High-Frequency Unipolar Electroporation Ablation to Reduce Muscle Stimulation
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Solution Overview
Problem
Unipolar irreversible electroporation (IRE) is challenging due to low patient capacitance and high impedance, leading to inefficient current distribution and muscle stimulation issues when using high-frequency electrical pulses for cardiac ablation.
Innovation Solution
Implementing high-frequency pulse trains (0.5-10 MHz) with amplitudes of 1-3 kV and currents of 15-45 Amps, and selecting body-surface patches to minimize muscle stimulation by monitoring movement thresholds during ablation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high-frequency electrical pulses are used for unipolar IRE cardiac ablation, then ablation efficiency is improved, but muscle stimulation and skin damage occur
Solution Approach 1:
The patent applies periodic electrical pulse trains at high frequencies (0.5-10 MHz) to achieve efficient cardiac ablation. The periodic nature of the pulses allows for controlled energy delivery that penetrates tissue effectively while the cyclical application enables thermal diffusion periods between pulses, reducing cumulative thermal damage to surrounding structures and minimizing muscle stimulation.
Solution Approach 2:
The patent utilizes parameter changes by varying pulse frequency (0.5-10 MHz), voltage amplitude (1-3 kV), and pulse width to optimize ablation efficiency while controlling harmful effects. By adjusting these parameters, the system achieves deep tissue penetration and effective lesion formation without excessive muscle stimulation or skin damage, as the parameter optimization balances energy delivery with tissue tolerance.
2Length of moving object
If high voltage and current are applied to achieve deeper ablation, then lesion depth is improved, but risk of skin damage and collateral tissue injury increases
Solution Approach 1:
The periodic application of high-voltage pulses allows for deep lesion formation through cumulative thermal effects while providing intermittent cooling periods. The pulse trains deliver sufficient energy for deep penetration, but the periodic nature enables heat diffusion away from the electrode-skin interface, preventing excessive skin damage and collateral injury despite the use of high voltages (1-3 kV).
Solution Approach 2:
The continuous delivery of pulse trains maintains effective ablation action throughout the treatment duration, ensuring deep and uniform lesion formation. The continuous high-frequency pulsing (0.5-10 MHz) sustains the ablation process at the required depth while the brief inter-pulse intervals allow for thermal management, preventing runaway heating and collateral damage.
3Reliability
If high-frequency pulse trains are used to overcome patient capacitance issues, then current distribution is improved, but muscle stimulation occurs
Solution Approach 1:
The high-frequency periodic pulse trains (0.5-10 MHz) overcome patient capacitance by delivering energy faster than the capacitance can block, achieving reliable current distribution through the tissue. The periodic nature at these frequencies allows the capacitive reactance to be effectively bypassed, ensuring consistent current delivery to the target tissue while the short pulse duration and frequency characteristics minimize muscle stimulation.
Solution Approach 2:
The patent changes the frequency parameter to the high range (0.5-10 MHz) to fundamentally alter how current distributes through the patient's body capacitance. This parameter change transforms the electrical interaction, allowing effective current penetration and distribution that overcomes capacitive blocking, while the specific frequency selection avoids resonant frequencies that would cause muscle stimulation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Achieves deeper ablation lesions with reduced skin damage and muscle stimulation, enhancing the efficiency and safety of unipolar IRE cardiac ablation.
Implementation Method 1
The ablation power generator is configured to generate multiple electrical pulse trains having a pulse frequency of at least 0.5 megahertz... so as to electroporate tissue of the body part
Implementation Method 2
Irreversible electroporation (IRE) applies short electrical pulses that generate high enough electrical fields (typically greater than 450 Volts per centimeter) to irreversibly damage the cells. The pulses increase the resting transmembrane potential, so that nanopores form in the plasma membrane.
Implementation Method 3
The processor is configured to provide a measurement of movement... representative of muscle stimulation in response to applying the electrical pulse trains
Data Source
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AI summary
An electroporation ablation system includes a probe to be inserted into a body part of a living subject, and including a distal end including at least one electrode, body-surface patches to be applied to a skin surface, an ablation power generator to apply at least one first electrical pulse train between the electrode(s) and first one(s) of the body-surface patches, and a processor to provide a measurement of movement of the living subject responsively to applying the first electrical pulse train(s) between the electrode(s) and the first one(s) of the body-surface patches, and select second one(s) of the body-surface patches responsively to the measurement of movement, and wherein the ablation power generator is configured to apply at least one second electrical pulse train between the electrode(s) and the second one(s) of the body-surface patches.