What is the clinical evidence from this study?

Study design: Other. Intervention: Source separation variation. Primary outcome: Chronaxie and rheobase values of the strength-duration relation.

What question did this study set out to answer?

This research aims to understand how the separation between virtual electrode sources affects cardiac tissue response to electric stimulation.

May 1, 1999Journal of Cardiovascular Electrophysiology

Separation Between Virtual Sources Modifies the Response of Cardiac Tissue to Field Stimulation

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Key result

Tissue excitation in response to field stimulation is strongly modulated by the proximity of oppositely polarized virtual electrode sources, with chronaxie decreasing under 0.2 mm separation.

Population

Homogeneous tissue strip model (active membrane dynamics modeled with the Luo-Rudy phase I formulation)

Comparison

Uniform extracellular field stimulation with… vs Different source separations

Design

Preclinical

Authors

RSRobert C. SusilJohns Hopkins Hospital EAEric AssénatCentre National de la Recherche Scientifique LTLeslie TungElectrophysiology

Discussion

Member takes

Implication

Virtual electrode proximity effects in animal tissue warrant no clinical change; hypothesis-generating for field stimulation mechanisms in humans.

Key Points

This research aims to understand how the separation between virtual electrode sources affects cardiac tissue response to electric stimulation.
Model system uses a homogeneous tissue strip stimulated by a uniform extracellular field.
Chronaxie and rheobase values were determined for source separations ranging from 1.0 cm to 100 microm.
The Luo-Rudy phase I formulation was used to model active membrane dynamics.
At separations greater than 3.0 mm, the chronaxie remained constant at 3.09 msec and rheobase was 0.38 V/cm.
At separations under 0.2 mm, chronaxie decreased to 0.55 msec and rheobase increased with the inverse of source separation.
Effects of source interaction are primarily due to passive electrotonic interactions, influenced by active tissue properties.

Structured PICO

Population

Homogeneous tissue strip model (active membrane dynamics modeled with the Luo-Rudy phase I formulation)

Intervention

Uniform extracellular field stimulation with varying source separations (1.0 cm to 100 microm)

Comparator

Different source separations

Outcome

Chronaxie and rheobase values of the strength-duration relationsurrogate

Tissue excitation in response to field stimulation is strongly modulated by the proximity of, and interaction between, oppositely polarized virtual electrode sources.

Cite This Study

Susil et al. (1999) studied this question. Source separation variation was evaluated on Chronaxie and rheobase values of the strength-duration relation. Tissue excitation in response to field stimulation is strongly modulated by the proximity of oppositely polarized virtual electrode sources, with chronaxie decreasing under 0.2 mm separation.

synapsesocial.com/papers/6a6c210847a1bfb288f36ae7 https://doi.org/10.1111/j.1540-8167.1999.tb00248.x

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Implication

Virtual electrode proximity effects in animal tissue warrant no clinical change; hypothesis-generating for field stimulation mechanisms in humans.

Separation Between Virtual Sources Modifies the Response of Cardiac Tissue to Field Stimulation

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Separation Between Virtual Sources Modifies the Response of Cardiac Tissue to Field Stimulation

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Also Consider

Also Consider