Modeling ventricular contraction with heart rate changes

Ottesen, Johnny T.; Danielsen, M.

doi:10.1016/s0022-5193(03)00040-7

Cited by 56 publications

(39 citation statements)

References 6 publications

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“…In the present study, an empirical sigmoidal function [31] was employed to relate the moment of peak systolic elastance to a cardiac cycle. The mathematical description is shown below: (10) where Values of the coefficients in the heart model can be found in Table 1.…”

Section: (Ii) Left-right Ventricular Interactionmentioning

confidence: 99%

“…Experimental data on inertance at vascular levels detailing the arteriolar, capillary, and venule beds have been merely reported. In fact, data available in literature were usually limited to some big arteries or veins [4,10,31]. Although inertance has almost no effect on steady blood flow, it may be a parameter affecting the shape of time-dependent flow waveforms, especially the reversal of arterial flow in early diastole.…”

Section: (Ii) Left-right Ventricular Interactionmentioning

confidence: 99%

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Simulation of Hemodynamic Responses to the Valsalva Maneuver: An Integrative Computational Model of the Cardiovascular System and the Autonomic Nervous System

Liang

Líu

2006

J. Physiol. Sci

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Abstract:The Valsalva maneuver is a frequently used physiological test in evaluating the cardiovascular autonomic functions in human. Although a large pool of experimental data has provided substantial insights into different aspects of the mechanisms underlying the cardiovascular regulations during the Valsalva maneuver, so far a complete comprehension of these mechanisms and the interactions among them is unavailable. In the present study, a computational model of the cardiovascular system (CVS) and its interaction with the autonomic nervous system (ANS) was developed for the purpose of quantifying the individual roles of the CVS and the ANS in the hemodynamic regulations during the Valsalva maneuver. A detailed computational compartmental parameter model of the global CVS, a system of mathematical equations representing the autonomic nervous reflex regulatory functions, and an empirical cerebral autoregulation (CA) model formed the main body of the present model. Based on simulations of the Valsalva maneuvers at several typical postures, it was demonstrated that hemodynamic responses to the maneuver were not only determined by the ANSmediated cardiovascular regulations, but also significantly affected by the postural-change-induced hemodynamic alterations preceding the maneuver. Moreover, the large-magnitude overshoot in cerebral perfusion immediately after the Valsalva maneuver was found to result from a combined effect of the circulatory autonomic functions, the CA, and the cerebral venous blood pressure.Key words: computational model, cardiovascular system, autonomic nervous system, Valsalva maneuver.The Valsalva maneuver, first described by the Italian anatomist Antonio Maria Valsalva in 1704 [1], entails straining against a closed glottis by forcefully constricting the chest muscles, which as a consequence will lead to a marked elevation of intrathoracic pressure. Such an increase in this pressure will largely impede venous return, subsequently reduce cardiac output, and ultimately result in a rapid fall in arterial blood pressure that will seriously challenge the cardiovascular nervous reflex regulatory functions. In literature, many experimental results have been presented concerning the mechanisms by which the cardiovascular and autonomic nervous systems respond to the Valsalva maneuver. Nevertheless, most of these experiments have until now been conducted with emphases on some limited aspects of the hemodynamic regulations. A comprehensive understanding of the mechanisms underlying the Valsalva maneuver remains unobtainable simply by experimental studies. At this point, an integrative mathematical model representing the hemodynamics of the whole CVS along with the regulatory functions of the ANS can serve as a useful adjunct for in vivo experiments. This model may provide a rational framework that quantitatively defines interactions among many cardiovascular and nervous reflex regulatory parameters and supports the critical interpretation of experimental results and the testing of hypotheses.From the...

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Section: (Ii) Left-right Ventricular Interactionmentioning

confidence: 99%

Section: (Ii) Left-right Ventricular Interactionmentioning

confidence: 99%

Simulation of Hemodynamic Responses to the Valsalva Maneuver: An Integrative Computational Model of the Cardiovascular System and the Autonomic Nervous System

Liang

Líu

2006

J. Physiol. Sci

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“…Figure 1 shows the arterial circulation model made of two parts, the LV pump and the arterial system analog circuit. The left ventricle (LV) is handled as a pressure source that depends on time (t), ventricular volume (V v ), outflow (Q v ) and heart rate (H), which provides a direct coupling with the varying vascular conditions [11,12]. By coupling this ventricular pump model with a Windkessel afterload, the main variables of the arterial circulation can be numerically simulated, including the aortic valve opening and closure times.…”

