 ± 0.26 m/s after TVC and 4.84 ± 0.30 m/s after PVC in Sugen hypoxia at 6 weeks) compared with control subjects (2.83 ± 0.15 m/s after TVC and 2.72 ± 0.34 m/s after PVC). NWV after TVC correlated with both systolic and diastolic parameters including RV dP/dtmax (r = 0.75; P < 0.005) and RV Ees (r = 0.81; P < 0.005). NWV after PVC correlated with both diastolic and systolic parameters and notably with RV end-diastolic pressure (r = 0.65; P < 0.01). In children, NWV after both right valves closure in RV pressure overload were higher than in healthy volunteers (P < 0.01). NWV after PVC correlated with RV E/E' (r = 0.81; P = 0.008) and with RV chamber stiffness (r = 0.97; P = 0.03). CONCLUSIONS Both RV early-systolic and early-diastolic myocardial stiffness show significant increase in response to pressure overload. Based on physiology and our observations, early-systolic myocardial stiffness may reflect contractility, whereas early-diastolic myocardial stiffness might be indicative of diastolic function.

中文翻译：

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通过自然波成像评估右心室压力过载对心肌僵硬度的影响。


背景技术右心室（RV）血流动力学性能决定右心室压力超负荷患者的预后。使用超快超声，由心脏瓣膜关闭引起的自然波速度（NWV）被提议作为量化心肌僵硬度的新替代指标。目的 本研究旨在评估啮齿动物模型和右心室压力超负荷儿童与对照受试者的右心室净波值 (NWV)，并将 NWV 与右心室血流动力学参数相关联。方法 六周龄大鼠被随机分为肺动脉束带组 (n = 6)、Sugen 缺氧诱导的肺动脉高压组 (n = 7) 或假手术组 (n = 6)。他们在基线和术后 6 周接受了自然波成像、超声心动图和血流动力学评估。作者分析了三尖瓣和肺动脉瓣关闭后的 NWV（分别为 TVC 和 PVC）。电导导管用于产生压力-体积环。与此同时，作者前瞻性地招募了 14 名儿童（7 名右心室压力超负荷；7 名年龄匹配的对照受试者），并将 RV NWV 与超声心动图和有创血流动力学参数进行比较。结果 RV 压力超载大鼠模型中 NWV 显着增加（6 周时肺动脉束带中 TVC 后为 4.99 ± 0.27 m/s，PVC 后为 5.03 ± 0.32 m/s；TVC 后为 4.89 ± 0.26 m/s，TVC 后为 4.84 ± 0.30 m/s与对照受试者（TVC 后 2.83 ± 0.15 m/s 和 PVC 后 2.72 ± 0.34 m/s）相比，PVC 后 6 周缺氧时的时间为 2.72 ± 0.34 m/s。 TVC 后的 NWV 与收缩压和舒张压参数相关，包括 RV dP/dtmax (r = 0.75；P < 0.005) 和 RV Ees (r = 0.81；P < 0.005)。 PVC 后的 NWV 与舒张压和收缩压参数相关，特别是与 RV 舒张末压相关（r = 0.65；P < 0.01）。 在儿童中，右心室压力超负荷时右瓣膜关闭后的 NWV 高于健康志愿者（P < 0.01）。 PVC 后的 NWV 与 RV E/E'（r = 0.81；P = 0.008）和 RV 室刚度（r = 0.97；P = 0.03）相关。结论 RV 收缩早期和舒张早期心肌僵硬度均显示出对压力超负荷的反应显着增加。根据生理学和我们的观察，收缩早期心肌僵硬度可能反映收缩性，而舒张早期心肌僵硬度可能表明舒张功能。