Multiphase RF Ablation Generator for Crosstalk-Resistant Contact Detection
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Solution Overview
Problem
Existing multi-electrode ablation catheters face inefficiencies in current differentiation using class A amplifiers and struggle with crosstalk currents, which affect the accuracy and effectiveness of tissue contact detection and ablation procedures.
Innovation Solution
A multi-electrode ablation catheter system utilizing Class-D amplifiers and a common frequency with individually varied phases for electrodes, coupled with a processor to adjust phases and amplitudes based on return signals, minimizes crosstalk and ensures effective tissue contact detection and ablation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If class A amplifiers are used to generate alternating currents for electrode differentiation, then current differentiation is achieved, but energy efficiency deteriorates significantly
Solution Approach 1:
The patent changes the operational parameter of the amplifier from class A to class D, fundamentally altering the amplification method. Class D amplifiers use pulse width modulation (PWM) to achieve high efficiency while maintaining the ability to differentiate currents across multiple electrodes, thus resolving the contradiction between measurement precision and energy efficiency.
2Measurement precision
If multiple alternating currents are generated with unique frequencies for each electrode, then electrode location identification is improved, but crosstalk currents increase
Solution Approach 1:
The patent employs asymmetric phase modulation where electrodes are driven with different phase angles relative to a reference electrode. This asymmetric phase distribution creates distinct current signatures for each electrode while the differential measurement approach cancels out common-mode crosstalk currents, achieving both precise location identification and crosstalk reduction.
3Ease of operation
If all electrodes are activated simultaneously with the same voltage, then simple unipolar energy delivery is achieved, but bipolar energy delivery and contact detection capability are lost
Solution Approach 1:
The patent implements periodic switching between different activation modes: a first period activates all electrodes simultaneously for simple unipolar ablation, while a second period applies differential activation patterns to specific electrode pairs for bipolar energy delivery and contact detection. This periodic alternation between modes enables the system to achieve both operational simplicity and detection reliability as needed.
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 system enhances the efficiency of tissue contact detection and ablation by reducing crosstalk currents and improving the accuracy of electrode-tissue contact verification, thereby optimizing the ablation process.
Implementation Method 1
The RF delivery unit may transmit unipolar energy to the plurality of electrodes... transmit bipolar energy to the electrodes... applying ablative radiofrequency (RF) energy to a patient's tissue
Implementation Method 2
measuring voltages and currents between the electrodes and the back patches... measuring alternating currents from the electrode to back patches on the patient's skin
Implementation Method 3
modulating the alternating current injected into the electrodes with a frequency, which is selected to be unique for a given electrode... the phases of the currents flowing through the electrodes are individually varied
Data Source
AI summary
A radio frequency (RF) ablation system is disclosed including signal generator circuitry and control circuitry. The signal generator circuitry is configured to generate a plurality of RF ablation current signals each having a respective phase and a respective amplitude. The control circuitry is configured to reduce crosstalk between a first RF ablation signal of the plurality of RF ablation current signals and a second RF ablation signal of the plurality of RF ablation current signals by adjusting the respective phase of the first RF ablation signal in relation to the respective phase of the second RF ablation signal such that the respective phase of the first RF ablation signal is different than the respective phase of the second RF ablation signal.