599 research outputs found
The Influence of Using a Static Diastolic Geometry in ECG Imaging
Get PDFOne of the common choices when performing electrocardiographic imaging (ECGI) is that the cardiac geometry is in a static, diastolic state. To test the influence of this approximation, we compared epicardial potential maps and isochrones during systolic and diastolic geometries in four patients. Zero-th order Tikhonov regularization was used to reconstruct ventricular epicardial potentials. A spatiotemporal estimation method was then used to determine the activation and recovery times from the reconstructed epicardial electrograms. Activation times (AT), recovery times (RT) and electrogram correlation coefficients (CC) were compared for both geometries. Furthermore, CC and differences in AT/ RT were correlated against the linear movement and a substitute for rotational movement. Poor correlation was found between linear/rotational movement and reconstruction differences. Overall, agreement between epicardial potential maps and isochrones of both geometries was high when assessed quantitatively, but regional differences might occur for qualitative interpretation. These differences mostly occurred in areas of flat T-waves. This novel, more accurate quantification of the influence of assuming a diastolic geometry in ECGI may further help in interpreting ECGI measurements.</p
Noninvasive assessment of dynamic cardiac electrophysiology in normal human subjects
No full textIntroduction
Electrocardiographic imaging (ECGI) has been used to investigate arrhythmia mechanisms in various conditions. Data on normal human subjects, especially in Europe, are scarce. Dynamic characteristics of ventricular activation and recovery during sinus rhythm have not been assessed before.
Purpose
To examine cardiac electrophysiology and its dynamic aspects in normal subjects using ECGI, in order to provide a range of normal patterns and values for activation (AT) and recovery times (RT), activation-recovery intervals (ARI, a surrogate for action potential duration) and their dynamicity.
Methods
11 Subjects (age 57±7 years, 27% male, all normal LVEF) with atypical chest pain who underwent a cardiac CT-scan as part of clinical care but who were negative for any pathology on full examination were included. A validated non-commercial potential-based formulation of ECGI was used to reconstruct unipolar electrograms (EGMs) on the epicardial surface for three sinus beats within minutes from each other, per individual. ATs and RTs were determined as the maximum negative upslope during QRS, and maximum positive upslope during T wave of the local EGMs. Additionally, we determined locations of first and last activation and recovery. Inter- and intra-individual differences were computed.
Results
Subjects had normal 12-lead characteristics without ST-deviations, and an average QTc interval of 415±18ms. Panel A shows ECGI during sinus rhythm for 3 representative subjects, and panel B summarizes all findings on the entire epicardium. The first epicardial activation breakthrough typically occurred on the right ventricle (RV), consistent with the concept that the thinner RV wall accounts for a faster transmural activation. Last activation was mostly on the base of the left ventricle (LV), on the inferior to lateral wall. Earliest recovery occurred predominantly on the anterior surface, while latest recovery occurred on the inferior surface. Complete activation of the epicardial surface (from earliest to latest AT) took 41±8ms, while recovery (earliest AT to latest RT) took 317±24ms and average ARI (local AT to local RT) took 232±23ms. Thus, inter-individual variation of recovery duration was higher than of activation. Intra-individual differences between beats in ATs, RTs and ARIs of distinct sinus beats were small (2.3±3.1ms, 9.7±8.8ms and 9.8±9.1ms, respectively) suggesting that ECGI enables stable reconstruction quality (panel C).
Conclusion
In this cohort, noninvasive ECGI provides novel insights in ventricular electrophysiology. Electrical recovery is more variable than activation, both intra-individually and inter-individually. Overall, AT, RT and ARI differences between sinus beats were low. ECGI appears suitable to assess dynamic electrical patterns during cardiac pathology
Noninvasive assessment of dynamic cardiac electrophysiology in normal human subjects
No full textIntroduction
Electrocardiographic imaging (ECGI) has been used to investigate arrhythmia mechanisms in various conditions. Data on normal human subjects, especially in Europe, are scarce. Dynamic characteristics of ventricular activation and recovery during sinus rhythm have not been assessed before.
Purpose
To examine cardiac electrophysiology and its dynamic aspects in normal subjects using ECGI, in order to provide a range of normal patterns and values for activation (AT) and recovery times (RT), activation-recovery intervals (ARI, a surrogate for action potential duration) and their dynamicity.
Methods
11 Subjects (age 57±7 years, 27% male, all normal LVEF) with atypical chest pain who underwent a cardiac CT-scan as part of clinical care but who were negative for any pathology on full examination were included. A validated non-commercial potential-based formulation of ECGI was used to reconstruct unipolar electrograms (EGMs) on the epicardial surface for three sinus beats within minutes from each other, per individual. ATs and RTs were determined as the maximum negative upslope during QRS, and maximum positive upslope during T wave of the local EGMs. Additionally, we determined locations of first and last activation and recovery. Inter- and intra-individual differences were computed.
