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  1. Article ; Online: Summation of activation at the branch-stem transition of Mimosa pudica; a comparison with summation in cardiac tissue.

    de Bakker, Jacques M T / Coronel, Ruben

    PloS one

    2023  Volume 18, Issue 5, Page(s) e0286103

    Abstract: In Mimosa pudica plants, local and global responses to environmental stimuli are associated with different types of electrical activity. Non-damaging stimuli (e.g. cooling) generate action potentials (APs), whereas damaging stimuli (e.g. heating) are ... ...

    Abstract In Mimosa pudica plants, local and global responses to environmental stimuli are associated with different types of electrical activity. Non-damaging stimuli (e.g. cooling) generate action potentials (APs), whereas damaging stimuli (e.g. heating) are associated with variation potentials (VPs). Local cooling of Mimosa branches resulted in APs that propagated up to the branch-stem interface and caused drooping of the branch (local response). This electrical activation did not pass the interface. If the branch was triggered by heat, however, a VP was transferred to the stem and caused activation of the entire plant (global response). VPs caused by heat were always preceded by APs and summation of the two types of activation appeared to be necessary for the activation to pass the branch-stem interface. Mechanical cutting of leaves also resulted in VPs preceded by APs, but in those cases a time delay was present between the two activations, which prevented adequate summation and transmission of activation. Simultaneous cold-induced activation of a branch and the stem below the interface occasionally resulted in summation sufficient to activate the stem beyond the interface. To investigate the effect of activation delay on summation, a similar structure of excitable converging pathways, consisting of a star-shaped pattern of neonatal rat heart cells, was used. In this model, summation of activation was not hindered by a small degree of asynchrony. The observations indicate that summation occurs in excitable branching structures and suggest that summation of activation plays a role in the propagation of nocuous stimuli in Mimosa.
    MeSH term(s) Animals ; Rats ; Mimosa ; Plant Leaves/physiology ; Plants ; Electricity ; Action Potentials
    Language English
    Publishing date 2023-05-19
    Publishing country United States
    Document type Journal Article
    ZDB-ID 2267670-3
    ISSN 1932-6203 ; 1932-6203
    ISSN (online) 1932-6203
    ISSN 1932-6203
    DOI 10.1371/journal.pone.0286103
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: Do Myofibroblasts Represent a Hidden Factor for Impaired Conduction and Tachyarrhythmia in Post-Myocardial Infarction?

    de Bakker, Jacques M T

    JACC. Clinical electrophysiology

    2017  Volume 3, Issue 7, Page(s) 715–717

    MeSH term(s) Animals ; Heart ; Myocardial Infarction ; Myofibroblasts ; Swine ; Tachycardia, Ventricular
    Language English
    Publishing date 2017-04-26
    Publishing country United States
    Document type Editorial ; Comment
    ZDB-ID 2846739-5
    ISSN 2405-5018 ; 2405-500X ; 2405-500X
    ISSN (online) 2405-5018 ; 2405-500X
    ISSN 2405-500X
    DOI 10.1016/j.jacep.2017.01.007
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article ; Online: Excitability and propagation of the electrical impulse in Venus flytrap; a comparative electrophysiological study of unipolar electrograms with myocardial tissue.

    de Bakker, Jacques M T / Belterman, Charly N W / Coronel, Ruben

    Bioelectrochemistry (Amsterdam, Netherlands)

    2021  Volume 140, Page(s) 107810

    Abstract: Mammalian heart cells and cells of leaves of Dionaea muscipula share the ability to generate propagated action potentials, because the excitable cells are electrically coupled. In the heart the propagated action potential causes synchronized contraction ... ...

