The ventricular pressure-volume diagram revisited.

Sagawa, Kiichi

doi:10.1161/01.res.43.5.677

Cited by 453 publications

(151 citation statements)

References 57 publications

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“…Ventricular power output (VPO) was calculated by the formula: VPO = SW * heart rate (5) Normalized minor axis circumferential stroke work was calculated as: SW = fc de (6) 996 and myocardial power output (MPO) was calculated as: MPO = heart rate*fcde (7) where 6 was circumferential midwall equatorial wall stress, and E was circumferential midwall equatorial strain (see Appendix). Left Ventricular End DiastolicVolume(r FIGURE 3.…”

Section: Methodsmentioning

confidence: 99%

Linearity of the Frank-Starling relationship in the intact heart: the concept of preload recruitable stroke work.

Glower¹,

Spratt²,

Snow³

et al. 1985

Circulation

813

420

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The Frank-Starling relationship generally has been examined with filling pressure as the index of preload, resulting in a curvilinear function that plateaus at higher filling pressures. To investigate this relationship further in the intact heart, 32 dogs were chronically instrumented with left ventricular and pleural micromanometers and with regional (10 dogs) or global (22 dogs) ultrasonic dimension transducers. Seven days after implantation, left ventricular pressure and regional or global dimensions were recorded in the conscious state. After autonomic blockade, preload was varied by vena caval occlusion. Myocardial function was assessed by calculating regional or global stroke work, and preload was measured as end-diastolic segment length or chamber volume. The relationship between stroke work and either end-diastolic segment length or chamber volume (termed the preload recruitable stroke work relationship) was highly linear in every study (mean r = .97) and could be quantified by a slope (Mw) and x-intercept (L,). Previous nonlinear relationships between stroke work and filling pressure seemed to reflect the exponential diastolic pressure-volume curve. Over the physiologic range of systolic arterial pressures produced by infusion of nitroprusside or phenylephrine, no significant change was observed in Mw or Lw in the normal dog. Calcium infusion increased both regional and global M, by 71 + 19% and 65 + 9%, respectively (p < .02), with no significant change in LW. To normalize for ventricular geometry and heart rate, stroke work was computed from circumferential stress-strain data and converted to myocardial power output, which was then plotted against enddiastolic circumferential strain. This relationship also was highly linear, and the slope, Mmp (mW/cm3 of myocardium), is proposed as a potential measure of intrinsic myocardial performance independent of loading, geometry, and heart rate. Circulation 71, No. 5, 994-1009, 1985 QUANTIFICATION of cardiac function has been the goal of physiologists for nearly a century, but it has been difficult if not impossible to establish practical or reliable measures of intrinsic myocardial performance in the intact heart. Some indexes, such as ventricular function curves relating stroke work to filling pressures, were nonlinear and difficult to quantify.' Other parameters suffered from lack of preload or afterload From the

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Section: Methodsmentioning

confidence: 99%

Linearity of the Frank-Starling relationship in the intact heart: the concept of preload recruitable stroke work.

Glower¹,

Spratt²,

Snow³

et al. 1985

Circulation

813

420

View full text Add to dashboard Cite

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“…More complex models can be considered as well, see e.g. [173]. Coupling with the circulation is mediated by valves, whose behavior cannot be described by the elementary components depicted in Fig.…”

Section: From An Arterial Tract To a Compartmentmentioning

confidence: 99%

Geometric multiscale modeling of the cardiovascular system, between theory and practice

Quarteroni

Veneziani

Vergara

2016

Computer Methods in Applied Mechanics and Engineering

169

157

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This review paper addresses the so called geometric multiscale approach for the numerical simulation of blood flow problems, from its origin (that we can collocate in the second half of '90s) to our days. By this approach the blood fluid-dynamics in the whole circulatory system is described mathematically by means of heterogeneous featuring different degree of detail and different geometric dimension that interact together through appropriate interface coupling conditions.Our review starts with the introduction of the stand-alone problems, namely the 3D fluidstructure interaction problem, its reduced representation by means of 1D models, and the so-called lumped parameters (aka 0D) models, where only the dependence on time survives. We then address specific methods for stand-alone 3D models when the available boundary data are not enough to ensure the mathematical well posedness. These so-called "defective problems" naturally arise in practical applications of clinical relevance but also because of the interface coupling of heterogeneous problems that are generated by the geometric multiscale process. We also describe specific issues related to the boundary treatment of reduced models, particularly relevant to the geometric multiscale coupling. Next, we detail the most popular numerical algorithms for the solution of the coupled problems. Finally, we review some of the most representative works -from different research groups -which addressed the geometric multiscale approach in the past years.A proper treatment of the different scales relevant to the hemodynamics and their interplay is essential for the accuracy of numerical simulations and eventually for their clinical impact. This paper aims at providing a state-of-the-art picture of these topics, where the gap between theory and practice demands rigorous mathematical models to be reliably filled.

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“…The velocity axis can often be disregarded without serious loss of information in the analysis of the performance of the intact heart. The ventricular pressure-volume relationship (133,286,324,347) is useful for analysis and links muscle mechanics and ventricular function. Contractile state is defined as the maximal tension or pressure that can be developed at any given fiber length or volume.…”

Section: Cardiac Dimensions and Pump Performancementioning

confidence: 99%