Ablation Catheter Electrode Assembly for Fast, Controlled PVI
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Solution Overview
Problem
Existing ablation catheters face challenges in accurately measuring tissue temperature and impedance, leading to potential tissue damage and incomplete lesion formation during RF ablation procedures, particularly in treating complex cardiac arrhythmias like persistent atrial fibrillation, with high rates of acute PV reconnection and collateral tissue damage.
Innovation Solution
An ablation catheter system with an elongated body, an electrode assembly featuring a shell with apertures and micro-elements extending through the inner chamber, configured for precise tissue contact and continuous irrigation, allowing for improved temperature sensing, impedance measurement, and reduced RF ablation time, while minimizing tissue breach and steam pops.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional RF ablation is used with moderate power (20-40W) for long duration (20-40 seconds), then lesions are formed, but the procedure time is extended and acute PV reconnection occurs frequently (15-22%)
Solution Approach 1:
The patent applies parameter changes by delivering high power (70-100W) for a short duration (3-6 seconds) instead of moderate power for long duration. This transforms the ablation parameters to achieve rapid lesion formation with better durability and reduced reconnection rates, directly resolving the contradiction between procedural success and time loss
Solution Approach 2:
The patent implements periodic action through multiple discrete RF applications (typically 3-5 applications per pulmonary vein) with brief intervals between them. Each application delivers high power for 3-6 seconds, creating a series of effective lesions that collectively achieve complete isolation, thereby reducing total procedure time while maintaining high success rates
2Temperature
If irrigation is applied to cool the electrode and tissue, then overheating is prevented, but temperature sensing accuracy is reduced due to cooling bias
Solution Approach 1:
The patent introduces an intermediary solution by placing the temperature sensor within the electrode shaft rather than at the electrode tip surface. This intermediate positioning allows the sensor to measure tissue temperature through the electrode wall, avoiding direct exposure to irrigation fluid cooling while still accurately reflecting tissue temperature at the ablation site
Solution Approach 2:
The patent applies nesting by embedding the temperature sensor inside the electrode assembly structure. The sensor is positioned within the electrode shaft and measures temperature through the electrode wall, creating a nested configuration that protects the sensor from irrigation fluid while maintaining close proximity to the tissue for accurate measurement
3Productivity
If high power (70-100W) is delivered for short duration (3-6 seconds), then ablation efficiency is improved, but tissue damage and steam pops may occur
Solution Approach 1:
The patent implements feedback control by continuously monitoring tissue impedance and temperature during each RF application. The system uses this real-time feedback to detect early signs of excessive heating or steam pop formation, automatically adjusting or terminating the RF delivery to prevent tissue damage while maintaining high ablation efficiency
Solution Approach 2:
The patent applies dynamics by making the RF power delivery adaptive rather than static. The system dynamically adjusts power levels based on real-time tissue conditions, contact force, and temperature feedback, allowing high power delivery when conditions are favorable while automatically reducing power when risk of damage increases, thereby resolving the contradiction between efficiency and safety
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 achieves enhanced procedural success with 80% less RF ablation time, reduced adverse events, and improved lesion formation, ensuring complete pulmonary vein isolation with minimal collateral damage and shorter procedure times.
Implementation Method 1
RF lesion formation results from two thermal heating phases; resistive and conductive heating. Resistive heating is highly dependent on RF power immediately creating a hot spot ~2mm from the tip.
Implementation Method 2
This resistive heating phase creates a heat source that extends passively to deeper tissue layers during the conductive phase. Conductive heating is time dependent, with heat conducted from the hot spot into the deeper layers of the myocardium.
Implementation Method 3
Irrigation provides many benefits including cooling of the electrode and tissue which prevents overheating of tissue that can otherwise cause the formation of char and coagulum and even steam pops.
Data Source
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Figure 3A~3B
AI summary
An ablation catheter system for drug refractory symptomatic paroxysmal atrial fibrillation (PAF). The system can include an elongated body; an electrode assembly comprising a shell configured with an inner chamber and a wall defining a proximal portion and a distal portion, the wall of the distal portion having at least one aperture; and a micro-element extending through the inner chamber between the proximal portion and the distal portion, the micro-element having a distal end received in the at least one aperture, the distal end being at least coextensive with an outer surface of the wall. The system is configured to achieve acute procedural PVI success for all patients of a predetermined patient population suffering from PAF.