scholarly journals Phenotyping heart failure using model-based analysis and physiology-informed machine learning

2021 ◽  
Author(s):  
Edith Jones ◽  
E. Benjamin Randall ◽  
Scott L. Hummel ◽  
David Cameron ◽  
Daniel A. Beard ◽  
...  
Keyword(s):  
Heart Failure ◽  
Cardiovascular System ◽  
Specific Treatment ◽  
Left Ventricular ◽  
Patient Specific ◽  
Health Improvement ◽  
Model Parameters ◽  
Loop Model ◽  
Improvement Project ◽  
Model Based

AbstractTo determine the underlying mechanistic differences between diagnoses of Heart Failure (HF) and specifically heart failure with reduced and preserved ejection fraction (HFrEF & HFpEF), a closed loop model of the cardiovascular system coupled with patient specific transthoracic echocardiography (TTE) and right heart catheterization (RHC) measures was used to identify key parameters representing cardiovascular hemodynamics. Thirty-one patient records (10 HFrEF, 21 HFpEF) were obtained from the Cardiovascular Health Improvement Project (CHIP) database at the University of Michigan. Model simulations were tuned to match RHC and TTE pressure, volume and cardiac output measures in each patient with average error between data and model of 4.87 ± 2%. The underlying physiological model parameters were then plotted against model-based norms and compared between the HFrEF and HFpEF group. Our results confirm that the main mechanistic parameter driving HFrEF is reduced left ventricular contractility, while for HFpEF a much wider underlying phenotype is presented. Conducting principal component analysis (PCA), k-means, and hierarchical clustering on the optimized model parameters, but not on clinical measures, shows a distinct group of HFpEF patients sharing characteristics with the HFrEF cohort, a second group that is distinct as HFpEF and a group that exhibits characteristics of both. Significant differences are observed (p-value<.001) in left ventricular active contractility and left ventricular relaxation, when comparing HFpEF patients to those grouped as similar to HFrEF. These results suggest that cardiovascular system modeling of standard clinical data is able to phenotype and group HFpEF as different subdiagnoses, possibly elucidating patient-specific treatment strategies.

Cardiac Resynchronisation Therapy – Evolving Strategies to Enhance Response

2010 ◽  
Vol 6 (1) ◽  
pp. 83
Author(s):  
Jagmeet P Singh ◽  
Keyword(s):  
Heart Failure ◽  
Systolic Heart Failure ◽  
Cardiac Resynchronisation Therapy ◽  
Left Ventricular ◽  
Patient Specific ◽  
Cardiac Resynchronisation ◽  
Clinical Benefits ◽  
Pacing Lead ◽  
Resynchronisation Therapy ◽  
Physiological Impact

Cardiac resynchronisation therapy (CRT) has gained widespread acceptance as a safe and effective therapeutic strategy for congestive heart failure (CHF) refractory to optimal medical therapy. The use of implantable devices has substantially altered the natural history of systolic heart failure. These devices exert their physiological impact through ventricular remodelling, associated with a reduction in left ventricular (LV) volumes and an improvement in ejection fraction (EF). Several prospective randomised studies have shown that this in turn translates into long-term clinical benefits such as improved quality of life, increased functional capacity and reduction in hospitalisation for heart failure and overall mortality. Despite these obvious benefits, there remain more than a few unresolved concerns, the most important being that up to one-third of patients treated with CRT do not derive any detectable benefit. There are several determinants of successful delivery and response to CRT, including selecting the appropriate patient, patient-specific optimal LV pacing lead placement and appropriate post-implant device care and follow-up. This article highlights the importance of collectively working on all of these aspects of CRT to enhance and maximise response.

scholarly journals The effect of beta-blockers on hemodynamic parameters in patient-specific blood flow simulations of type-B aortic dissection: a virtual study

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mohammad Amin Abazari ◽  
Deniz Rafieianzab ◽  
M. Soltani ◽  
Mona Alimohammadi
Keyword(s):  
Aortic Dissection ◽  
Clinical Decision Making ◽  
Beta Blockers ◽  
False Lumen ◽  
Specific Treatment ◽  
Left Ventricular ◽  
Patient Specific ◽  
Type B ◽  
Windkessel Model ◽  
Computed Tomography Images

