Pulsed Field Catheter Waveforms to Limit Heating and Stimulation
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Solution Overview
Problem
Existing methods for affecting target tissue via pulsed fields face issues such as undesirable heating and far-field stimulation, as well as limited adaptability across different tissue types, particularly in cardiac applications like atrial and ventricular arrhythmias.
Innovation Solution
A method involving a titrated dose of energy delivered via electrode catheters, with each pulse having a crenelated waveform that includes peak and nadir intervals, mitigating joule energy and enhancing oxidative stress to achieve the desired permeability effect while minimizing side effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high-voltage, short-duration electrical pulses are delivered to induce irreversible electroporation, then the permeability effect on target tissue is improved, but undesirable heating and far-field stimulation occur
Solution Approach 1:
The electrical pulse is segmented into multiple sub-pulses with alternating polarities (biphasic waveform) rather than delivering a single monophasic pulse. This segmentation reduces the net charge delivery and mitigates far-field stimulation while maintaining the electroporation effect on target tissue through the cumulative exposure to high electric field strength.
Solution Approach 2:
The pulse waveform parameters are changed from monophasic to biphasic, with specific control over pulse duration, inter-pulse intervals, and voltage amplitude. By adjusting these parameters, the treatment achieves effective electroporation while reducing Joule heating through the alternating polarity that allows partial relaxation of tissue between phases.
2Object-affected harmful factors
If biphasic stimulation is employed to reduce heating and far-field stimulation, then harmful effects are reduced, but treatment efficiency decreases compared to monophasic stimulation
Solution Approach 1:
The treatment employs periodic biphasic pulses with optimized inter-pulse intervals that allow tissue recovery between phases while maintaining cumulative electroporation effect. The periodic delivery at controlled frequencies ensures adequate time for pore formation and stabilization, improving treatment efficiency compared to traditional monophasic approaches while continuing to reduce harmful effects.
Solution Approach 2:
The system incorporates monitoring of tissue response and delivers adaptive biphasic pulses that adjust amplitude and timing based on detected tissue characteristics. This feedback mechanism optimizes the balance between achieving sufficient permeability effect and minimizing harmful heating, thereby maintaining treatment efficiency while reducing side effects.
3Object-affected harmful factors
If the pulse width is reduced to limit energy delivery, then heating and far-field stimulation are reduced, but the time for pores to remain open decreases, reducing treatment effectiveness
Solution Approach 1:
The biphasic pulse structure performs preliminary electroporation in the first phase, creating initial pores in the cell membrane. The second phase then reinforces and stabilizes these pores, ensuring they remain open for sufficient duration to achieve effective treatment. This preliminary action followed by reinforcement maintains permeability effect despite reduced individual pulse width.
Solution Approach 2:
The two phases of the biphasic pulse are delivered in continuous succession with minimal interruption, maintaining the electroporation process continuously. The first phase initiates pore formation and the second phase sustains and enhances it, ensuring continuous useful action on the target tissue throughout the pulse duration, thereby maintaining treatment effectiveness with shorter overall pulse width.
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
The method effectively transitions target tissue to a nonviable state without compromising structural integrity, reducing heating and far-field stimulation, and adapting to various tissue types.
Implementation Method 1
the target tissue can be affected via the development of electroporation resulting from an electrical field produced adjacent the target tissue by the high-voltage, short-duration electrical pulses
Implementation Method 2
enhancing oxidative stress to achieve the desired permeability effect
Implementation Method 3
mitigating joule energy and enhancing oxidative stress
Data Source
AI summary
Systems and methods are provided for treating a target tissue. Accordingly, an electrode catheter is positioned in proximity to the target tissue and a dose of energy is delivered. The dose of energy includes a set of pulses at a first frequency. Each pulse has a maximal pulse magnitude and a pulse duration associated with a reference pulse and an energy output that is less than the reference pulse. A pulse waveform of each pulse includes a set of peak intervals at a second frequency and interspersed nadir intervals. The duration of each nadir interval is less than a restitution interval of the target tissue, and the second frequency enhances production of an oxidative reaction. The resultant Maxwell stress substantially equals the Maxwell stress that would be produced by the reference pulse, while the oxidative stress is greater than the oxidative stress producible by the reference pulse.