Ventricular Ejection Fraction and Global Strains in Connection with the Volume Regulation Graph.

Ejection fraction (EF) is traditionally considered useful to infer ventricular function. Newer metrics such as global function index (GFI) and various strains add supplemental diagnostic or prognostic value. All these candidates refer to dimensionless ratios, rather than to the characteristics of the underlying components.

Sex-specific Evaluation of Ventricular Ejection Fraction and End-Systolic Volume Applied to Cardiac Resynchronization Therapy.

Cardiac resynchronization therapy (CRT) can decrease the risk of heart failure (HF) events in relatively asymptomatic patients with a reduced ejection fraction (EF) and wide QRS complex. However, individual response to this type of therapy varies widely. Often based on either EF increase or end-systolic volume (ESV) decrease as criterion, a subgroup of super-responders has been described.

Pulse Pressure is Sex-Specifically Associated with the Ratio of Diastolic and Systolic Arterial Pressure in Healthy Children, and Differently During Night Versus Daytime Recordings.

Noninvasive blood pressure recordings typically focus on systolic blood pressure (SBP) and diastolic pressure (DBP). Derived metrics are often analyzed, e.g.

Various Approaches to Define the Volume Intercept of the Ventricular End-Systolic Pressure-Volume Relationship: Implications for Statistical Analysis.

Ventricular pump function is often characterized by the (non)linear end-systolic pressure-volume relationship (ESPVR). For each working point on that curve the tangent along with the intercept (Vo) reflect contractile state. Vo on the abscissa is an extrapolated point without physiological meaning, and may be negative.

The Ratio of Diastolic and Systolic Arterial Pressure is Associated with Pulse Pressure.

Pulse pressure (PP) is defined as the difference between systolic blood pressure (SBP) and diastolic blood pressure (DBP). The metric PP is not unique, as numerous combinations of SBP and DBP yield the same value for PP. Therefore, we introduced the PP companion (PPC) which is calculated using the Pythagorean theorem.

Machine Learning-Based Continuous Intracranial Pressure Prediction for Traumatic Injury Patients.

: Abnormal elevation of intracranial pressure (ICP) can cause dangerous or even fatal outcomes. The early detection of high intracranial pressure events can be crucial in saving lives in an intensive care unit (ICU). Despite many applications of machine learning (ML) techniques related to clinical diagnosis, ML applications for continuous ICP detection or short-term predictions have been rarely reported.

Inadequacy of Augmentation Index for Monitoring Arterial Stiffness: Comparison with Arterial Compliance and Other Hemodynamic Variables.

Purpose: Augmentation Index (AI) is used clinically for monitoring both wave reflections and arterial stiffness, which when increased is a risk factor of cardiovascular mortality and morbidity. We hypothesize that AI is not solely related to vascular stiffness as described by arterial compliance and other hemodynamic parameters since AI underestimates wave reflections.

Methods: Aortic pressure and flow datasets (n = 42) from mongrel dogs were obtained from our experiments and Mendeley Data under various conditions.

Polar Coordinate Description of Blood Pressure Measurements and Implications for Sex-Specific and Personalized Analysis.

Vascular properties and their associated impact on cardiovascular risk factors are often evaluated by metrics such as pulse pressure (PP) and the augmentation index (AIx). All derived metrics are essentially based on the combination of blood pressure recordings. These clinically used metrics typically concern a difference (as in PP) or a ratio (as in AIx).

Augmentation index in the assessment of wave reflections and systolic loading.

Background: Augmentation index (AI) is used to quantify the augmented systolic aortic pressure that impedes ventricular ejection. Its use as an index of wave reflections is questionable. We hypothesize that AI is quantitatively different from the reflection coefficient under varied physiological conditions.

Investigation into the diversity in the fractal dimensions of arterioles and venules in a microvascular network - A quantitative analysis.

