An Experimental Study of Propagated Electrical Activity in the Canine Heart

Ark, Condon R. Vander; Reynolds, Ernest W.

doi:10.1161/01.res.26.4.451

Cited by 36 publications

(13 citation statements)

References 5 publications

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“…With 750-m separation, an additional feature of the bipolar electrogram was a prolongation of the time over which the electrogram remained at peak potential. This characteristic is consistent with the positioning of recording electrodes outside the width of the electromotive surface of the depolarization wavefront (31), and its presence was associated with marked deviations in estimated I m identified by Witkowski et al (32). Figure 4A, right, shows bipolar electrograms recorded with electrode separations of 12.5, 25.0, and 37.5 m, which were finer separations than we achieved with microfabrication.…”

Section: Unipolar Electrogram Recordingssupporting

confidence: 87%

Measuring surface potential components necessary for transmembrane current computation using microfabricated arrays

Wiley¹,

Ideker²,

Smith³

et al. 2005

American Journal of Physiology-Heart and Circulatory Physiology

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This study was designed to test the feasibility of using microfabricated electrodes to record surface potentials with sufficiently fine spatial resolution to measure the potential gradients necessary for improved computation of transmembrane current density. To assess that feasibility, we recorded unipolar electrograms from perfused rabbit right ventricular free wall epicardium (n = 6) using electrode arrays that included 25-microm sensors fabricated onto a flexible substrate with 75-microm interelectrode spacing. Electrode spacing was therefore on the size scale of an individual myocyte. Signal conditioning adjacent to the sensors to control lead noise was achieved by routing traces from the electrodes to the back side of the substrate where buffer amplifiers were located. For comparison, recordings were also made using arrays built from chloridized silver wire electrodes of either 50-microm (fine wire) or 250-microm (coarse wire) diameters. Electrode separations were necessarily wider than with microfabricated arrays. Comparable signal-to-noise ratios (SNRs) of 21.2 +/- 2.2, 32.5 +/- 4.1, and 22.9 +/- 0.7 for electrograms recorded using microfabricated sensors (n = 78), fine wires (n = 78), and coarse wires (n = 78), respectively, were found. High SNRs were maintained in bipolar electrograms assembled using spatial combinations of the unipolar electrograms necessary for the potential gradient measurements and in second-difference electrograms assembled using spatial combinations of the bipolar electrograms necessary for surface Laplacian (SL) measurements. Simulations incorporating a bidomain representation of tissue structure and a two-dimensional network of guinea pig myocytes prescribed following the Luo and Rudy dynamic membrane equations were completed using 12.5-microm spatial resolution to assess contributions of electrode spacing to the potential gradient and SL measurements. In those simulations, increases in electrode separation from 12.5 to 75.0, 237.5, and 875.0 microm, which were separations comparable to the finest available with our microfabricated, fine wire, and coarse wire arrays, led to 10%, 42%, and 81% reductions in maximum potential gradients and 33%, 76%, and 96% reductions in peak-to-peak SLs. Maintenance of comparable SNRs for source electrograms was therefore important because microfabrication provides a highly attractive methods to achieve spatial resolutions necessary for improved computation of transmembrane current density.

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Section: Unipolar Electrogram Recordingssupporting

confidence: 87%

Measuring surface potential components necessary for transmembrane current computation using microfabricated arrays

Wiley¹,

Ideker²,

Smith³

et al. 2005

American Journal of Physiology-Heart and Circulatory Physiology

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“…Vander Ark and Reynolds (1970) reported a voltage of 74.1 ± 8.3 mV across depolarization waves on the ventricular epicardium. This presumably corresponds to our longitudinal wavefront voltage, V o i = 74 ± 7 mV.…”

Section: Discussionmentioning

confidence: 99%

Effect of tissue anisotropy on extracellular potential fields in canine myocardium in situ.

Roberts¹,

Scher²

1982

Circulation Research

238

159

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SUMMARY. The extracellular epicardial potential fields produced by simple depolarization waves in the in situ canine left ventricular myocardium were analyzed. A mathematical model that included tissue anisotropy was developed to explain the observed fields. Values of intracellular (i), extracellular (o), longitudinal (f), and transverse (t) resistivity which gave the best fit between the model and experimental data were (in ohm-cm, mean ± SD): r,,, = 852 ± 232, r,,, = 1247 ± 210, r,, = 291 ± 38, rii = 1677 ± 331. The potential fields around simple stimulated waves on the epicardium can best be explained if the extracellular wavefront voltage is (mean ± SD) 74 ± 7 mV for a wave propagating parallel to the local muscle fibers, and 43 ± 6 mV for a wave propagating perpendicular to these fibers. We conclude that the anisotropy of the electrical conductivity of cardiac muscle has important effects on the propagation of waves of depolarization and on the potential fields produced by depolarization in the intact heart. (Circ Res 50: 342-351, 1982)

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“…finite element modeling) but require high spatial resolution. In contrast, the multi-electrode catheters used clinically to detect rotors have limited spatial resolution with an inter-electrode distance (IED) of 9–11 mm, which is considerably larger than the wavefront width (1–3 mm) [29,30]. Therefore, the representation of equiphase lines in phase mapping requires extensive interpolation to cover the large unexplored areas.…”

Section: Introductionmentioning

confidence: 99%

Impact of number of co-existing rotors and inter-electrode distance on accuracy of rotor localization

Aronis

Ashikaga

2018

Journal of Electrocardiology

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Background Conflicting evidence exists on the efficacy of focal impulse and rotor modulation on atrial fibrillation ablation. A potential explanation is inaccurate rotor localization from multiple rotors coexistence and a relatively large (9–11 mm) inter-electrode distance (IED) of the multi-electrode basket catheter. Methods and results We studied a numerical model of cardiac action potential to reproduce one through seven rotors in a two-dimensional lattice. We estimated rotor location using phase singularity, Shannon entropy and dominant frequency. We then spatially downsampled the time series to create IEDs of 2–30 mm. The error of rotor localization was measured with reference to the dynamics of phase singularity at the original spatial resolution (IED = 1 mm). IED has a significant impact on the error using all the methods. When only one rotor is present, the error increases exponentially as a function of IED. At the clinical IED of 10 mm, the error is 3.8 mm (phase singularity), 3.7 mm (dominant frequency), and 11.8 mm (Shannon entropy). When there are more than one rotors, the error of rotor localization increases 10-fold. The error based on the phase singularity method at the clinical IED of 10 mm ranges from 30.0 mm (two rotors) to 96.1 mm (five rotors). Conclusions The magnitude of error of rotor localization using a clinically available basket catheter, in the presence of multiple rotors might be high enough to impact the accuracy of targeting during AF ablation. Improvement of catheter design and development of high-density mapping catheters may improve clinical outcomes of FIRM-guided AF ablation.

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An Experimental Study of Propagated Electrical Activity in the Canine Heart

Cited by 36 publications

References 5 publications

Measuring surface potential components necessary for transmembrane current computation using microfabricated arrays

Measuring surface potential components necessary for transmembrane current computation using microfabricated arrays

Effect of tissue anisotropy on extracellular potential fields in canine myocardium in situ.

Impact of number of co-existing rotors and inter-electrode distance on accuracy of rotor localization

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