Anton J Prassl

Medical University of Graz · Institute of Biophysics

Background Substrate assessment of scar-mediated ventricular tachycardia (VT) is frequently performed using late gadolinium enhancement (LGE) images. Although this provides structural information about critical pathways through the scar, assessing the vulnerability of these pathways for sustaining VT is not possible with imaging alone. This study e...

Funding Acknowledgements Type of funding sources: Foundation. Main funding source(s): EACVI, Netherlands Heart Institute. Background Implantable cardiac defibrillator (ICD) implantation can protect against sudden cardiac death (SCD) after a myocardial infarction. However, relatively few patients with an ICD experience a life-threatening arrhythmic...

Funding Acknowledgements Type of funding sources: Foundation. Main funding source(s): EACVI, Netherlands Heart Institute. Background MRI late gadolinium enhancement (LGE) images can provide novel insights about critical pathways through scar but does not assess the vulnerability of these pathways for sustaining scar-mediated ventricular tachycardi...

Funding Acknowledgements Type of funding sources: Public Institution(s). Main funding source(s): EACVI Research Grant Academy Van Leersum grant of the Academy Medical Sciences Fund (Royal Netherlands Academy of Arts & Sciences). Background Implantable cardiac defibrillator (ICD) implantation can protect against sudden cardiac death (SCD) after a m...

Funding Acknowledgements Type of funding sources: Public Institution(s). Main funding source(s): Netherlands Heart Institute Fellowship, CVON PREDICT2 Young Talent Program Background MRI late gadolinium enhancement (LGE) images can provide novel insights about critical pathways through scar but does not assess the vulnerability of these pathways f...

Funding Acknowledgements Type of funding sources: Public grant(s) – EU funding. Main funding source(s): This research has also received funding from the European Union’s Horizon 2020 research and innovation programme under the ERA-NET co-fund action No. 680969 (ERA-CVD SICVALVES) funded by the Austrian Science Fund (FWF), Grant I 4652-B to CMA. Thi...

Background The role of sex-specific electrophysiology in the development of lethal ventricular arrhythmia is poorly understood. Since female ventricles have a longer action potential duration (APD) than male ventricles, we hypothesized that female hearts are more vulnerable to sustained ventricular arrhythmia in the presence of known arrhythmogenic...

Computer models capable of representing the intrinsic personal electrophysiology (EP) of the heart in silico are termed virtual heart technologies. When anatomy and EP are tailored to individual patients within the model, such technologies are promising clinical and industrial tools. Regardless of their vast potential, few virtual technologies simu...

Background Thresholding based analysis of late gadolinium enhancement cardiac MRI (LGE-CMR) can create scar maps and identify corridors that might provide a reentrant substrate for ventricular tachycardia (VT). Current recommendations employ a full-width-at-half-maximum approach, effectively classifying areas with a pixel-signal-intensity (PSI) >40...

Personalized models of cardiac electrophysiology (EP) that match clinical observation with high fidelity, referred to as cardiac digital twins (CDTs), show promise as a tool for tailoring cardiac precision therapies. Building CDTs of cardiac EP relies on the ability of models to replicate the ventricular activation sequence under a broad range of c...

Cardiac digital twins (Cardiac Digital Twin (CDT)s) of human electrophysiology (Electrophysiology (EP)) are digital replicas of patient hearts derived from clinical data that match like-for-like all available clinical observations. Due to their inherent predictive potential, CDTs show high promise as a complementary modality aiding in clinical deci...

Background and objective: Cardiac electrophysiology is a medical specialty with a long and rich tradition of computational modeling. Nevertheless, no community standard for cardiac electrophysiology simulation software has evolved yet. Here, we present the openCARP simulation environment as one solution that could foster the needs of large parts o...

Background and Objective Cardiac electrophysiology is a medical specialty with a long and rich tradition of computational modeling. Nevertheless, no community standard for cardiac electrophysiology simulation software has evolved yet. Here, we present the openCARP simulation environment as one solution that could foster the needs of large parts of...

