March 1, 2021Pflügers Archiv - European Journal of PhysiologyOpen Access

The conduction velocity-potassium relationship in the heart is modulated by sodium and calcium

Q: What is the clinical evidence from this study?

Study design: Other. Population: Hyperkalemia (n=85). Intervention: Elevated Sodium and Calcium vs. 145 mM Na+ and 1.25 mM Ca2+. Primary outcome: Conduction velocity during 10-mM K+ perfusion.

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Key result

Combined sodium and calcium elevation mitigates conduction slowing during severe hyperkalemia in guinea pig hearts.

n=85

Why the study?

It remained unknown whether elevating extracellular sodium and calcium, or altering gap junctional coupling, modulates cardiac conduction velocity as a function of potassium.

Population

Optically mapped, Langendorff-perfused guinea pig hearts and a computational model

Comparison

Varying sodium, calcium, and potassium concentrations with or without carbenoxolone

Design

Ex vivo experimental and computational modeling study

Authors

DKD. Ryan KingCarilion Clinic MEMichael EntzCarilion Roanoke Memorial Hospital GBGrace A. BlairJohns Hopkins University

Discussion

Member takes

Implication

Hypothesis-generating for ephaptic modulation in hyperkalemia; should not yet change clinical practice.

Structured PICO

Population

Adult male Hartley albino guinea pigs (n=85, 800–1,200 g, 14–16 months old) and a computational model of cardiac conduction.

Intervention

Perfusion with varying concentrations of Na+ (145 to 155 mM), Ca2+ (1.25 to 2.0 mM), and K+ (4.6, 6.4, 8.0, and 10 mM), with or without gap junction inhibition using 30-μM carbenoxolone.

Comparator

Baseline/standard crystalloid perfusate (145 mM Na+, 1.25 mM Ca2+, 4.6 mM K+).

Outcome

Cardiac conduction velocity (longitudinal and transverse) and perinexal width.surrogate

Elevating extracellular sodium and calcium attenuates hyperkalemia-induced conduction slowing by enhancing ephaptic coupling.

Limitations

The gap junction inhibitor carbenoxolone has documented non-gap junction-related off-target effects
Potential species differences in normal plasma electrolyte concentrations between murine and guinea pig models
The atria and sino-atrial node were removed from the isolated heart preparation
The computational model was not precisely tuned to replicate all experimental findings regarding conduction velocity slowing

Cite This Study

King et al. (2021) studied Hyperkalemia (n=85). Elevated Sodium and Calcium vs. 145 mM Na+ and 1.25 mM Ca2+ was evaluated on Conduction velocity during 10-mM K+ perfusion. Combined elevation of extracellular sodium and calcium significantly mitigated cardiac conduction slowing during severe hyperkalemia in isolated guinea pig hearts.

synapsesocial.com/papers/6a164116a2d9d2b88ec50d52 https://doi.org/10.1007/s00424-021-02537-y

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The conduction velocity-potassium relationship in the heart is modulated by sodium and calcium

Discussion

Member takes

Implication

Structured PICO

Limitations

Cite This Study

The conduction velocity-potassium relationship in the heart is modulated by sodium and calcium

Discussion

Member takes

Implication

Structured PICO

Limitations

Cite This Study

Also Consider

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