AbstractAortic dissection (AD) is one of the fatal and complex conditions. Since there is a lack of a specific treatment guideline for type-B AD, a better understanding of patient-specific hemodynamics and therapy outcomes can potentially control the progression of the disease and aid in the clinical decision-making process. In this work, a patient-specific geometry of type-B AD is reconstructed from computed tomography images, and a numerical simulation using personalised computational fluid dynamics (CFD) with three-element Windkessel model boundary condition at each outlet is implemented. According to the physiological response of beta-blockers to the reduction of left ventricular contractions, three case studies with different heart rates are created. Several hemodynamic features, including time-averaged wall shear stress (TAWSS), highly oscillatory, low magnitude shear (HOLMES), and flow pattern are investigated and compared between each case. Results show that decreasing TAWSS, which is caused by the reduction of the velocity gradient, prevents vessel wall at entry tear from rupture. Additionally, with the increase in HOLMES value at distal false lumen, calcification and plaque formation in the moderate and regular-heart rate cases are successfully controlled. This work demonstrates how CFD methods with non-invasive hemodynamic metrics can be developed to predict the hemodynamic changes before medication or other invasive operations. These consequences can be a powerful framework for clinicians and surgical communities to improve their diagnostic and pre-procedural planning.

scholarly journals Evaluating the Hemodynamical Response of a Cardiovascular System under Support of a Continuous Flow Left Ventricular Assist Device via Numerical Modeling and Simulations

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Selim Bozkurt ◽  
Koray K. Safak
Keyword(s):  
Heart Failure ◽  
Cardiovascular System ◽  
Left Ventricular Assist Device ◽  
Ventricular Assist Device ◽  
Continuous Flow ◽  
Left Ventricular ◽  
Circulatory Support ◽  
Assist Device ◽  
Ventricular Assist ◽  
Left Ventricular Assist

Dilated cardiomyopathy is the most common type of the heart failure which can be characterized by impaired ventricular contractility. Mechanical circulatory support devices were introduced into practice for the heart failure patients to bridge the time between the decision to transplant and the actual transplantation which is not sufficient due to the state of donor organ supply. In this study, the hemodynamic response of a cardiovascular system that includes a dilated cardiomyopathic heart under support of a newly developed continuous flow left ventricular assist device—Heart Turcica Axial—was evaluated employing computer simulations. For the evaluation, a numerical model which describes the pressure-flow rate relations of Heart Turcica Axial, a cardiovascular system model describing the healthy and pathological hemodynamics, and a baroreflex model regulating the heart rate were used. Heart Turcica Axial was operated between 8000 rpm and 11000 rpm speeds with 1000 rpm increments for assessing the pump performance and response of the cardiovascular system. The results also give an insight about the range of the possible operating speeds of Heart Turcica Axial in a clinical application. Based on the findings, operating speed of Heart Turcica Axial should be between 10000 rpm and 11000 rpm.

In vivo application and validation of a novel non-invasive method to estimate the end-systolic elastance

2021 ◽  
Author(s):  
Stamatia Pagoulatou ◽  
Karl-Philipp Rommel ◽  
Karl-Patrik Kresoja ◽  
Maximilian von Roeder ◽  
Philipp Lurz ◽  
...  
Keyword(s):  
Heart Failure ◽  
Systolic Function ◽  
Cuff Pressure ◽  
Left Ventricular ◽  
Aortic Flow ◽  
Arterial System ◽  
Patient Specific ◽  
Correct Prediction ◽  
Non Invasive ◽  
Cardiac Model

