Mechanisms of vortices termination in the cardiac muscle

Hornung, Daniel; Biktashev, V. N.; Otani, Niels F.; Shajahan, T. K.; Baig, Tariq; Berg, Sebastian; Han, S.; Krinsky, V. I.

doi:10.1098/rsos.170024

Cited by 25 publications

(23 citation statements)

References 34 publications

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“…In these papers, it was demonstrated that vortices that were assumed to be pinned at larger heterogeneities in cardiac tissue are best terminated if the pacing frequency in a LEAP procedure is set to be 80 -90% of the dominant frequency (the rotation frequency of the vortex around the pinning site). Such a choice of pacing frequency allows for an efficient scanning of the phase of the vortex in order to find the vulnerable window for vortex termination 27,28 . A simulation study in a realistic three-dimensional cardiac geometry demonstrated for selected examples that LEAP works for a pacing period of 88% of the VF cycle length, but often fails for much faster pacing with a period of 16% of the VF cycle length 29 .…”

Section: Introductionmentioning

confidence: 99%

Control of electrical turbulence by periodic excitation of cardiac tissue

Buran

Bär

Alonso

et al. 2017

Chaos: An Interdisciplinary Journal of Nonlinear Science

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Electrical turbulence in cardiac tissue is associated with arrhythmias such as the life-threatening ventricular fibrillation. The application of a high-energy electrical shock constitutes an effective defibrillation, but also causes severe side effects. Recent experimental studies have shown that a sequence of low energy electrical far-field pulses is able to terminate fibrillation more gently than a single pulse. During this low-energy antifibrillation pacing (LEAP) only tissue near sufficiently large conduction heterogeneities, such as large coronary arteries, is activated. In order to understand and potentially optimize LEAP, we performed extensive simulations of cardiac tissue perforated by blood vessels. We checked three alternative cellular models that exhibit qualitatively different electrical turbulence. LEAP may operate if and only if the spectrum of this chaotic activity is characterized by a narrow peak around a dominant frequency. For each of 100 initial conditions, we tested different electrical field strengths, pulse shapes, numbers of pulses, and periods between the pulses. It turned out that the optimal period matches the dominant period of the chaotic activity while both over-and underdrive pacing lead to a considerably smaller success probability and higher field strength for reliable defibrillation. An optimal LEAP protocol, which minimizes the required total energy for successful defibrillation, consists of five or six pulses. Compared to a single bi-phasic defibrillation pulse, it reduces the total energy by about 86%, corresponding to an energy reduction of 97 -98% per pulse.PACS numbers: ... Keywords: cardiac modeling, excitable media, defibrillation, low-energy antifibrillation pacing (LEAP)In ventricular fibrillation, the heart is quivering instead of pumping, a condition which leads to cardiac arrest and ultimately to death. This loss of synchronous contraction stems from disorganized electrical activity in the ventricles. Emergency defibrillation is achieved by the application of a strong electrical shock which is accompanied by severe side effects such as tissue damage and trauma. Recently, an alternative treatment using a sequence of low energy pulses has been suggested in which each electrical pulse excites only localized tissue sites at the large heterogeneities -such as blood vessels -instead of the entire tissue. In laboratory experiments in vitro and in vivo, this so-called low-energy antifibrillation pacing (LEAP) with five pulses achieves defibrillation with an energy reduction of 80 -90 % per pulse in comparison with standard single shock treatment. Here, we perform an extensive numerical study of LEAP employing far field pacing at the major blood vessels. We have tested three alternative electrophysiological models that exhibit qualitatively different spatiotemporally chaotic activity. LEAP operates if and only if the spectrum of this chaotic activity is characterized by a narrow peak around a dominant frequency. In this case, a resonant pacing with the same frequency and a ...

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Section: Introductionmentioning

confidence: 99%

Control of electrical turbulence by periodic excitation of cardiac tissue

Buran

Bär

Alonso

et al. 2017

Chaos: An Interdisciplinary Journal of Nonlinear Science

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“…The mechanism of arrhythmia termination was confirmed by optical mapping [13]. A deep understanding of how pinned 2-dimensional vortices can be terminated currently exists [10].…”

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confidence: 87%

“…These two waves annihilate and disappear, see e.g., Fig. 4d in [10]. This type of wave behavior is not possible in classical mechanics with the energy conservation law.…”

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confidence: 96%

Termination of Scroll Waves by Surface Impacts

2019

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Three-dimensional scroll waves direct cell movement and gene expression, and induce chaos in the brain and heart. We found an approach to terminate multiple 3 dimensional scrolls. A pulse of a properly configured electric field detaches scroll filaments from the surface. They shrink due to filament tension and disappear. Since wave emission from small heterogeneities is not used, this approach requires a much lower electric field. It is not sensitive to the details of the excitable medium. It may affect future studies of low-energy chaos termination in the heart. 565 characters with spaces.

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“…In 2D, the interaction of the waves launched by the electric field with the rotating waves depends on the location of the rotating waves and where the waves are in their rotation when the electric field pulse is applied [6,7]. In contrast, in 3D, if a significant component of the electric field pulse is oriented along the axis of rotation of the rotating wave, then the result is, at some fundamental level, independent of where the wave is in its rotation [8,9].…”

Section: Motivation and Methodsmentioning

confidence: 99%

A New, Low-Energy Defibrillation Strategy: Use of Multiple Electric Field Directions to Reshape Scroll Wave Filaments

Wheeler

Krinski

Otani

2017

Computing in Cardiology Conference (CinC)

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There is continued interest in developing new, lowenergy methods for cardiac defibrillation. In this computational study, we consider the problem from a new perspective that, in contrast to several previous studies, leads to a strategy that works even when an arbitrarily large number of the rotating action potential waves are present during fibrillation, and works without requiring knowledge of the phases of these rotating waves. We show that sequences of one or more low-energy, electric field pulses, when designed with this strategy in mind, can convert the axes around which the waves rotate from a persistent form into forms that tend to shrink and disappear. When these sequences were applied with field strengths between 1.5 and 2.5 V/cm, 1 to 4 rotating waves representing fibrillation were terminated with success rates (76%-90%) much higher than those obtained using conventional stimuli (14%). Limitations of this study include our use of a simplified model of cardiac geometry and our operation of the simulation in a positive filament tension regime that is also stable to electrical alternans. Nevertheless, we believe that the use of a sequence of electric fields designed to convert all persistent filament shapes to self-extinguishing ones is a promising idea that is worth further examination.

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Mechanisms of vortices termination in the cardiac muscle

Cited by 25 publications

References 34 publications

Control of electrical turbulence by periodic excitation of cardiac tissue

Control of electrical turbulence by periodic excitation of cardiac tissue

Termination of Scroll Waves by Surface Impacts

A New, Low-Energy Defibrillation Strategy: Use of Multiple Electric Field Directions to Reshape Scroll Wave Filaments

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