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Minimum energy single-shock internal atrial defibrillation in sheep
Amy M Goodman1, Merlise A Clyde, Donald S Burdick
1Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708, USA.
Summary
Low-energy atrial defibrillation aims for painless shocks below 1 Joule. However, this study found that the energy required to defibrillate the atria 10% of the time (ED10) ranged from 1.2 to 5.8 Joules in sheep, suggesting low-energy defibrillation may not be feasible.
Area of Science:
- Cardiology
- Medical Devices
- Electrophysiology
Background:
- Internal atrial defibrillation requires shocks below the pain threshold (<1 Joule).
- Low-energy defibrillation is theoretically possible at the lower end of the dose-response curve.
- Atrial fibrillation (AF) necessitates effective and tolerable defibrillation strategies.
Purpose of the Study:
- To test the hypothesis that the atrial defibrillation energy for 10% success (ED10) is less than 1 Joule.
- To evaluate the feasibility of low-energy atrial defibrillation in a preclinical model.
- To determine ED10 and ED50 values for low-energy shocks in sheep with chronic AF.
Main Methods:
- Seven sheep with induced chronic atrial fibrillation (AF) were studied.
- Low-energy defibrillation shocks were delivered using coronary sinus (CS) to superior vena cava (SVC) leads.
- Logistic regression was used to calculate the ED10 and ED50 (energy for 50% success).
Main Results:
- The mean ED10 to ED50 ratio was 0.50, indicating ED10 was half of ED50.
- The calculated ED10 values ranged from 1.2 to 5.8 Joules.
- These energies exceed the estimated pain threshold for well-tolerated shocks.
Conclusions:
- Low-energy atrial defibrillation, aiming for energies below 1 Joule, may not be feasible.
- The study's findings challenge the possibility of painless, single-shock low-energy atrial defibrillation.
- Further research is needed to optimize defibrillation strategies for atrial fibrillation.