Fractal dimension is a robust fractal parameter for estimating the morphology of vascular networks. It reflects the property of vascular networks that may vary and thus, differentiate between individual networks and/or identify physiological and pathological conditions. As such, fractal dimension differs also between arteriolar and venular compartments, yet the underlying reason is so far unclear.

Myocardial oxygen balance during acute normovolemic hemodilution: A novel compartmental modeling approach.

Background: Hemodilution was introduced initially as a blood conservation technique to reduce allogeneic blood transfusion in patients undergoing surgical procedures. Although the technique has been approved by the National Institute of Health consensus panel, limits of hemodilution under anesthetic conditions have not been established as they have in animal models.

Methods: A novel multi-compartmental modeling approach has been proposed that includes the effect of anesthesia to quantify the effect of hemodilution on myocardial oxygen balance during myocardial ischemia.

Energetically wasteful wave reflections due to impedance mismatching in hypertension and their reversal with vasodilator: Time and frequency domain evaluations.

Background: Increased pulse wave reflections in hypertension arise due to impedance mismatching and the effective energy transmission to the vasculature is compromised. Their quantification in the time and the frequency domains are compared and the beneficial effect of vasodilator is evaluated in the study.

Methods: A simple, fast time domain method for the resolution of aortic pressure and flow pulses into their forward and reflected components is presented, together with frequency domain reflection coefficient and impedance calculations.

Quantitative cardiology and computer modeling analysis of heart failure in systole and in diastole.

Clinical cardiology diagnosis relies on the assessment of a set of specified parameters. Computer modeling is a powerful tool that can provide a realistic interpretation of the variations of these parameters through computational quantification. Here we present an overview of different aspects of diagnosis that are based on evaluation of either systolic or diastolic cardiac abnormalities.

Arterial Wall Properties in Men and Women: Hemodynamic Analysis and Clinical Implications.

The properties of arterial walls are dictated by their underlying structure, which is responsible for the adequate perfusion of conduit branching arteries and their vascular beds. Beginning with the mechanobiology of arteries in terms of their composition and individual contributions to overall viscoelastic behavior in men and women, pressure-flow relations are analyzed and noted in terms of sex differences. Hemodynamic function in terms of indices of vascular stiffness-such as pressure-strain elastic modulus, pulse wave velocity, augmentation index, and cardio-ankle vascular index-are evaluated.

Cardiovascular Allometry: Analysis, Methodology, and Clinical Applications.

The classic works of "On Growth and Form" and "The Problem of Relative Growth" that began a century ago have so fittingly, albeit unintentionally, become pertinent to the modern-day clinical treatment strategy of the many patients with cardiovascular disease. This chapter uses allometry, which was established for comparative biology, to explore physiological and pathological differences due to differential growth, which may lead to differing diagnostic and treatment approaches for male versus female patients. Men and women have obvious differences in body and heart weights, as well as different geometries and structures of their blood vessels; the analysis in this chapter extends to their hemodynamic functional differences.

Arterial Flow, Pulse Pressure and Pulse Wave Velocity in Men and Women at Various Ages.

The increase in pulse pressure (PP) that occurs with advancing age is predominantly due to reduced arterial distensibility leading to decreased aortic compliance, particularly in the elderly, in whom high blood pressure mainly manifests as isolated systolic hypertension. Since age-related changes in stroke volume are minimal compared with changes in PP, PP is often considered a surrogate measure of arterial stiffness. However, since PP is determined by both cardiac and arterial function, a more precise and reliable means of assessment of arterial stiffness is arterial pulse wave velocity (PWV), a parameter that is only dependent on arterial properties.

A novel compliance-pressure loop approach to quantify arterial compliance in systole and in diastole.

Arterial compliance has been recognized as a critical parameter in governing pulsatile flow dynamics. It has traditionally been assumed constant throughout the cardiac cycle and its computation has been based either on the classic Windkessel model (C) in diastole or the stroke volume over pulse pressure (C) method in systole. Other methods using area (C) or two-area (C) and exponential (C(P)) methods were used for the cardiac cycle.