    Abstract Mammalian heart cells and cells of leaves of Dionaea muscipula share the ability to generate propagated action potentials, because the excitable cells are electrically coupled. In the heart the propagated action potential causes synchronized contraction of the heart muscle after automatic generation of the impulse in the sinus node. In Dionaea propagation results in closure of the trap after activation of trigger hairs by an insect. The electrical activity can be recorded in the extracellular space as an extracellular electrogram, resulting from transmembrane currents. Although the underlying physiological mechanism that causes the electrogram is similar for heart and Dionaea cells, the contribution of the various ions to the transmembrane current is different. We recorded extracellular electrograms from Dionaea leaves and compared the recorded signals with those known from the heart. The morphology of the electrograms differed considerably. In comparison to activation in mammalian myocardium, electrograms of Dionaea are more temporally and spatially variable. Whereas electrograms in healthy myocardium recorded at some distance from the site of activation reveal a simple biphasic pattern, Dionaea activation showed positive, negative or biphasic deflections. Comparison of patch clamp data from plant cells and cardiomyocytes suggests a role of temperature and ion concentrations in extracellular space for the diversity of morphologies of the Dionaea electrograms.
    MeSH term(s) Droseraceae/cytology ; Droseraceae/physiology ; Electrophysiological Phenomena ; Extracellular Space/metabolism ; Heart/physiology
    Language English
    Publishing date 2021-03-31
    Publishing country Netherlands
    Document type Comparative Study ; Journal Article
    ZDB-ID 2010650-6
    ISSN 1878-562X ; 0302-4598 ; 1567-5394
    ISSN (online) 1878-562X
    ISSN 0302-4598 ; 1567-5394
    DOI 10.1016/j.bioelechem.2021.107810
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  4. Article ; Online: Multielectrode Contact Measurement Can Improve Long-Term Outcome of Pulmonary Vein Isolation Using Circular Single-Pulse Electroporation Ablation.

    Groen, Marijn H A / van Driel, Vincent J H M / Neven, Kars / van Wessel, Harry / de Bakker, Jacques M T / Doevendans, Pieter A F / Wittkampf, Fred H M / Loh, Peter / van Es, René

    Circulation. Arrhythmia and electrophysiology

    2022  Volume 15, Issue 8, Page(s) e010835

    Abstract: Background: Irreversible electroporation (IRE) ablation is generally performed with multielectrode catheters. Electrode-tissue contact is an important predictor for the success of pulmonary vein (PV) isolation; however, contact force is difficult to ... ...

    Abstract Background: Irreversible electroporation (IRE) ablation is generally performed with multielectrode catheters. Electrode-tissue contact is an important predictor for the success of pulmonary vein (PV) isolation; however, contact force is difficult to measure with multielectrode ablation catheters. In a preclinical study, we assessed the feasibility of a multielectrode impedance system (MEIS) as a predictor of long-term success of PV isolation. In addition, we present the first-in-human clinical experience with MEIS.
    Methods: In 10 pigs, one PV was ablated based on impedance (MEIS group), and the other PV was solely based on local electrogram information (EP group). IRE ablations were performed at 200 J. After 3 months, recurrence of conduction was assessed. Subsequently, in 30 patients undergoing PV isolation with IRE, MEIS was evaluated and MEIS contact values were compared to local electrograms.
    Results: In the porcine study, 43 IRE applications were delivered in 19 PVs. Acutely, no reconnections were observed in either group. After 3 months, 0 versus 3 (
    Conclusions: Data from the animal study suggest that MEIS values predict effective IRE applications. For the long-term success of electrical PV isolation with circular IRE applications, no significant difference in efficacy was found between ablation based on the measurement of electrode interface impedance and ablation using the classical EP approach for determining electrode-tissue contact. Experiences of the first clinical use of MEIS were promising and serve as an important basis for future research.
    MeSH term(s) Animals ; Atrial Fibrillation/surgery ; Catheter Ablation/adverse effects ; Catheter Ablation/methods ; Electroporation ; Heart Rate ; Humans ; Pulmonary Veins/surgery ; Swine ; Treatment Outcome
    Language English
    Publishing date 2022-08-02
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2426129-4
    ISSN 1941-3084 ; 1941-3149
    ISSN (online) 1941-3084
    ISSN 1941-3149
    DOI 10.1161/CIRCEP.121.010835
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article: Quantitative Approach to Fragmented QRS in Arrhythmogenic Cardiomyopathy: From Disease towards Asymptomatic Carriers of Pathogenic Variants.

    Roudijk, Rob W / Bosman, Laurens P / van der Heijden, Jeroen F / de Bakker, Jacques M T / Hauer, Richard N W / van Tintelen, J Peter / Asselbergs, Folkert W / Te Riele, Anneline S J M / Loh, Peter

    Journal of clinical medicine

    2020  Volume 9, Issue 2

    Abstract: Fragmented QRS complexes (fQRS) are common in patients with arrhythmogenic cardiomyopathy (ACM). A new method of fQRS quantification may aid early disease detection in pathogenic variant carriers and assessment of prognosis in patients with early stage ... ...

