Entropy Rate Maps of Complex Excitable Dynamics in Cardiac Monolayers

Schlemmer, Alexander; Berg, Sebastian; Shajahan, T. K.; Parlitz, Ulrich

doi:10.3390/e17030950

Cited by 7 publications

(4 citation statements)

References 19 publications

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“…Ventricular myocytes from eight-day old chicken embryos were cultured as described in [32,33]. These cells were then plated on a cover glass as a circular disk of diameter 1 cm and at a density of 36 000 cells per square centimeter.…”

Section: Methodsmentioning

confidence: 99%

Scanning and resetting the phase of a pinned spiral wave using periodic far field pulses

et al. 2016

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Spiral waves in cardiac tissue can pin to tissue heterogeneities and form stable pinned waves. These waves can be unpinned by electric stimuli applied close to the pinning center during the vulnerable window of the spiral. Using a phase transition curve (PTC), we quantify the response of a pinned wave in a cardiac monolayer to secondary excitations generated electric field pulses. The PTC can be used to construct a one-dimensional map that faithfully predicts the pinned wave's response to periodic field stimuli. Based on this 1D map, we predict that pacing at a frequency greater than the spiral frequency, over drive pacing, leads to phase locking of the spiral to the stimulus, which hinders unpinning. In contrast, under drive pacing can lead to scanning of the phase window of the spiral, which facilitates unpinning. The predicted mechanisms of phase scanning and phase locking are experimentally tested and confirmed in the same monolayers that were used to obtain the PTC. Our results have the potential to help choose optimal parameters for low energy antifibrillation pacing schemes.

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Section: Methodsmentioning

confidence: 99%

Scanning and resetting the phase of a pinned spiral wave using periodic far field pulses

et al. 2016

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“…The experiments were conducted in a monolayer of cardiac myocytes extracted from chicken embryos, prepared as described in [19,20] and plated as circular disks of 10 mm diameter. A hole with 2 mm diameter was drilled in the middle of the glass plate, creating a central heterogeneity without any cells.…”

Section: Methods (A) Experimentsmentioning

confidence: 99%

Spiral wave unpinning facilitated by wave emitting sites in cardiac monolayers

et al. 2019

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Rotating spiral waves of electrical activity in the heart can anchor to unexcitable tissue (an obstacle) and become stable pinned waves. A pinned rotating wave can be unpinned either by a local electrical stimulus applied close to the spiral core, or by an electric field pulse that excites the core of a pinned wave independently of its localization. The wave will be unpinned only when the pulse is delivered inside a narrow time interval called the unpinning window (UW) of the spiral. In experiments with cardiac monolayers, we found that other obstacles situated near the pinning centre of the spiral can facilitate unpinning. In numerical simulations, we found increasing or decreasing of the UW depending on the location, orientation and distance between the pinning centre and an obstacle. Our study indicates that multiple obstacles could contribute to unpinning in experiments with intact hearts.

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“…To reduce the noise, it is necessary to apply spatial filtering. The two main methods commonly employed in the cardiac sciences are either a square averaging or Gaussian kernel smoothing [81][82][83]. In this work, Gaussian kernels are used throughout for spatial smoothing.…”

Section: Spatial Smoothingmentioning

confidence: 99%

Characterization and Control of Wave Propagation in the Heart

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ACF Autocorrelation functionATP Adenosine diphosphate APD Action potential duration. APD 𝑋 at level 𝑋. ATP Adenosine triphosphate. In cardiology also used for anti tachycardia pacing. CLCycle length, the time between two events. Typically the cell excitation but also electric shocks/pacing. Δ Triangularity index, see 4.3.4. ECG Electrocardiogram LV Left ventricle, the left main chamber of the heart NPS Number of Phase Singularities ⟨NPS⟩ average Number of Phase Singularities within one Episode or analyzed Video. 𝒩 Number of Phase Singularities -used in quoted/included paper. PS Phase Singularity RV Right ventricle, the right main chamber of the heart VF Ventricular fibrillation -Arrhythmia associated with many spiral waves and chaotic dynamics.VT Ventricular tachycardia -Arrhythmia associated with a fast rhythm and few stable spiral waves. Glossary and Abbreviationsvii Glossary apex The lower tip of the heart.charge The toplogical charge of a PS. Thus the direction, left or right, the spiral wave rotates around the PS. Can be +1 or −1 (higher orders possible theoretically).chirality The direction of spiral wave rotation. For a PS synonymous with its charge.core The spiral core is the area around which the spiral rotates. Used synonymous with the PS.endocard The innermost layer of the heart, generally used to refer to dynamics close to the inside of the heart.epicard The outer protective layer, generally used to mean close to the outside of the heart. excitable gapThe time within the activation cycle of a cardiac cell during which it can be excited by an external stimulus.mother rotor A dominating rotor driving the fibrillation, as opposed fibrillation being driven by multiple wavelets.pacing A periodic electrical stimulus or shock, usually using a local electrode.Pinacidil A drug that opens ATP-sensitive potassium channels.reentry Any spiral wave like behaviour. A reentry can be a wave travelling on a ring like structure or a free spiral wave with a PS at its core. refractory timeThe time within the activation cycle of a cardiac cell during which an external stimulus cannot cause excitation.rotor Any spiral wave like behaviour.shock An electrical far field shock delivered through plate electrodes.trace The temporal signal from a single camera pixel or an averaged area.upstroke The initial phase during cardiac excitation of increasing action potential.vulnerable window The subset of the excitable gap, during which the newly created wave will be blocked in one direction and thus may create new spirals.wavebreak The point at which wavefront and waveback meet. Used as a synonym for a PS with a specific phase definition.wave emitting site Any place, typically a heterogeneity, where an electrical shock excites the tissue.Chapter 1• Finally, the last result chapter discusses how electric shocks interact with fibrillation. This discussion is mainly based on exemplary studies.At the end a summary and discussion of the results, and an outlook are given.

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Entropy Rate Maps of Complex Excitable Dynamics in Cardiac Monolayers

Cited by 7 publications

References 19 publications

Scanning and resetting the phase of a pinned spiral wave using periodic far field pulses

Scanning and resetting the phase of a pinned spiral wave using periodic far field pulses

Spiral wave unpinning facilitated by wave emitting sites in cardiac monolayers

Characterization and Control of Wave Propagation in the Heart

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