Catheter Cable Feedback Circuit for Ablation Leakage Current
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Solution Overview
Problem
Existing ablation systems face challenges in reducing leakage currents to safe levels, particularly in catheter cables used for cryoablation, pulsed field ablation, and radio-frequency ablation, which can exceed safety standards due to distributed capacitance and accidental connections, posing electrical shock hazards and signal interference.
Innovation Solution
Implementing a leakage-current processing circuit with a current sensor and signal-processing circuit to apply a Fourier transform and energy minimization algorithm, generating a correction current to counteract leakage currents, ensuring they remain below safety thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If distributed capacitance in catheter cables is increased to enable therapy signal transmission, then signal transmission capability is improved, but leakage current increases beyond safety standards
Solution Approach 1:
The patent converts the harmful leakage current into a useful signal by using a toroidal coil sensor to detect the magnetic field generated by the leakage current. The detected signal is then processed through Fourier transform and energy minimization algorithms to generate a correction current that counteracts the original leakage current, thereby transforming the harmful effect into a controllable and eliminable parameter.
Solution Approach 2:
The system implements a closed-loop feedback mechanism where the leakage current is continuously monitored by the toroidal coil sensor, processed by the signal processing circuit to determine the required correction, and then applied back through the sleeve capacitor to counteract the original leakage current. This feedback loop ensures that leakage current is actively maintained below safety thresholds.
2Reliability
If leakage current is reduced to safe levels through traditional isolation methods, then patient safety is improved, but signal integrity and therapy effectiveness deteriorate
Solution Approach 1:
The patent introduces a toroidal coil sensor as an intermediary element that couples to the catheter cable through magnetic field interaction rather than direct electrical contact. This intermediary approach allows leakage current detection and correction without creating direct galvanic paths that would compromise signal integrity or require traditional isolation methods that degrade therapy effectiveness.
3Object-affected harmful factors
If active leakage current correction circuits are added to ablation systems, then leakage current reduction is improved, but device complexity increases
Solution Approach 1:
The signal processing circuit performs multiple functions: it detects leakage current spectral content through Fourier transform, calculates the required correction current through energy minimization algorithms, and generates the correction signal. This multi-functional approach consolidates what could be multiple separate circuits into a single integrated system, reducing overall device complexity while achieving effective leakage current reduction.
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
Effectively reduces leakage currents to safe levels, meeting international safety standards and maintaining signal integrity, thereby preventing electrical shocks and signal distortion.
Implementation Method 1
a toroidal-coil sensor AC-coupled to a catheter cable
Implementation Method 2
a sleeve-capacitor coupler, both AC-coupled to the catheter cable
Data Source
AI summary
Methods and apparatus for monitoring and actively reducing leakage currents flowing on patient applied parts used in ablation therapy. In an example, a signal-processing circuit connected between a toroidal-coil sensor and a sleeve-capacitor coupler, both AC-coupled to the catheter cable, applies a Fourier transform and an energy minimization algorithm to the output of the toroidal-coil sensor to determine amplitudes and phases for frequency components of the signal applied to the sleeve-capacitor coupler. A corresponding current coupled through the sleeve-capacitor coupler into the catheter cable counteracts the leakage current to force the total non-therapy electrical current flowing on the patient applied parts to a level that is lower than a fixed threshold value, e.g., selected in accordance with an applicable standard.