What question did this study set out to answer?

To determine whether myocardial damage and lactate production following direct internal electric countershock result from myocardial ischemia or non-ischemic mechanisms.

April 1, 1987Anesthesiology

Internal Countershock Produces Myocardial Damage and Lactate Production Without Myocardial Ischemia in Anesthetized Dogs

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Why the study?

Does electric countershock applied directly to the heart affect myocardial lactate extraction and blood flow in anesthetized dogs?

Population

13 halothane anesthetized dogs

Comparison

Electric countershock applied directly to the… vs Atrial pacing to a rate of 190-200, both with…

Design

Preclinical

Follow-up

6 minutes

Authors

DGDavid M. GabaVA Palo Alto Health Care System MMMary S. MaxwellStanford University SMS. MerloneUnited States Department of Veterans Affairs

Discussion

Member takes

Implication

Transient lactate production after countershock in dogs suggests possible injury; hypothesis-generating for human defibrillation effects and requires clinical validation.

Key Points

To determine whether myocardial damage and lactate production following direct internal electric countershock result from myocardial ischemia or non-ischemic mechanisms.
Measured myocardial lactate extraction in 13 anesthetized dogs receiving either two 30-joule direct countershocks (n=7) or atrial pacing to 190–200 beats/min with and without vena caval occlusion (n=6).
Quantified regional myocardial blood flow using radiolabeled microspheres and localized myocardial injury via technetium pyrophosphate uptake in six shocked dogs.
Countershock shifted myocardial lactate extraction from a baseline of 36 ± 10% to a negative nadir of -19 ± 15% at 2.5 minutes post-shock (recovering to 10 ± 6% at 6 minutes), whereas pacing showed no change from baseline (41 ± 3%).
Mean myocardial blood flow slightly increased immediately after shock (0.78 ± 0.08 vs. 1.16 ± 0.3 ml·min⁻¹·g⁻¹), with unchanged epicardial-to-endocardial blood flow ratios (0.97 ± 0.05 vs. 0.99 ± 0.08).
Technetium pyrophosphate myocardial damage correlated neither with post-shock absolute blood flow (r = -0.03) nor with pre-to-post shock blood flow changes (r = 0.01).

Structured PICO

Does electric countershock applied directly to the heart affect myocardial lactate extraction and blood flow in anesthetized dogs?

Population

13 halothane anesthetized dogs

Intervention

Electric countershock applied directly to the heart (two countershocks of 30 delivered joules each)

Comparator

Atrial pacing to a rate of 190-200, both with and without occlusion of the vena cava to produce a mean arterial pressure of 40-50 mmHg

Outcome

Global myocardial extraction of lactatesurrogate

Internal countershock in dogs produces transient myocardial lactate production and damage without evidence of myocardial ischemia.

Cite This Study

Gaba et al. (1987) studied this question.

synapsesocial.com/papers/6a892bfc353a6a8ef2a5f9fd https://doi.org/10.1097/00000542-198704000-00005

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Implication

Transient lactate production after countershock in dogs suggests possible injury; hypothesis-generating for human defibrillation effects and requires clinical validation.

Internal Countershock Produces Myocardial Damage and Lactate Production Without Myocardial Ischemia in Anesthetized Dogs

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Internal Countershock Produces Myocardial Damage and Lactate Production Without Myocardial Ischemia in Anesthetized Dogs

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Also Consider

Also Consider