Accurate assessment of the left ventricular (LV) systolic function is indispensable in the clinic. However, estimation of a precise index of cardiac contractility, i.e., the end-systolic elastance (Ees), is invasive and cannot be established as clinical routine. The aim of this work was to present and validate a methodology that allows for the estimation of Ees from simple and readily available non-invasive measurements. The method is based on a validated model of the cardiovascular system and non-invasive data from arm-cuff pressure and routine echocardiography to render the model patient-specific. Briefly, the algorithm first uses the measured aortic flow as model input and optimizes the properties of the arterial system model in order to achieve correct prediction of the patient's peripheral pressure. In a second step, the personalized arterial system is coupled with the cardiac model (time-varying elastance model) and the LV systolic properties, including Ees, are tuned to predict accurately the aortic flow waveform. The algorithm was validated against invasive measurements of Ees (multiple pressure-volume loop analysis) taken from n=10 heart failure patients with preserved ejection fraction and n=9 patients without heart failure. Invasive measurements of Ees (median 2.4 mmHg/mL, range [1.0, 5.0] mmHg/mL) agreed well with method predictions (nRMSE=9%, ρ=0.89, bias=-0.1 mmHg/mL and limits of agreement [-0.9, 0.6] mmHg/mL). This is a promising first step towards the development of a valuable tool that can be used by clinicians to assess systolic performance of the LV in the critically ill.

scholarly journals Stochastic Modeling and Dynamic Analysis of the Cardiovascular System with Rotary Left Ventricular Assist Devices

2019 ◽  
Vol 2019 ◽  
pp. 1-18 ◽  
Author(s):  
Jeongeun Son ◽  
Dongping Du ◽  
Yuncheng Du
Keyword(s):  
Heart Failure ◽  
Cardiac Output ◽  
Pump Power ◽  
Aortic Valve ◽  
Cardiovascular System ◽  
Left Ventricular ◽  
Ventricular Assist Devices ◽  
Left Ventricular Assist Devices ◽  
Ventricular Assist ◽  
Left Ventricular Assist

Left ventricular assist devices (LVADs) have been used for end-stage heart failure patients as a therapeutic option. The aortic valve plays a critical role in heart failure and its treatment with a LVAD. The cardiovascular-LVAD model is often used to investigate the physiological demands required by patients and predict the hemodynamic of the native heart supported with a LVAD. As it is a “bridge-to-recovery” treatment, it is important to maintain appropriate and active dynamics of the aortic valve and the cardiac output of the native heart, which requires that the LVAD pump be adjusted so that a proper balance between the blood contributed through the aortic valve and the pump is maintained. In this paper, we investigate how the pump power of the LVAD pump can affect the dynamic behaviors of the aortic valve for different levels of activity and different severities of heart failure. Our objective is to identify a critical value of the pump power (i.e., breakpoint) to ensure that the LVAD pump does not take over the pumping function in the cardiovascular-pump system and share the ejected blood with the left ventricle to help the heart to recover. In addition, the hemodynamic often involves variability due to patients’ heterogeneity and the stochastic nature of the cardiovascular system. The variability poses significant challenges to understanding dynamic behaviors of the aortic valve and cardiac output. A generalized polynomial chaos (gPC) expansion is used in this work to develop a stochastic cardiovascular-pump model for efficient uncertainty propagation, from which it is possible to rapidly calculate the variance in the aortic valve opening duration and the cardiac output in the presence of variability. The simulation results show that the gPC-based cardiovascular-pump model is a reliable platform that can provide useful information to understand the effect of the LVAD pump on the hemodynamic of the heart.

Robust physiological control of rotary blood pumps for heart failure therapy

2018 ◽  
Vol 66 (9) ◽  
pp. 767-779 ◽  
Author(s):  
Daniel Rüschen ◽  
Sebastian Opitz ◽  
Philip von Platen ◽  
Leonie Korn ◽  
Steffen Leonhardt ◽  
...  
Keyword(s):  
Heart Failure ◽  
Cardiovascular System ◽  
Left Ventricular ◽  
Ventricular Assist Devices ◽  
Heart Failure Therapy ◽  
Physiological Control ◽  
Detailed Model ◽  
Blood Pumps ◽  
Rotary Blood Pumps ◽  
Varying Demand

