What is the clinical evidence from this study?

Study design: Other. Population: Ventricular automaticity during digitalization (n=27). Intervention: Ouabain administration and imposed pacing rate. Primary outcome: Changes in ventricular automaticity (idioventricular rate, post-pacing depression, ventricular escape time).

What question did this study set out to answer?

To investigate how heart rate influences ventricular automaticity during ouabain administration in dogs.

February 1, 1972Circulation ResearchOpen Access

Relationship of Heart Rate to Ventricular Automaticity in Dogs During Ouabain Administration

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Key result

Transient increases in heart rate enhanced ventricular automaticity during ouabain administration, indicating that heart rate is a critical determinant of early increases in ventricular automaticity.

Why the study?

Does heart rate influence ventricular automaticity during ouabain administration in dogs?

Population

Dogs

Comparison

Ouabain administration combined with ventricular… vs Different pacing rates or baseline automaticity

Design

Preclinical

Authors

SWStephen M. WittenbergUniversity of Bern PGPaul B. GandelUniversité de Bourgogne PHP. M. HoganBuffalo State University

Discussion

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Implication

May warrant heart rate consideration in digitalis toxicity; hypothesis-generating in canine models, needs human validation.

Key Points

To investigate how heart rate influences ventricular automaticity during ouabain administration in dogs.
Assessed spontaneous changes in ventricular automaticity from idioventricular rate in dogs with heart block.
Evaluated post-pacing depression after ventricular pacing in dogs.
Studied vagally induced escape time after atrial pacing in dogs with intact AV conduction.
At 38% of the toxic ouabain dose, significant blunting of post-pacing depression was observed, i.e., reduced depression of the first post-pacing beat.
At 72% of the toxic dose, post-pacing acceleration occurred, shortening the cycle length of the first post-pacing beat.
Ventricular escape time decreased significantly at heart rates of 180-190 beats/min but not at 100 beats/min.

Structured PICO

Does heart rate influence ventricular automaticity during ouabain administration in dogs?

Population

Dogs with heart block or intact AV conduction undergoing ouabain administration and pacing to assess ventricular automaticity.

Intervention

Ouabain administration (digitalization) combined with ventricular or atrial pacing at various rates

Comparator

Different pacing rates (e.g., 100 vs 140-150 vs 180-190 beats/min) or baseline automaticity

Outcome

Changes in ventricular automaticity (measured by idioventricular rate, post-pacing depression, and vagally induced ventricular escape time)surrogate

Heart rate is a critical determinant of early increases in ventricular automaticity during ouabain toxicity, suggesting that faster rates may unmask or exacerbate digitalis-induced arrhythmias.

Cite This Study

Wittenberg et al. (1972) studied Ventricular automaticity during digitalization (n=27). Ouabain administration and imposed pacing rate was evaluated on Changes in ventricular automaticity (idioventricular rate, post-pacing depression, ventricular escape time). Transient increases in heart rate enhanced ventricular automaticity during ouabain administration, indicating that heart rate is a critical determinant of early increases in ventricular automaticity.

synapsesocial.com/papers/6a45acf56f4bbfd563da309e https://doi.org/10.1161/01.res.30.2.167

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Relationship of Heart Rate to Ventricular Automaticity in Dogs During Ouabain Administration

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Relationship of Heart Rate to Ventricular Automaticity in Dogs During Ouabain Administration

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Also Consider

Also Consider