Determinants of left ventricular ejection fraction and a novel method to improve its assessment of myocardial contractility
Determinants of left ventricular ejection fraction and a novel method to improve its assessment of myocardial contractility
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DOI：
10.1186/s13613-019-0526-7
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发表时间：
2019-04-16
影响因子：
8.1
通讯作者：
Pinsky, Michael R.
中科院分区：
文献类型：
--
作者：
Monge Garcia, Manuel Ignacio;Jian, Zhongping;Pinsky, Michael R.
背景本研究的目的是量化不同心血管因素对左心室射血分数（LVEF）的影响，并测试考虑这些因素的新型 LVEF 计算方法。结果对 10 头猪进行了研究。实验方案包括依次改变后负荷、前负荷和收缩性。每次干预前后均获得左心室压力-容积（PV）环和外周动脉压。 LVEF 计算为每搏输出量 (SV)/舒张末期容积 (EDV)。我们研究了整体心脏功能变量：左心室收缩末期弹性（Ees）、有效动脉弹性（Ea）、舒张末期容量和心率。通过从舒张末期 PV 关系获得的心室舒张时间 () 和心室刚度常数 () 来评估舒张功能。心室-动脉耦合 (VAC) 是心血管功能指数，计算公式为 Ea/Ees。左心室机械效率 (LVeff) 计算为行程功与左心室压力容积面积之比。使用线性混合模型来确定所有实验条件下心脏因素（Ees、Ea、EDV 和心率）、VAC 和 LVeff 对 LVEF 的影响。 LVEF主要与Ees和Ea有关。 LVEF 与 VAC 和 LVeff 之间存在很强的相关性（分别为 r(2)=0.69 和 r(2)=0.94）。 LVEF与Ees之间的关系良好(r(2)=0.43)。将 LVEF 调整为后负荷 (LVEFEA=EFxEa) 可以更好地估计 Ees (r(2)=0.75)，并改善对 LV 收缩力变化的跟踪，即使当外周 Ea 用作替代时也是如此 (Ea=径向 MAP/SV；r(2)=0.73)。 结论 LVEF 主要受收缩力和后负荷变化影响，并且与 VAC 和 LVeff 密切相关。考虑后负荷影响的 LVEF 调整可以更好地评估 LV 收缩力。
BackgroundThe aim of this study was to quantify the impact of different cardiovascular factors on left ventricular ejection fraction (LVEF) and test a novel LVEF calculation considering these factors.Results10 pigs were studied. The experimental protocol consisted of sequentially changing afterload, preload and contractility. LV pressure-volume (PV) loops and peripheral arterial pressure were obtained before and after each intervention. LVEF was calculated as stroke volume (SV)/end-diastolic volume (EDV). We studied global cardiac function variables: LV end-systolic elastance (Ees), effective arterial elastance (Ea), end-diastolic volume and heart rate. Diastolic function was evaluated by means of the ventricular relaxation time () and ventricular stiffness constant () obtained from the end-diastolic PV relationship. Ventriculo-arterial coupling (VAC), an index of cardiovascular performance, was calculated as Ea/Ees. LV mechanical efficiency (LVeff) was calculated as the ratio of stroke work to LV pressure-volume area. A linear mixed model was used to determine the impact of cardiac factors (Ees, Ea, EDV and heart rate), VAC and LVeff on LVEF during all experimental conditions. LVEF was mainly related to Ees and Ea. There was a strong relationship between LVEF and both VAC and LVeff (r(2)=0.69 and r(2)=0.94, respectively). The relationship between LVEF and Ees was good (r(2)=0.43). Adjusting LVEF to afterload (LVEFEA=EFxEa) performed better for estimating Ees (r(2)=0.75) and improved the tracking of LV contractility changes, even when a peripheral Ea was used as surrogate (Ea=radial MAP/SV; r(2)=0.73).ConclusionsLVEF was mainly affected by contractility and afterload changes and was strongly related to VAC and LVeff. An adjustment to LVEF that considers the impact of afterload provided a better assessment of LV contractility.