Abstract Left ventricular assist devices (LVADs) have become a viable alternative to heart transplantation in heart failure therapy. In clinical practice, rotary blood pumps used as LVADs are operated at a constant rotational speed and thus do not adapt to the varying demand of the patient. This paper presents a robust control approach for automatic adaptation of the blood pump speed to the blood flow demand of the patient’s body, which enables a defined load sharing between an LVAD and the native ventricle. Robust stability was checked using a detailed model of the human cardiovascular system with uncertainties that describe the most important native physiological control loops as well as a range of pathologies. The robust assistance controller was tested in an in vivo setup and was able to stabilize the cardiovascular system after myocardial infarction.

scholarly journals An Autonomic Nervous System Model Applied to the Analysis of Orthostatic Tests

2008 ◽  
Vol 2008 ◽  
pp. 1-15 ◽  
Author(s):  
Virginie Le Rolle ◽  
Alfredo I. Hernández ◽  
Pierre-Yves Richard ◽  
Guy Carrault
Keyword(s):  
Heart Rate ◽  
Nervous System ◽  
Autonomic Nervous System ◽  
Cardiovascular Response ◽  
Patient Specific ◽  
Diabetic Patients ◽  
Model Parameters ◽  
Autonomic Nervous ◽  
Ventricular Mechanics ◽  
Model Based

One of the clinical examinations performed to evaluate the autonomic nervous system (ANS) activity is the tilt test, which consists in studying the cardiovascular response to the change of a patient's position from a supine to a head-up position. The analysis of heart rate variability signals during tilt tests has been shown to be useful for risk stratification and diagnosis on different pathologies. However, the interpretation of such signals is a difficult task. The application of physiological models to assist the interpretation of these data has already been proposed in the literature, but this requires, as a previous step, the identification of patient-specific model parameters. In this paper, a model-based approach is proposed to reproduce individual heart rate signals acquired during tilt tests. A new physiological model adapted to this problem and coupling the ANS, the cardiovascular system (CVS), and global ventricular mechanics is presented. Evolutionary algorithms are used for the identification of patient-specific parameters in order to reproduce heart rate signals obtained during tilt tests performed on eight healthy subjects and eight diabetic patients. The proposed approach is able to reproduce the main components of the observed heart rate signals and represents a first step toward a model-based interpretation of these signals.

scholarly journals Increased myocardial stiffness more than impaired relaxation function limits cardiac performance during exercise in heart failure with preserved ejection fraction: a virtual patient study

2020 ◽  
Vol 1 (1) ◽  
pp. 40-50
Author(s):  
Tim van Loon ◽  
Christian Knackstedt ◽  
Richard Cornelussen ◽  
Koen D Reesink ◽  
Hans-Peter Brunner La Rocca ◽  
...  
Keyword(s):  
Heart Failure ◽  
Ejection Fraction ◽  
Relaxation Function ◽  
Wide Spectrum ◽  
Virtual Patient ◽  
Left Ventricular ◽  
Filling Pressure ◽  
Patient Specific ◽  
Preserved Ejection Fraction ◽  
Passive Stiffness

Abstract Aims The relative impact of left ventricular (LV) diastolic dysfunction (LVDD) and impaired left atrial (LA) function on cardiovascular haemodynamics in heart failure with preserved ejection fraction (HFpEF) is largely unknown. We performed virtual patient simulations to elucidate the relative effects of these factors on haemodynamics at rest and during exercise. Methods and results The CircAdapt cardiovascular system model was used to simulate cardiac haemodynamics in wide ranges of impaired LV relaxation function, increased LV passive stiffness, and impaired LA function. Simulations showed that LV ejection fraction (LVEF) was preserved (&gt;50%), despite these changes in LV and LA function. Impairment of LV relaxation function decreased E/A ratio and mildly increased LV filling pressure at rest. Increased LV passive stiffness resulted in increased E/A ratio, LA dilation and markedly elevated LV filling pressure. Impairment of LA function increased E/A ratio and LV filling pressure, explaining inconsistent grading of LVDD using echocardiographic indices. Exercise simulations showed that increased LV passive stiffness exerts a stronger exercise-limiting effect than impaired LV relaxation function does, especially with impaired LA function. Conclusion The CircAdapt model enabled realistic simulation of virtual HFpEF patients, covering a wide spectrum of LVDD and related limitations of cardiac exercise performance, all with preserved resting LVEF. Simulations suggest that increased LV passive stiffness, more than impaired relaxation function, reduces exercise tolerance, especially when LA function is impaired. In future studies, the CircAdapt model can serve as a valuable platform for patient-specific simulations to identify the disease substrate(s) underlying the individual HFpEF patient’s cardiovascular phenotype.