    Abstract Fragmented QRS complexes (fQRS) are common in patients with arrhythmogenic cardiomyopathy (ACM). A new method of fQRS quantification may aid early disease detection in pathogenic variant carriers and assessment of prognosis in patients with early stage ACM. Patients with definite ACM (
    Language English
    Publishing date 2020-02-17
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2662592-1
    ISSN 2077-0383
    ISSN 2077-0383
    DOI 10.3390/jcm9020545
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article ; Online: Long-Standing Persistent Atrial Fibrillation: Can We Distinguish Ectopic Activity From Reentry by Epicardial Mapping?

    de Bakker, Jacques M T / van Dessel, Pascal F H M

    Circulation

    2015  Volume 132, Issue 22, Page(s) 2103–2105

    MeSH term(s) Atrial Fibrillation/diagnostic imaging ; Atrial Fibrillation/physiopathology ; Epicardial Mapping/instrumentation ; Epicardial Mapping/methods ; Female ; Humans ; Male ; Ultrasonography
    Language English
    Publishing date 2015-12-01
    Publishing country United States
    Document type Editorial ; Comment
    ZDB-ID 80099-5
    ISSN 1524-4539 ; 0009-7322 ; 0069-4193 ; 0065-8499
    ISSN (online) 1524-4539
    ISSN 0009-7322 ; 0069-4193 ; 0065-8499
    DOI 10.1161/CIRCULATIONAHA.115.019417
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  7. Article: Severe Bradycardia Increases the Incidence and Severity of Torsade de Pointes Arrhythmias by Augmenting Preexistent Spatial Dispersion of Repolarization in the CAVB Dog Model.

    van Weperen, Valerie Y H / Dunnink, Albert / Bossu, Alexandre / Beekman, Jet D M / Meijborg, Veronique M F / de Bakker, Jacques M T / Coronel, Ruben / Varkevisser, Rosanne / van der Heyden, Marcel A G / Vos, Marc A

    Frontiers in physiology

    2021  Volume 12, Page(s) 642083

    Abstract: Introduction: Torsade de pointes arrhythmias (TdP) in the chronic atrioventricular block (CAVB ...

    Abstract Introduction: Torsade de pointes arrhythmias (TdP) in the chronic atrioventricular block (CAVB) dog model result from proarrhythmic factors, which trigger TdP and/or reinforce the arrhythmic substrate. This study investigated electrophysiological and arrhythmogenic consequences of severe bradycardia for TdP.
    Methods: Dofetilide (25 μg/kg per 5 min) was administered to eight anesthetized, idioventricular rhythm (IVR) remodeled CAVB dogs in two serial experiments: once under 60 beats per minute (bpm), right ventricular apex paced (RVA60) conditions, once under more bradycardic IVR conditions. Recordings included surface electrocardiogram and short-term variability (STV) of repolarization from endocardial unipolar electrograms. TdP inducibility (three or more episodes within 10 min after start of dofetilide) and arrhythmic activity scores (AS) were established. Mapping experiments in 10 additional dogs determined the effect of lowering rate on STV and spatial dispersion of repolarization (SDR) in baseline.
    Results: IVR-tested animals had longer baseline RR-interval (1,403 ± 271 ms) and repolarization intervals than RVA60 animals. Dofetilide increased STV similarly under both rhythm strategies. Nevertheless, TdP inducibility and AS were higher under IVR conditions (6/8 and 37 ± 27 vs. 1/8 and 8 ± 12 in RVA60, respectively, both
    Conclusion: In CAVB dogs, severe bradycardia increases the probability and severity of arrhythmic events by heterogeneously causing electrophysiological instability, which is mainly reflected in an increased spatial, and to a lesser extent temporal, dispersion of repolarization.
    Language English
    Publishing date 2021-04-26
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2564217-0
    ISSN 1664-042X
    ISSN 1664-042X
    DOI 10.3389/fphys.2021.642083
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  8. Article: How to measure propagation velocity in cardiac tissue: a simulation study.