Computational models of the heart are increasingly being used in the development of devices, patient diagnosis and therapy guidance. While software techniques have been developed for simulating single hearts, there remain significant challenges in simulating cohorts of virtual hearts from multiple patients. To facilitate the development of new simu...

Computer models of left ventricular (LV) electro-mechanics (EM) show promise as a tool for assessing the impact of increased afterload upon LV performance. However, the identification of unique afterload model parameters and the personalization of EM LV models remains challenging due to significant clinical input uncertainties. Here, we personalize...

Aims: To assess, whether Culotte technique could be improved by an additional kissing dilation prior main branch (MB) stenting. Methods and results: Double-kissing (DK) Culotte was compared to Culotte and DK-Crush techniques in bench model (n=24). Results were evaluated for stent apposition, for luminal opening and for flow dynamics. Total proce...

The pericardium affects cardiac motion by limiting epicardial displacement normal to the surface. In computational studies, it is important for the model to replicate realistic motion, as this affects the physiological fidelity of the model. Previous computational studies showed that accounting for the effect of the pericardium allows for a more re...

Advanced cardiac modeling studies rely on the ability to generate and functionalize personalized in silico models from tomographic multi-label image stacks. Eventually, this is used for building virtual cohorts that capture the variability in size, shape, and morphology of individual hearts. Typical modeling workflows involve a multitude of interac...

Introduction: Stenotic aortic valve disease (AS) causes pressure overload of the left ventricle (LV) that may trigger adverse remodeling and precipitate progression towards heart failure (HF). As myocardial energetics can be impaired during AS, LV wall stresses and biomechanical power provide a complementary view of LV performance that may aide in...

Background: Arterial hypertension (HT) contributes to progression of atrial fibrillation (AF) via unknown mechanisms. Objective: We aimed to characterize electrical and structural changes accounting for increased AF stability in a large animal model of rapid atrial pacing (RAP)-induced AF combined with desoxycorticosterone acetate (DOCA)-induced...

Computational fluid dynamics (CFD) models of blood flow in the left ventricle (LV) and aorta are important tools for analyzing the mechanistic links between myocardial deformation and flow patterns. Typically, the use of image-based kinematic CFD models prevails in applications such as predicting the acute response to interventions which alter LV a...

Being able to map a particular set of cardiac ventricles to a generic topologically equivalent representation has many applications, including facilitating comparison of different hearts, as well as mapping quantities and structures of interest between them. In this paper we describe Universal Ventricular Coordinates (UVC), which can be used to des...

Anatomically accurate and biophysically detailed bidomain models of the human heart have proven a powerful tool for gaining quantitative insight into the links between electrical sources in the myocardium and the concomitant current flow in the surrounding medium as they represent their relationship mechanistically based on first principles. Such m...

Computer simulation turns out to be beneficial when clinical data lack spatio-temporal resolution or parameters cannot be measured at all. To derive trustworthy results, these in-silico models have to thoroughly parameterized and validated. In this work we present data from a simplified in-vitro setup for characterizing ventricular electromechanics...

Aims Models of blood flow in the left ventricle (LV) and aorta are an important tool for analysing the interplay between LV deformation and flow patterns. Typically, image-based kinematic models describing endocardial motion are used as an input to blood flow simulations. While such models are suitable for analysing the hemodynamic status quo, they...

Electromechanical (EM) models of the heart have been used successfully to study fundamental mechanisms underlying a heart beat in health and disease. However, in all modeling studies reported so far numerous simplifications were made in terms of representing biophysical details of cellular function and its heterogeneity, gross anatomy and tissue mi...

Computational models of cardiac electromechanics (EM) are increasingly being applied to clinical problems, with patient-specific models being generated from high fidelity imaging and used to simulate patient physiology, pathophysiology and response to treatment. Current structured meshes are limited in their ability to fully represent the detailed...

Aims Premature ventricular complexes (PVCs) due to spontaneous calcium (Ca) release (SCR) events at the cell level can precipitate ventricular arrhythmias. However, the mechanistic link between SCRs and PVC formation remains incompletely understood. The aim of this study was to investigate the conditions under which delayed afterdepolarizations res...

