What question did this study set out to answer?

To determine whether the apparent membrane capacity of cardiac Purkyně fibres varies with the frequency of electrical excitation signals.

February 1, 1971The Journal of PhysiologyOpen Access

The frequency dependent character of the membrane capacity in cardiac Purkyně fibres

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Population

Cardiac Purkinje fibers

Comparison

Na-free, Sr-Tyrode solution (low frequency signal) vs Na-Tyrode solution (high frequency signal)

Design

Preclinical

Authors

ECE. CarmelietKU Leuven JWJan WillemsUniversity College Ghent

Discussion

Member takes

Implication

Frequency dependence of Purkinje fiber membrane capacity may refine conduction models; leaves open in vivo relevance and requires mammalian confirmation.

Key Points

To determine whether the apparent membrane capacity of cardiac Purkyně fibres varies with the frequency of electrical excitation signals.
Measured apparent membrane capacity using action potential upstrokes of varying frequency in isolated cardiac Purkyně fibres.
Generated high-frequency signals using standard sodium Tyrode solution and low-frequency signals using sodium-free strontium Tyrode solution characterized by slow depolarization (5 V/s) and conduction velocity (15 cm/s).
Assessed fiber cable properties, including internal core resistance, membrane resistance, and space and time constants, under both ionic conditions.
Apparent membrane capacity increased by a factor of 3.77 upon switching from sodium- to strontium-Tyrode, approaching levels determined by the square-current technique.
Passive cable properties, including space and time constants as well as internal core and membrane resistance, remained constant between solution conditions.

Structured PICO

Population

Cardiac Purkinje fibers

Intervention

Na-free, Sr-Tyrode solution (low frequency signal)

Comparator

Na-Tyrode solution (high frequency signal)

Outcome

Apparent membrane capacitysurrogate

The apparent membrane capacity of cardiac Purkinje fibers is frequency-dependent, increasing significantly when measured with a low-frequency signal (Sr-Tyrode) compared to a high-frequency signal (Na-Tyrode).

Cite This Study

Carmeliet et al. (1971) studied this question.

synapsesocial.com/papers/6a7e4073fff18652e232f44c https://doi.org/10.1113/jphysiol.1971.sp009369

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Implication

Frequency dependence of Purkinje fiber membrane capacity may refine conduction models; leaves open in vivo relevance and requires mammalian confirmation.

The frequency dependent character of the membrane capacity in cardiac Purkyně fibres

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

The frequency dependent character of the membrane capacity in cardiac Purkyně fibres

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

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