What question did this study set out to answer?

To characterize the sequential macroscopic and histopathologic cardiac changes induced by single transthoracic damped sinusoidal waveform defibrillator shocks across a range of current doses.

February 1, 1978American Journal of Veterinary Research

Sequential Cardiac Morphologic Alterations Induced in Dogs by Single Transthoracic Damped Sinusoidal Waveform Defibrillator Shocks

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Authors

JVJohn F. Van VleetPurdue University West Lafayette WTWillis A. TackerBaylor College of Medicine LGL. A. GeddesElectrophysiology

Discussion

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Implication

High-energy transthoracic shocks caused mortality in dogs; leaves open safe energy thresholds for clinical defibrillation.

Key Points

To characterize the sequential macroscopic and histopathologic cardiac changes induced by single transthoracic damped sinusoidal waveform defibrillator shocks across a range of current doses.
Assigned 56 dogs across 8 dosage groups to receive either no shock or a single transthoracic shock ranging from 1 to 20 A/kg.
Euthanized surviving dogs (n=48) at predetermined intervals (2 hours, 1 day, 2 days, 4 days, 2 weeks, or 8 weeks) to evaluate gross and microscopic heart pathology.
Mortality was 20% in each of the three highest dose groups (12, 15, and 20 A/kg; 8 total deaths), with macroscopic damage appearing at ≥6 A/kg (2 of 5 dogs) and microscopic injury detected at ≥3 A/kg (1 of 5 dogs).
Acute lesions initially showed subepicardial myofibrillar degeneration with contraction bands, transitioned to necrosis with calcification and macrophage infiltration by day 4, and healed into small, pale, fibrous scars by week 8.
Defibrillator shocks demonstrated wide margins of safety relative to the defibrillation threshold, requiring 3-fold, 6-fold, and 12-fold suprathreshold doses to cause microscopic damage, macroscopic damage, and death, respectively.

Cite This Study

Vleet et al. (1978) studied this question.

synapsesocial.com/papers/6a72d24faa61a8b0231ae35a https://doi.org/10.2460/ajvr.1978.39.02.271

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Sequential Cardiac Morphologic Alterations Induced in Dogs by Single Transthoracic Damped Sinusoidal Waveform Defibrillator Shocks

Discussion

Member takes

Implication

Key Points

Cite This Study

Sequential Cardiac Morphologic Alterations Induced in Dogs by Single Transthoracic Damped Sinusoidal Waveform Defibrillator Shocks

Discussion

Member takes

Implication

Key Points

Cite This Study

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