    Linnenbank, Andre C / de Bakker, Jacques M T / Coronel, Ruben

    Frontiers in physiology

    2014  Volume 5, Page(s) 267

    Abstract: To estimate conduction velocities from activation times in myocardial tissue, the "average vector" method computes all the local activation directions and velocities from local activation times and estimates the fastest and slowest propagation speed from ...

    Abstract To estimate conduction velocities from activation times in myocardial tissue, the "average vector" method computes all the local activation directions and velocities from local activation times and estimates the fastest and slowest propagation speed from these local values. The "single vector" method uses areas of apparent uniform elliptical spread of activation and chooses a single vector for the estimated longitudinal velocity and one for the transversal. A simulation study was performed to estimate the influence of grid size, anisotropy, and vector angle bin size. The results indicate that the "average vector" method can best be used if the grid- or bin-size is large, although systematic errors occur. The "single vector" method performs better, but requires human intervention for the definition of fiber direction. The average vector method can be automated.
    Language English
    Publishing date 2014-07-22
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2564217-0
    ISSN 1664-042X
    ISSN 1664-042X
    DOI 10.3389/fphys.2014.00267
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  9. Article ; Online: The pathophysiologic basis of fractionated and complex electrograms and the impact of recording techniques on their detection and interpretation.

    de Bakker, Jacques M T / Wittkampf, Fred H M

    Circulation. Arrhythmia and electrophysiology

    2010  Volume 3, Issue 2, Page(s) 204–213

    MeSH term(s) Arrhythmias, Cardiac/diagnosis ; Arrhythmias, Cardiac/physiopathology ; Artifacts ; Electrophysiologic Techniques, Cardiac ; Heart Conduction System/physiology ; Heart Diseases/diagnosis ; Heart Diseases/physiopathology ; Humans
    Language English
    Publishing date 2010-04
    Publishing country United States
    Document type Journal Article ; Review
    ZDB-ID 2426129-4
    ISSN 1941-3084 ; 1941-3149
    ISSN (online) 1941-3084
    ISSN 1941-3149
    DOI 10.1161/CIRCEP.109.904763
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  10. Article ; Online: Cardiomyocyte Progenitor Cells as a Functional Gene Delivery Vehicle for Long-Term Biological Pacing.

    Végh, Anna M D / den Haan, A Dénise / Cócera Ortega, Lucía / Verkerk, Arie O / Sluijter, Joost P G / Bakker, Diane / van Amersfoorth, Shirley / van Veen, Toon A B / Klerk, Mischa / Seppen, Jurgen / de Bakker, Jacques M T / Christoffels, Vincent M / Geerts, Dirk / Goumans, Marie José T H / Tan, Hanno L / Boink, Gerard J J

    Molecules (Basel, Switzerland)

    2019  Volume 24, Issue 1

    Abstract: Sustained pacemaker function is a challenge in biological pacemaker engineering. Human cardiomyocyte progenitor cells (CMPCs) have exhibited extended survival in the heart after transplantation. We studied whether lentivirally transduced CMPCs that ... ...

    Abstract Sustained pacemaker function is a challenge in biological pacemaker engineering. Human cardiomyocyte progenitor cells (CMPCs) have exhibited extended survival in the heart after transplantation. We studied whether lentivirally transduced CMPCs that express the pacemaker current
    MeSH term(s) Animals ; Gene Transfer Techniques ; Genetic Therapy/methods ; Green Fluorescent Proteins/chemistry ; Heart Ventricles/pathology ; Heart Ventricles/transplantation ; Humans ; Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels/genetics ; Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels/therapeutic use ; Muscle Proteins/genetics ; Muscle Proteins/therapeutic use ; Myocytes, Cardiac/transplantation ; Patch-Clamp Techniques ; Potassium Channels/genetics ; Potassium Channels/therapeutic use ; Rats ; Stem Cell Transplantation ; Stem Cells/cytology
    Chemical Substances HCN4 protein, human ; Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels ; Muscle Proteins ; Potassium Channels ; Green Fluorescent Proteins (147336-22-9)
    Language English
    Publishing date 2019-01-05
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 1413402-0
    ISSN 1420-3049 ; 1431-5165 ; 1420-3049
    ISSN (online) 1420-3049
    ISSN 1431-5165 ; 1420-3049
    DOI 10.3390/molecules24010181
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