Department of Radiology and Nuclear Medicine, Amsterdam Cardiovascular Sciences, VU University Medical Center, Amsterdam, The Netherlands.
Department of Cardiovascular Sciences, University of Leuven, Leuven, Belgium.
Adv Exp Med Biol. 2018;1065:123-138. doi: 10.1007/978-3-319-77932-4_8.
Recent advances in cardiac imaging techniques have substantially contributed to a growing interest in the analysis of global cardiac chamber dimensions and regional myocardial deformation. During the cardiac cycle, ventricular luminal volume varies due to the contraction process, which also confers a shape change including substantial alteration of long axis length, as well as rotation of the base compared to the apex. Local deformation can be assessed by strain (rate) analysis. Reviewing the present literature, it must be concluded that there is no single metric available to comprehensively characterize ventricular function. Every candidate advanced thus far has been found to incompletely reflect ventricular performance. This observation is not surprising in view of the complexity of the cardiac pump system. Additionally, sex-specific modifiers may play a role. More than three decades ago, it was shown that on average the ventricular volume is smaller in healthy women compared to matched males. Therefore, the present contribution concerns the interpretation of data derived from the healthy heart in both men and women. Starting from the classical Starling concept, we apply a simple mathematical transformation which permits an insightful representation of ventricular mechanics. Relating end-systolic volume (ESV) to end-diastolic volume creates the ventricular volume regulation graph which features the pertinent working point of an individual heart. This fundamental approach illustrates why certain proposed performance indexes cannot individually reveal the essence of ventricular systolic function. We demonstrate that particular metrics are highly interconnected and just tell us the same story in a different disguise. It is imperative to understand which associations exist and if they expectedly are (nearly) linear or frankly nonlinear. Notably, ejection fraction (EF) is primarily determined by ESV, while in turn EF is not much different from ventriculo-arterial coupling (VAC). Insight into cardiac function is promoted by identification of the paramount/essential components involved. The smaller ESV (p < 0.0001) implies that EF is higher in women and may also have consequences for VAC.
近年来，心脏成像技术的进步极大地促进了人们对心脏腔室尺寸和局部心肌变形的分析兴趣。在心脏周期中，由于心室的收缩过程，心室管腔容积发生变化，这也导致了形状的改变，包括长轴长度的显著变化以及基底相对于心尖的旋转。局部变形可以通过应变（率）分析来评估。回顾目前的文献，必须得出结论，没有单一的指标可以全面描述心室功能。迄今为止提出的每一个候选指标都被发现不能完全反映心室的性能。鉴于心脏泵系统的复杂性，这种观察结果并不奇怪。此外，性别特异性修饰因子可能也会起作用。三十多年前，人们发现健康女性的心室容积平均比匹配的男性小。因此，本研究涉及男性和女性健康心脏衍生数据的解释。从经典的 Starling 概念出发，我们应用了一个简单的数学变换，可以对心室力学进行直观的表示。将收缩末期容积（ESV）与舒张末期容积（EDV）相关联，创建了心室容积调节图，该图展示了个体心脏的相关工作点。这种基本方法说明了为什么某些提出的性能指标不能单独揭示心室收缩功能的本质。我们证明了特定的指标是高度相互关联的，只是以不同的伪装讲述了同一个故事。了解存在哪些关联，以及它们是否预期是（几乎）线性或坦率的非线性，这一点至关重要。值得注意的是，射血分数（EF）主要由 ESV 决定，而 EF 与心室-动脉偶联（VAC）又几乎相同。通过确定涉及的主要/基本组成部分，可以促进对心脏功能的深入了解。较小的 ESV（p<0.0001）意味着女性的 EF 更高，这也可能对 VAC 产生影响。