Section: Relationship Between Abp and Pepmentioning

confidence: 99%

“…where the activation function F(t,Q v ,H) includes specific ejection effects depending on the outflow Q v [11] and a cardiac force-frequency relation derived from experimental canine data [12]. All LV model parameters have a physiological meaning e.g., c is the main contractility parameter.…”

Section: Description Of the Cardiac-arterial Modelmentioning

confidence: 99%

A model-based study of the influence of vaso-active drugs on pulse delays measured from the electrocardiogram

Aubert

Muehlsteff

2007

2007 Computers in Cardiology

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The use of ECG-based IntroductionNon-invasive measurements of pulse wave velocity (PWV) or pulse transit time (PTT) have been studied for more than 30 years [1] as possible surrogate of the arterial blood pressure (ABP), with the aim of replacing the uncomfortable and intermittent cuff method. A number of papers have questioned the usefulness of pulse delays measured from the ECG as a marker of ABP, especially when the subject has been administered vasoactive drugs [2][3][4][5][6]. In this paper, elements of explanation are proposed, based on mathematical models of the arterial circulation and pulse wave propagation.Vaso-active drugs (VAD) are widely used in the management of cardio-vascular diseases, especially during decompensation phases. Their main effect is to alter the systemic vascular resistance (SVR) with little impact on the frequency and intensity of cardiac contractions, depending on the type and dosage of the used VAD.When measuring the delay of pulse arrival time (PAT) at periphery from the ECG QRS complex, two distinct time intervals are actually summed up: the pre-ejection period (PEP) and the vascular PTT. The PEP covers the iso-volumic contraction phase up to the aortic valve opening while PTT represents the pulse propagation time along the arterial wall up to the chosen peripheral site. Both terms do carry significant beat-to-beat information about the ABP, however, of quite different nature and time dynamics [2,7] while the observed PAT values consist of their sum only.The inverse dependency of PTT on the transmural pressure is established by the Moens-Korteweg equation coupled with Hughes' non-linear elasticity-pressure relationship [8]. However, there is a lack of knowledge about the inter-dependencies of PEP and ABP [9]. In this work, a lumped model of the arterial circulation is exploited to compute dependence curves of PEP on ABP when varying hemodynamic parameters like the peripheral resistance and left-ventricular (LV) contractility [10]. Simulation results indicate that PEP varies either directly or inversely with the ABP, depending on the changes occurring to the cardio-vascular status. When the peripheral resistance changes, the PEP shows a direct correlation with the ABP, opposite to the inverse PTT dependency. Hence, PAT becomes an unreliable marker of ABP because the changes of PTT may be offset or even largely obliterated by opposite PEP variations.In section 2 previous work having addressed the impact of VAD on pulse delays is briefly reviewed. Section 3 explains the main equations and model used to derive the relationships of either PTT or PEP with the ABP. Section 4 presents the computed dependence curves of PEP on the ABP as well as examples of systolic blood pressure (SBP) predictions for real-life recordings in the intensive care unit (ICU), drawn from the MIMIC database. These results and their limitations are discussed in section 5. Brief overview of previous workFour papers published from 1983 to 2006 are examined, each one dealing with the influence of vaso-...

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“…They generated a loop diagram from these surrogate parameters with which they could estimate LV contractility. In the years 2001-2003 the mathematicians Danielsen, Ottesen and Paladino (4)(5)(6) from the University of Roskilde published a model equation from which we deduce that, with simplified assumptions, the Doppler sonographic arterial flow would have to change in proportion to pressure and we asked ourselves if contractility could also be estimated with a flow-area relationship.…”

Section: Introductionmentioning

confidence: 99%

Measurement of Myocardial Contractility in the Ischemic Heart – A Disease Immanent Uncertainty

Broscheit¹

2012

Novel Strategies in Ischemic Heart Disease

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Modeling ventricular contraction with heart rate changes

Cited by 56 publications

References 6 publications

Simulation of Hemodynamic Responses to the Valsalva Maneuver: An Integrative Computational Model of the Cardiovascular System and the Autonomic Nervous System

Simulation of Hemodynamic Responses to the Valsalva Maneuver: An Integrative Computational Model of the Cardiovascular System and the Autonomic Nervous System

A model-based study of the influence of vaso-active drugs on pulse delays measured from the electrocardiogram

Measurement of Myocardial Contractility in the Ischemic Heart – A Disease Immanent Uncertainty

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