What question did this study set out to answer?

To evaluate whether the clinically observed arrhythmogenic interaction between halothane and catecholamines originates at the single ventricular cell level.

May 1, 1991Anesthesia & Analgesia

Effect of Halothane on Arrhythmogenic Responses Induced by Sympathomimetic Agents in Single Rat Heart Cells

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Why the study?

Does halothane increase arrhythmogenic responses induced by sympathomimetic agents in single rat heart cells?

Key Points

To evaluate whether the clinically observed arrhythmogenic interaction between halothane and catecholamines originates at the single ventricular cell level.
Isolated single rat cardiac myocytes and exposed them to sympathomimetic agents with and without 0.30 mM halothane.
Quantified the incidence of cellular arrhythmogenic markers, specifically interbeat contractile waves, early aftercontractions, and late aftercontractions.
Halothane (0.30 mM) significantly reduced the incidence of interbeat waves and late aftercontractions induced by isoproterenol (1 × 10⁻⁷ M) and norepinephrine (1–3 × 10⁻⁷ M).
Early aftercontractions stimulated by isoproterenol (1 × 10⁻⁷ M), norepinephrine (1–3 × 10⁻⁷ M), and phenylephrine (5–10 × 10⁻⁶ M) showed a statistically significant decrease in the presence of 0.30 mM halothane.

Structured PICO

Does halothane increase arrhythmogenic responses induced by sympathomimetic agents in single rat heart cells?

Population

Single rat heart cells (myocytes)

Intervention

Halothane (0.30 mM) added to sympathomimetics (isoproterenol, norepinephrine, phenylephrine)

Comparator

Sympathomimetics alone

Outcome

Incidence of spontaneous contractile waves (interbeat waves), early aftercontractions, and late aftercontractionssurrogate

Halothane inhibits sympathomimetic-induced arrhythmogenic activity in single rat ventricular cells, suggesting that the clinically observed arrhythmogenicity of this combination likely arises from altered impulse propagation rather than single-cell mechanisms.

Discussion

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Implication

May suppress single-cell arrhythmogenesis in rat myocytes; hypothesis-generating for in vivo mechanisms and should not change practice.

Cite This Study

Zuckerman et al. (1991) studied this question.

synapsesocial.com/papers/6a82dd200f6070defc21e441 https://doi.org/10.1213/00000539-199105000-00005

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Effect of Halothane on Arrhythmogenic Responses Induced by Sympathomimetic Agents in Single Rat Heart Cells

Key Points

Structured PICO

Discussion

Implication

Cite This Study

Effect of Halothane on Arrhythmogenic Responses Induced by Sympathomimetic Agents in Single Rat Heart Cells

Key Points

Structured PICO

Discussion

Implication

Cite This Study

Also Consider

Also Consider