Multi-channel RF energy delivery with coagulum reduction

Abstract

A system for efficient delivery of radio frequency (RF) energy to cardiac tissue with an ablation catheter used in catheter ablation, with new concepts regarding the interaction between RF energy and biological tissue. In addition, new insights into methods for coagulum reduction during RF ablation will be presented, and a quantitative model for ascertaining the propensity for coagulum formation during RF ablation will be introduced. Effective practical techniques are presented for multichannel simultaneous RF energy delivery with real-time calculation of the Coagulum Index, which estimates the probability of coagulum formation. This information is used in a feedback and control algorithm which effectively reduces the probability of coagulum formation during ablation. For each ablation channel, electrical coupling delivers an RF electrical current through an ablation electrode of the ablation catheter and a temperature sensor is positioned relative to the ablation electrode for measuring the temperature of cardiac tissue in contact with the ablation electrode. A current sensor is provided within each channel circuitry for measuring the current delivered through said electrical coupling and an information processor and RF output controller coupled to said temperature sensor and said current sensor for estimating the likelihood of coagulum formation. When this functionality is propagated simultaneously through multiple ablation channels, the resulting linear or curvilinear lesion is deeper with less gaps. Hence, the clinical result is improved due to improved lesion integrity.

Description

Background of the invention [0001] Radiofrequency energy can be used to treat certain heart abnormalities such as muscle fibrillation by ablating heart tissue. RF energy is delivered by the RF generator in two phases: (i) the "ramp up" phase, in which a relatively large amount of power is delivered to the ablation electrode until a desired value is sensed by a thermocouple or thermistor. until the set temperature, and (ii) a "regulation" phase, in which power is still being delivered, but regulated at a lower level to maintain the desired set temperature. This target temperature is predetermined by the operator and is typically 50° to 55°C for ablation of cardiac tissue. [0002] Most RF generators have a software module that runs concurrently on a portable computer during RF energy delivery to record ablation events. Typically, the parameters recorded are sensed impedance, delivered power, and tissue temperature sensed by a thermistor or thermocouple. Currently, this infor...

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Problems solved by technology

Therefore, rapidly alternating impedance values ​​cause the output power waveform to fluctuate rapidly

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