Department of Pediatrics, Tokushima University, Tokushima, Japan
Department of Pediatrics, Tokushima University, Tokushima, Japan.
J Am Heart Assoc. 2018 Apr 19;7(9):e008670. doi: 10.1161/JAHA.118.008670.
The rate of left ventricular pressure decrease during isovolumic relaxation is traditionally assessed algebraically via 2 empirical indices: the monoexponential and logistic time constants (τ and τ). Since the pattern of right ventricular (RV) pressure decrease is quite different from that of the left ventricular, we hypothesized that novel kinematic model parameters are more appropriate and useful to evaluate RV diastolic dysfunction.
Eight patients with pulmonary arterial hypertension (age 12.5±4.8 years) and 20 normal subjects (control group; age 12.3±4.4 years) were enrolled. The kinematic model was parametrized by stiffness/restoring Ek and damping/relaxation μ. The model predicts isovolumic relaxation pressure as a function of time as the solution of dP/dt+(1/μ)dP/dt+EkP=0, based on the theory that the pressure decay is determined by the interplay of inertial, stiffness/restoring, and damping/relaxation forces. In the assessment of RV diastolic function, τ and τ did not show significant differences between the pulmonary arterial hypertension and control groups (46.8±15.5 ms versus 32.5±14.6 ms, and 19.6±5.9 ms versus 14.5±7.2 ms, respectively). The pulmonary arterial hypertension group had a significantly higher Ek than the control group (915.9±84.2 s versus 487.0±99.6 s, <0.0001) and a significantly lower μ than the control group (16.5±4.3 ms versus 41.1±10.4 ms, <0.0001). These results show that the RV has higher stiffness/elastic recoil and lower cross-bridge relaxation in pulmonary arterial hypertension.
The present findings indicate the feasibility and utility of kinematic model parameters for assessing RV diastolic function.
传统上，通过 2 个经验指数，即单指数和逻辑时间常数（τ和τ），对等容舒张期左心室压力下降率进行代数评估。由于右心室（RV）压力下降的模式与左心室非常不同，我们假设新型运动学模型参数更适合和有用，可用于评估 RV 舒张功能障碍。
共纳入 8 例肺动脉高压（年龄 12.5±4.8 岁）患者和 20 名正常对照者（对照组；年龄 12.3±4.4 岁）。运动学模型由僵硬/恢复 Ek 和阻尼/松弛 μ 进行参数化。该模型基于压力衰减由惯性、僵硬/恢复和阻尼/松弛力相互作用决定的理论，将等容舒张压力作为时间的函数进行预测，即 dP/dt+(1/μ)dP/dt+EkP=0。在 RV 舒张功能评估中，τ和τ在肺动脉高压组和对照组之间无显著差异（分别为 46.8±15.5 ms 与 32.5±14.6 ms 和 19.6±5.9 ms 与 14.5±7.2 ms）。肺动脉高压组的 Ek 明显高于对照组（915.9±84.2 s 与 487.0±99.6 s，<0.0001），μ 明显低于对照组（16.5±4.3 ms 与 41.1±10.4 ms，<0.0001）。这些结果表明，RV 在肺动脉高压中具有更高的僵硬/弹性回弹和更低的交联松弛。
本研究结果表明，运动学模型参数评估 RV 舒张功能具有可行性和实用性。
