What is the clinical evidence from this study?

Population: Chronic atrioventricular block. Intervention: Pentobarbital and chloralose anesthesia vs. Conscious state. Primary outcome: Atrial effective refractory period (AERP), atrial and ventricular rates, and mean blood pressure.

What does this research mean for the field?

Pentobarbital enhances quinidine-induced lengthening of the atrial effective refractory period while diminishing its chronotropic effects, whereas chloralose attenuates quinidine-induced refractoriness lengthening. Novelty: ClaimNovelty.INCREMENTAL. Consensus alignment: ConsensusAlignment.NEUTRAL.

What question did this study set out to answer?

To assess how pentobarbital and chloralose anesthesia influence baseline cardiac electrophysiological and hemodynamic parameters, as well as quinidine-induced changes in these variables.

February 1, 1991Journal of Cardiovascular Pharmacology

Influence of Pentobarbital and Chloralose Anesthesia on Quinidine-Induced Effects on Atrial Refractoriness and Heart Rate in the Dog

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Key result

Pentobarbital enhances quinidine-induced AERP prolongation, while chloralose blunts this electrophysiologic effect in canine models.

Why the study?

The influence of pentobarbital and chloralose anesthesia on quinidine-induced effects on atrial refractoriness and heart rate in dogs with chronic atrioventricular block was unclear.

Does pentobarbital or chloralose anesthesia alter the electrophysiological and hemodynamic effects of quinidine in dogs with chronic AV block?

Population

Dogs with chronic atrioventricular block and implanted atrial pacing electrodes

Comparison

Pentobarbital or chloralose anesthesia versus conscious state during quinidine administration

Design

Preclinical experimental study

Authors

MBMichel BoucherCanadian Agency for Drugs and Technologies in Health CDClaude DubrayInserm JLJ. H. LiInserm

Discussion

Member takes

Implication

Anesthetics may confound quinidine electrophysiology in canine models; supports conscious animals for future antiarrhythmic testing.

Key Points

To assess how pentobarbital and chloralose anesthesia influence baseline cardiac electrophysiological and hemodynamic parameters, as well as quinidine-induced changes in these variables.
Studied canine models with chronic atrioventricular block and implanted atrial pacing electrodes under conscious and anesthetized conditions.
Administered cumulative doses of quinidine (2, 4, and 8 mg/kg) achieving plasma concentrations between 2.7 ± 0.6 and 6.3 ± 1.3 μg/ml following pentobarbital (30 mg/kg) or chloralose (100 mg/kg) pretreatment.
In conscious dogs, quinidine dose-dependently increased atrial effective refractory period (AERP) by up to 21%, 28%, and 46%, increased atrial rate by 49%, 65%, and 72%, and decreased mean blood pressure by 19%, 33%, and 43%.
Pentobarbital augmented quinidine-induced AERP prolongation by up to 10, 21, and 25 ms and blunted atrial chronotropic responses (reducing increases by 38, 53, and 67 beats/min), whereas chloralose attenuated AERP prolongation (by 5, 12, and 22 ms) without modifying chronotropic effects.
Neither anesthetic altered quinidine plasma concentrations or the drug's hypotensive actions.

Structured PICO

Does pentobarbital or chloralose anesthesia alter the electrophysiological and hemodynamic effects of quinidine in dogs with chronic AV block?

Population

Dogs with chronic atrioventricular block and implanted atrial pacing electrodes used to investigate the effects of anesthetics on quinidine-induced cardiac effects.

Intervention

Pentobarbital (30 mg/kg) or chloralose (100 mg/kg) anesthesia, followed by quinidine at cumulative doses of 2, 4, and 8 mg/kg

Comparator

Conscious dogs receiving quinidine at cumulative doses of 2, 4, and 8 mg/kg

Outcome

Atrial effective refractory period (AERP), atrial and ventricular rates, and mean blood pressuresurrogate

Anesthetics such as pentobarbital and chloralose significantly alter the electrophysiological effects of quinidine in dogs, highlighting the importance of using conscious animal models for antiarrhythmic drug testing.

Limitations

Difficulties involved in comparing experimental results from different studies and transposing experimental results to human beings due to complex autonomic nervous system interactions.

Cite This Study

Boucher et al. (1991) studied Chronic atrioventricular block. Pentobarbital and chloralose anesthesia vs. Conscious state was evaluated on Atrial effective refractory period (AERP), atrial and ventricular rates, and mean blood pressure. Pentobarbital increased quinidine-induced lengthening of the atrial effective refractory period and reduced chronotropic effects, whereas chloralose reduced AERP lengthening.

synapsesocial.com/papers/6ab9c4b9b0c01e1eb975ba2e https://doi.org/10.1097/00005344-199102000-00004

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Influence of Pentobarbital and Chloralose Anesthesia on Quinidine-Induced Effects on Atrial Refractoriness and Heart Rate in the Dog

Discussion

Member takes

Implication

Key Points

Structured PICO

Limitations

Cite This Study

Influence of Pentobarbital and Chloralose Anesthesia on Quinidine-Induced Effects on Atrial Refractoriness and Heart Rate in the Dog

Discussion

Member takes

Implication

Key Points

Structured PICO

Limitations

Cite This Study

Also Consider

Also Consider