What is the clinical evidence from this study?

Study design: Other. Intervention: Electrophysiological characterization. Primary outcome: Presence and characteristics of the hyperpolarization-activated inward current (I(f)).

What question did this study set out to answer?

The study aims to evaluate the characteristics of the hyperpolarization-activated inward current in human atrial myocardium and investigate electrophysiological heterogeneity in diastolic voltage ranges.

June 1, 1998Cardiovascular ResearchOpen Access

Characterization of the hyperpolarization-activated inward current in isolated human atrial myocytes

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Key result

The hyperpolarization-activated inward current (I(f)) was observed in 95% to 100% of isolated human atrial myocytes, exhibiting properties similar to mammalian pacemaker cells.

Population

Isolated myocytes from 96 human right atrial appendages

Design

Preclinical

Authors

UHUta C. HoppeElectrophysiology

Discussion

Member takes

Implication

May support I(f) heterogeneity as arrhythmia substrate in human atria; leaves open clinical relevance pending targeted studies.

Key Points

The study aims to evaluate the characteristics of the hyperpolarization-activated inward current in human atrial myocardium and investigate electrophysiological heterogeneity in diastolic voltage ranges.
Used whole-cell patch-clamp technique to record hyperpolarization-activated inward current in isolated human atrial myocytes from 96 right atrial appendages.
Evaluated electrophysiological properties including time- and voltage-dependence, block by Cs+, and permeability for K+, Na+, and Li+.
Classified myocytes into three types based on relative current size of I(f) and IK1.
Observations show I(f) in 95% to 100% of myocytes with typical current properties.
I(f) density was significantly higher in myocytes with prominent I(f) compared to those with predominant IK1 (P < 0.05).
Boltzmann distributions yielded an activation threshold between -60 to -70 mV and a half maximal activation at -89.3 +/- 0.7 mV.

Structured PICO

Population

Isolated myocytes from 96 human right atrial appendages.

Exposure

Whole-cell patch-clamp technique (ruptured and perforated patch) and isoproterenol (10(-6) mol/l)

Outcome

Characteristics of the hyperpolarization-activated inward current (I(f)) including activation threshold, half maximal activation, and response to isoproterenolsurrogate

The hyperpolarization-activated inward current (I(f)) is present in most human atrial myocytes and exhibits properties similar to mammalian pacemaker cells, with variable relative current sizes among different myocytes.

Limitations

Whether I(f) may favor spontaneous diastolic depolarization in vivo remains to be defined, as current size is very small under physiological potassium concentrations.

Cite This Study

Uta C. Hoppe (1998) studied this question. Electrophysiological characterization was evaluated on Presence and characteristics of the hyperpolarization-activated inward current (I(f)). The hyperpolarization-activated inward current (I(f)) was observed in 95% to 100% of isolated human atrial myocytes, exhibiting properties similar to mammalian pacemaker cells.

synapsesocial.com/papers/6a6d3086febe604dd707b10b https://doi.org/10.1016/s0008-6363(98)00047-9

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Characterization of the hyperpolarization-activated inward current in isolated human atrial myocytes

Discussion

Member takes

Implication

Key Points

Structured PICO

Limitations

Cite This Study

Characterization of the hyperpolarization-activated inward current in isolated human atrial myocytes

Discussion

Member takes

Implication

Key Points

Structured PICO

Limitations

Cite This Study

Also Consider

Also Consider