The conducted action potential. Models and comparison to experiments

Walton, M.K.; Fozzard, Harry A.

doi:10.1016/s0006-3495(83)84273-8

Cited by 44 publications

(23 citation statements)

References 13 publications

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“…Nevertheless, the precise relationship between VP and gNa remains unclear, with several authors proposing (15,45,46) and others disputing (47,48,56) (13,14), these affinities should still provide information useful in quantifying binding and comparing the effects of antiarrhythmic agents in a propagating system. This study is also potentially limited by the inability to control the APD in this propagating system.…”

Section: Discussionmentioning

confidence: 99%

Characterization of concentration- and use-dependent effects of quinidine from conduction delay and declining conduction velocity in canine Purkinje fibers.

et al. 1989

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The dynamic response of squared conduction velocity, 92, to repetitive stimulation in canine Purkinje fibers with quinidine was studied using a double-microelectrode technique. With stimulation, a frequency-dependent monoexponential increase in conduction delay (CD) and a decline in 92 were observed. The exponential rates and changes in steady-state CD and 92 were frequency-and concentration-dependent. The overall drug uptake rates describing blockade and the interpulse recovery interval were linearly related and steady-state values of 92 were linearly related to an exponential function of the stimulus intervals. Based on first-order binding, the frequency-and concentration-dependent properties of quinidine were characterized by the apparent binding and unbinding rates of 14.2±5.7 X 106 mol-' s-and 63±12 s-' for activated and 14.8±1.0 X 102 mol' . *s-and 0.16±0.03 so' for resting states. The recovery time constant extracted from the pulse train interpulse interval was 5.8±1.5 s compared with 5.1±0.6 s determined from a posttrain test pulse protocol. This study demonstrates that the kinetics ofdrug action can be derived from measures of impulse propagation. This provides a basis for characterizing frequency-dependent properties of antiarrhythmic agents in vivo and suggests the plausibility of a quantitative assessment of drug binding and recovery rates in man.

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Section: Discussionmentioning

confidence: 99%

Characterization of concentration- and use-dependent effects of quinidine from conduction delay and declining conduction velocity in canine Purkinje fibers.

et al. 1989

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“…Conduction velocity is determined by the active membrane properties of each cell (largely a function of I Na ) and tissue resistivity (electrical coupling among cells) [25]. Although we did not measure conduction velocity in this study, we did record maximum upstroke velocity, which reflects I Na .…”

Section: Aging-associated Changes In Atrial Electrophysiologymentioning

confidence: 96%

Age-associated changes in electrophysiologic remodeling: a potential contributor to initiation of atrial fibrillation

Anyukhovsky

Sosunov

Chandra

et al. 2005

Cardiovascular Research

126

108

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Objective: Although the incidence of atrial fibrillation (AF) increases with age, the cellular electrophysiological changes that render the atria of aged individuals more susceptible to AF remain poorly understood. We hypothesized that dispersion of atrial repolarization increases with aging, creating a substrate for initiation of AF. Methods: Four groups of dogs were studied: adult and old dogs in normal sinus rhythm (SR) and adult and old dogs with chronic AF (CAF) induced by rapid atrial pacing. In each dog, action potentials (AP) were recorded with microelectrodes from isolated endocardial preparations of four regions of right atrium and three regions of left atrium. Two indices of AP duration (APD) heterogeneity were obtained in each dog by calculating standard deviation (SD) and the coefficient of variation (COV=[SD/mean]Â100%). Results: In SR groups, APD averaged across all regions was significantly longer in old than in adult tissues. Both indices of APD heterogeneity were higher in old dogs in comparison to adult. At both ages, CAF was associated with significant APD shortening and a decrease in APD adaptation to rate. While CAF significantly increased both indices of APD heterogeneity in adult dogs, it significantly decreased them in old dogs. Conclusions: The increase of spatial variability in repolarization in old atria may contribute to the initiation of AF in the aged. CAF-induced APD shortening and a decrease in APD adaptation appear to be important for the maintenance of sustained AF in both adult and old atria. The CAF-induced increase in dispersion of repolarization may be important for AF stabilization in adults, while previously reported fibrosis and slowed conduction of premature beats may be important in the old for both AF initiation during SR and subsequent stabilization of AF.

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“…[26]. The diffusion coefficient determines the conduction velocity, which is proportional to the square root of bulk conductance [27,28]. A 1:2 ratio of conduction velocity therefore implies a 1:4 ratio of diffusion coefficient.…”

Section: Anisotropic Diffusionmentioning

confidence: 99%

Influence of cardiac tissue anisotropy on re-entrant activation in computational models of ventricular fibrillation

Clayton

2009

Physica D: Nonlinear Phenomena

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Published paper Clayton, R.H (2009) Influence of cardiac tissue anisotropy on re-entrant activation in computational models of ventricular fibrillation. Physica D-Nonlinear Phenomena, AbstractThe aim of this study was to establish the role played by anisotropic diffusion in (i) the number of filaments and epicardial phase singularities that sustain ventricular fibrillation in the heart, (ii) the lifetimes of filaments and phase singularities, and (iii) the creation and annihilation dynamics of filaments and phase singularities. A simplified monodomain model of cardiac tissue was used, with membrane excitation described by a simplified 3-variable model. The model was configured so that a single re-entrant wave was unstable, and fragmented into multiple re-entrant waves. Re-entry was then initiated in tissue slabs with varying anisotropy ratio. The main findings of this computational study are: (i) anisotropy ratio influenced the number of filaments sustaining simulated ventricular fibrillation, with more filaments present in simulations with smaller values of transverse diffusion coefficient, (ii) each re-entrant filament was associated with around 0.9 phase singularities on the surface of the slab geometry, (iii) phase singularities were longer lived than filaments, and (iv) the creation and annihilation of filaments and phase singularities were linear functions of the number of filaments and phase singularities, and these relationships were independent of the anisotropy ratio. This study underscores the important role played by tissue anisotropy in cardiac ventricular fibrillation.

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The conducted action potential. Models and comparison to experiments

Cited by 44 publications

References 13 publications

Characterization of concentration- and use-dependent effects of quinidine from conduction delay and declining conduction velocity in canine Purkinje fibers.

Characterization of concentration- and use-dependent effects of quinidine from conduction delay and declining conduction velocity in canine Purkinje fibers.

Age-associated changes in electrophysiologic remodeling: a potential contributor to initiation of atrial fibrillation

Influence of cardiac tissue anisotropy on re-entrant activation in computational models of ventricular fibrillation

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