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High-Resolution Endocardial and Epicardial Optical Mapping in a Sheep Model of Stretch-Induced Atrial Fibrillation
Published on: July 29, 2011
Waveform optimization for internal atrial defibrillation: effects of waveform rounding, phase duration, and voltage
B J Kidwai1, J D Allen, M T Harbinson
1Regional Medical Cardiology Center, Royal Victoria Hospital, Belfast, Ireland.
Pacing and Clinical Electrophysiology : PACE
|August 29, 2001
Summary
Rounding biphasic waveforms for internal atrial defibrillation maintains efficacy while reducing energy. The optimal phase duration for this double rounded waveform is 6-10 ms, enabling effective cardioversion with lower energy requirements.
Area of Science:
- Cardiovascular Electrophysiology
- Medical Device Engineering
Background:
- Atrial fibrillation (AF) necessitates effective defibrillation strategies.
- Conventional truncated exponential biphasic waveforms are used for internal atrial defibrillation.
- Optimizing waveform parameters can improve energy efficiency and reduce adverse effects.
Purpose of the Study:
- To compare the efficacy of internal atrial defibrillation using conventional biphasic waveforms with and without waveform rounding.
- To determine the optimal phase duration for a novel double rounded waveform.
- To assess the impact of waveform modifications on delivered energy and cardioversion success.
Main Methods:
- Internal atrial defibrillation was performed in anesthetized sheep using defibrillation catheters.
- Conventional biphasic waveforms were compared with single and double rounded waveforms.
- Waveform parameters, including phase duration and voltage, were systematically varied.
- Cardioversion success rates and delivered energy were recorded.
Main Results:
- Rounding both phases of the biphasic waveform (double rounded) significantly reduced peak voltages, currents, and delivered energy (>21%) without compromising cardioversion success.
- The efficacy of single and double rounded waveforms was comparable to the conventional waveform at specific voltage settings.
- Optimal efficacy for the double rounded waveform was observed at 6-10 ms phase duration, achieving 100% success at 10 ms with reduced delivered energy.
- Successful cardioversion correlated strongly with peak-to-trough voltage swing across different waveform types.
Conclusions:
- The double rounded waveform offers a promising alternative for internal atrial defibrillation, providing similar efficacy to conventional biphasic waveforms but with reduced energy delivery.
- Optimizing phase duration to 6-10 ms is crucial for maximizing the effectiveness of the double rounded waveform.
- Waveform rounding presents a viable strategy for enhancing energy efficiency in internal atrial defibrillation devices.
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