Advanced medical imaging technologies provide a wealth of information on cardiac anatomy and structure at a paracellular resolution, allowing to identify microstructural discontinuities which disrupt the intracellular matrix. Current state-of-the-art computer models built upon such datasets account for increasingly finer anatomical details, however...

We present an approach to model the dispersion of fiber and sheet orientations in the myocardium. By utilizing structure parameters, an existing orthotropic and invariant-based constitutive model developed to describe the passive behavior of the myocardium is augmented. Two dispersion parameters are fitted to experimentally observed angular dispers...

Driven by recent advances in medical imaging, image segmentation and numerical techniques, computer models of ventricular electrophysiology account for increasingly finer levels of anatomical and biophysical detail. However, considering the large number of model parameters involved parameterization poses a major challenge. A minimum requirement in...

Computational modeling of ventricular electromechanics is considered to be among the most promising approaches to gain novel insight into cardiac function in health and disease. Such models allow to integrate the wealth of available experimental data into a mechanistic framework which allows to study complex cause-effect relationships across severa...

At any point in space the material properties of the myocardium are characterized as orthotropic, that is, there are three mutually orthogonal axes along which both electrical and mechanical parameters differ. To investigate the role of spatial structural heterogeneity in an orthotropic material, electro-mechanically coupled models of the left vent...

Driven by recent advances in medical imaging, image segmentation and numerical techniques computer models of ventricular electrophysiology account for increasingly finer levels of anatomical and biophysical detail. However, considering the large number of model parameters involved parametrization poses a major challenge. A minimum requirement in co...

Fibrosis is thought to play an important role in formation and maintenance of atrial fibrillation (AF). The propensity of fibrosis to increase AF vulnerability depends not only on its amount, its texture plays a crucial role as well. While the detection of fibrotic tissue patches in the atria with extracellular recordings is feasible based on the a...

In this work, edge sets are mapped one to the other by representing these zero area sets as diffuse images which have positive measure supports that can be registered elastically. The driving application for this work is to map a Purkinje fiber network in the endocardium of one heart to the endocardium of another heart. The approach is to register...

Thin-walled cardiac tissue samples superfused with oxygenated solutions are widely used in experimental studies. However, due to decreased oxygen supply and insufficient wash out of waste products in the inner layers of such preparations, electrophysiological functions could be compromised. Although the cascade of events triggered by cutting off pe...

The presence of connective tissue as well as interstitial clefts forms a natural barrier to the electrical propagation in the heart. At a microscopic scale, such uncoupling structures change the pattern of the electrical conduction from uniform towards complex and may play a role in the genesis of cardiac arrhythmias. The anatomical diversity of co...

Electrical activity in cardiac tissue can be described by the bidomain equations whose solution for large-scale simulations still remains a computational challenge. Therefore, improvements in the discrete formulation of the problem, which decrease computational and/or memory demands are highly desirable. In this study, we propose a novel technique...

In this work, edge sets are mapped one to the other by representing these zero area sets as diffuse images which have positive measure supports that can be registered elastically. The driving application for this work is to map a Purkinje fiber network in the epicardium of one heart to the epicardium of another heart. The approach is to register su...

In experiments with cardiac tissue, local conduction is described by waveform analysis of the derivative of the extracellular potential Φ(e) and by the loop morphology of the near-field strength E (the components of the electric field parallel and very close to the tissue surface). The question arises whether the features of these signals can be us...

Computational approaches to investigating the electromechanics of healthy and diseased hearts are becoming essential for the comprehensive understanding of cardiac function. In this article, we first present a brief review of existing image-based computational models of cardiac structure. We then provide a detailed explanation of a processing pipel...

This paper presents methods to build histo-anatomically detailed individualized cardiac models. The models are based on high-resolution three-dimensional anatomical and/or diffusion tensor magnetic resonance images, combined with serial histological sectioning data, and are used to investigate individualized cardiac function. The current state of t...