Results
Subjects had normal 12-lead characteristics without ST-deviations, and an average QTc interval of 415±18ms. Panel A shows ECGI during sinus rhythm for 3 representative subjects, and panel B summarizes all findings on the entire epicardium. The first epicardial activation breakthrough typically occurred on the right ventricle (RV), consistent with the concept that the thinner RV wall accounts for a faster transmural activation. Last activation was mostly on the base of the left ventricle (LV), on the inferior to lateral wall. Earliest recovery occurred predominantly on the anterior surface, while latest recovery occurred on the inferior surface. Complete activation of the epicardial surface (from earliest to latest AT) took 41±8ms, while recovery (earliest AT to latest RT) took 317±24ms and average ARI (local AT to local RT) took 232±23ms. Thus, inter-individual variation of recovery duration was higher than of activation. Intra-individual differences between beats in ATs, RTs and ARIs of distinct sinus beats were small (2.3±3.1ms, 9.7±8.8ms and 9.8±9.1ms, respectively) suggesting that ECGI enables stable reconstruction quality (panel C).
Conclusion
In this cohort, noninvasive ECGI provides novel insights in ventricular electrophysiology. Electrical recovery is more variable than activation, both intra-individually and inter-individually. Overall, AT, RT and ARI differences between sinus beats were low. ECGI appears suitable to assess dynamic electrical patterns during cardiac pathology
Societal need for multifunctional flood defenses: Introduction
No full textProf.dr.ir. Matthijs Kok is Professor of Flood Risk at the Faculty of Civil Engineering and Geosciences at TU Delft; he was Program leader of the ‘Integral and Sustainable Design of Multifunctional Flood Defenses’ research program, funded by the Dutch Science and Technology Foundation STW. Presently, he is Program leader of the STW-Perspectief research program ‘All RISK’, which will study the implementation of new risk standards in the Dutch national flood protection program (2017-2022). Hydraulic Structures and Flood Ris
Arrhythmogenic vulnerability of reentrant pathways in post-infarct ventricular tachycardia assessed by advanced computational modelling
Get PDFThe Centro Nacional de Investigaciones Cardiovasculares (CNIC) is supported by the Ministry of Science and Innovation (MCIN) and the Pro
CNIC Foundation and is a Severo Ochoa Center of Excellence
(CEX2020-001041-S).S
Correction to: CT angiography vs echocardiography for detection of cardiac thrombi in ischemic stroke: a systematic review and meta-analysis (Journal of Neurology, (2020), 267, 6, (1793-1801), 10.1007/s00415-020-09766-8)
No full textThe original version of this article unfortunately contained a mistake. In the author list, the first and last names of two authors, S. Matthijs Boekholdt and R. Nils Planken, were tagged incorrectly. Therefore, author names are abbreviated wrongly in Springerlink. The first and last names should be as follows: First name: S. Matthijs Last name: Boekholdt First name: R. Nils Last name: Planken
An Open-Source Algorithm for Standardized Bullseye Visualization of High-Resolution Cardiac Ventricular Data: UNISYS
Get PDFStandardized visualization of electro- or mechano-anatomical data allows easy inter- and intra-patient comparison. For this purpose, we developed the open-source and freely available UNISYS (Universal Ventricular Bullseye Visualization) software. A patient-specific mesh of the ventricular anatomy typically consists of a certain number of vertices and their associated values. Based on a limited amount of user inputs, the algorithm transforms these 3D single-layer coordinates to a circular 2D disk ('bullseye') through a number of translations and rotations, and interpolates them to achieve a continuous standardized visualization. The algorithm shows a high degree of bidirectionality and a robust spatial preservation of points of interest.</p
"What drives ability peer effects?" Replication Datasets
No full textData repository for replication datasets of "What drives ability peer effects?", Max Coveney and Matthijs Oosterveen, European Economic Review.The archived datasets contain all variables that were available to the researchers and allows for complete replication. Separate datasets are used for the different types of analyses (student level, student-course level, student-pair level). The student and group IDs are anonymized to prevent identification of individuals. Access to the data can be granted by submitting a research request to the corresponding author ([email protected]).The full paper can be found at: https://doi.org/10.1016/j.euroecorev.2021.103763</div
Dynamics of Ventricular Electrophysiology Are Unmasked Through Noninvasive Electrocardiographic Imaging
Get PDFDynamic variability of ventricular activation and recovery can be a physiological phenomenon, but is also known to increase susceptibility to arrhythmias. It has been extensively studied on the 12-lead electrocardiogram (ECG), but subtle (patho)physiological variations may be challenging to detect and localize due to the limited spatial resolution. Electrocardiographic imaging (ECGI) could be a useful noninvasive high-resolution mapping technique to investigate ventricular dynamics in more detail. Ventricular activation and recovery times (ATs and RTs) were examined using ECGI in 10 normal subjects. Zero-th order Tikhonov regularization was used in combination with a spatiotemporal estimation method to determine ATs and RTs. Dynamics were defined as standard deviations of ventricular ATs and RTs over three beats. Dynamics were higher for recovery than for activation during sinus rhythm, and significantly exaggerated after ventricular ectopy. Left ventricular areas were less dynamic than right ventricular areas. Since arrhythmias may arise due to an increase in ventricular dynamics in the diseased heart, these results provide an important basis for future research on ventricular dynamics and arrhythmias
Multimodal Image Integration to Better Explain Human Ventricular Tachyarrhythmias
No full textPhD Thesis Job StoksHet verschijnen van dit proefschrift werd mede mogelijk gemaakt door de
steun van de Nederlandse Hartstichting.
Het onderzoek dat aan dit proefschrift ten grondslag ligt is mogelijk
gemaakt door een subsidie van de Nederlandse Hartstichting (CVON2017-13
VIGILANCE)
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