Development and Retrospective Clinical Assessment of a Patient-Specific Closed-Form Integro-Differential Equation Model of Plasma Dilution.

A closed-form integro-differential equation (IDE) model of plasma dilution (PD) has been derived which represents both the intravenous (IV) infusion of crystalloid and the postinfusion period. Specifically, PD is mathematically represented using a combination of constant ratio, differential, and integral components. Furthermore, this model has successfully been applied to preexisting data, from a prior human study, in which crystalloid was infused for a period of 30 minutes at the beginning of thyroid surgery.

Validation of a novel nonlinear black box Wiener System model for arterial pulse transmission.

Numerous linear dynamic models exist for describing the arterial pulse transmission phenomenon. We introduce a novel Wiener system based model in which a linear filter representing large arteries is coupled with a hysteresis-free nonlinear function representing complex wave transmission of branching arteries and the periphery. Experimental datasets (n = 7) are used to first estimate the Wiener model with linear, quadratic and cubic function for the aorta to radial artery pulse transmission and aorta to femoral artery pulse transmission.

Modeling of pulsatile flow-dependent nitric oxide regulation in a realistic microvascular network.

Hemodynamic pulsatility has been reported to regulate microcirculatory function. To quantitatively assess the impact of flow pulsatility on the microvasculature, a mathematical model was first developed to simulate the regulation of NO production by pulsatile flow in the microcirculation. Shear stress and pressure pulsatility were selected as regulators of endothelial NO production and NO-dependent vessel dilation as feedback to control microvascular hemodynamics.

Aortic Pressure Estimation Using Blind Identification Approach on Single Input Multiple Output Nonlinear Wiener Systems.

Aortic pressure () is important for diagnosis of cardiovascular diseases, but it cannot be directly measured by noninvasive means. We present a method for its estimation by modeling arterial system as multichannel Weiner system with linear finite impulse response filter accounting for larger arteries transmission channel and nonlinear memoryless function block accounting for all nonlinearities due to narrowing of arteries, branching and visco-elastic forces. With this structure when pressure waveforms are measured from two distinct peripheral locations, multichannel blind system identification (MBSI) technique can be used to estimate common input pressure signal or .

Aging is Associated With an Earlier Arrival of Reflected Waves Without a Distal Shift in Reflection Sites.

Background: Despite pronounced increases in central pulse wave velocity (PWV) with aging, reflected wave transit time (RWTT), traditionally defined as the timing of the inflection point (TINF) in the central pressure waveform, does not appreciably decrease, leading to the controversial proposition of a "distal-shift" of reflection sites. TINF, however, is exceptionally prone to measurement error and is also affected by ejection pattern and not only by wave reflection. We assessed whether RWTT, assessed by advanced pressure-flow analysis, demonstrates the expected decline with aging.

Misinterpretation of the Determinants of Elevated Forward Wave Amplitude Inflates the Role of the Proximal Aorta.

Background: The hemodynamic basis for increased pulse pressure (PP) with aging remains controversial. The classic paradigm attributes a predominant role to increased pulse wave velocity (PWV) and premature wave reflections (WRs). A controversial new paradigm proposes increased forward pressure wave amplitude (FWA), attributed to proximal aortic characteristic impedance (Zc), as the predominant factor, with minor contributions from WRs.

Hemodynamic determinants and ventriculo-arterial coupling are sex-associated in heart failure patients.

End-systolic volume (ESV) and end-diastolic volume (EDV) are key parameters in the analysis of left ventricular (LV) function, and the study of cardiac remodeling. The volume regulation graph (VRG) relates these fundamental determinants, and permits convenient stratification for clinically relevant covariates. This contribution analyzes sex-associated differences in hemodynamic parameters for 197 heart failure (HF) patients, evaluated by biplane ventriculography, in combination with arterial pressure.