scholarly journals The missing link- time to maximal rate of left ventricular pressure rise reflects resynchronization with biventricular pacing in patients with heart failure and left bundle branch block

EP Europace ◽  
2021 ◽  
Vol 23 (Supplement_3) ◽  
Author(s):  
H Odland ◽  
S Ross ◽  
LO Gammelsrud ◽  
R Cornelussen ◽  
E Kongsgard
Keyword(s):  
Heart Failure ◽  
Biventricular Pacing ◽  
Pressure Rise ◽  
Left Ventricular Pressure ◽  
Lateral Position ◽  
Left Ventricular ◽  
Cardiac Resynchronization ◽  
Patient Specific ◽  
Resynchronization Therapy ◽  
Missing Link

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Norwegian South East Health Authorities Introduction Resynchronization therapy effectively restores myocardial function. No measures exist that specifically quantifies resynchronization. A parameter that quantifies resynchronization should be able to detect effective resynchronization and should not respond to changes in contractility caused by heterometric regulation.  Left ventricular pacing (LVP) is associated with dyssynchronous contraction patterns, while biventricular pacing (BIVP) promotes resynchronization dependent on the pacing position of the LV electrode. Purpose We compared the acute differences between BIVP and LVP with regards to the preload dependent maximum rate of the LV pressure rise (dP/dtmax), and time to peak dP/dt (Td) to determine which better reflect dyssynchrony and resynchronization. Methods Twenty nine patients in heart failure with LBBB underwent CRT implantation with continuous LV pressure registration. The LV lead was first placed in either apical or anterior position followed by a permanent placement in a lateral position. Sequential LVP and BIVP pacing were performed for one minute, at a rate 10% above intrinsic heart rate, before dP/dtmax measurements were recorded. For LVP, BIVP and RVP a patient specific AV delay was used to avoid fusion with intrinsic conduction. Td was defined as the time from pacemaker stimuli to peak dP/dt. Mixed linear models were used for statistics, numbers are estimated marginal means ± SEM and are only reported when with significance set at p &lt; 0.05. Results We found no differences in dP/dtmax between BIVP (899 ± 37mmHg/s) and LVP (910 ± 37mmHg/s), while RVP (799 ± 37mmHg/s) was lower. Td was lower with BIVP (165 ± 4ms) than LVP (178 ± 4ms) and RVP (184 ± 4ms).  We found no differences in dP/dtmax between lateral (890 ± 35mmHg/s) and anterior (874 ± 38mmHg/s) while apical (824 ± 38mmHg/s) was lower. Td was lower in lateral (171 ± 4ms) than in anterior (179 ± 4ms) and apical (182 ± 4ms) positions. BIVP in lateral position (158 ± 4ms) was lower than any other pacingmode*position, with BIVP*anterior at 173 ± 4ms) and LVP*lateral at 170 ± 2ms. No difference was seen in dP/dtmax between  (BIVP + LVP)*(lateral + anterior) that was higher than all other pacingmode*positions. Conclusion Td shortens with BIVP and lateral position, and even more so with BIVP in lateral position and thus reflects resynchronization compared to all other combinations tested. DP/dtmax did not reflect resynchronization as BIVP/LVP and lateral/anterior performs equally good. There are no differences between dP/dtmax with any combination of pacing mode (BIVP + LVP) with position (anterior + lateral). This suggests that Td reflects resynchronization while dP/dtmax does not. Resynchronization with biventricular pacing in lateral position translates into a shorter Td and hence links electrical and mechanical events. Td could be the missing link between electrical and mechanical dyssynchrony and may serve as a biomarker for cardiac resynchronization therapy.

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