Ablation device and method of using the same
Inventors
Assignees
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Publication Number
US-12349928-B2
Publication Date
2025-07-08
Expiration Date
Abstract
Ablation device including a probe structure 10 having a proximal end 12 and a distal end 14. Probe structure 10 includes a tubular first catheter 16, a tubular second catheter 18 surrounding the first catheter and a tubular guide catheter extending within the first catheter 16. The first catheter 16 carries a cylindrical ultrasonic transducer 20 adjacent its distal end. The transducer 20 is connected to a source of electrical excitation. The ultrasonic waves emitted by the transducer 20 are directed at the heart wall tissue. Once the tissue reaches the target temperature, the electrical excitation is turned on and off to maintain the tissue at the largest temperature. Alternatively, the transducer 20 is subjected to continuous excitation at one power level and upon the tissue reaching the target temperature, the power level of the continuous excitation is switched to a second lower power level.
Core Innovation
The invention relates to an apparatus for applying energy within a body of a living subject using an in-body energy emitter and a power supply. The emitter is configured for placement inside the body, and a housing places the emitter so an output from the emitter is directed to tissue within the body. The power supply supplies energy according to an input power profile that includes a continuous excitation phase followed by an intermittent excitation phase.
In the continuous excitation phase over a first predetermined duration, continuous excitation is provided so the emitter emits energy into the tissue to reach a first temperature that is equal to or higher than a necrosis temperature necessary for necrosis of the tissue. In the intermittent excitation phase over a second predetermined duration, intermittent excitation is provided to cycle between on and off conditions so the tissue oscillates about a second temperature. The first temperature and the second temperature are conceptually controlled by the continuous phase followed by the on/off cycling phase.
The first predetermined duration and the second predetermined duration are based on the emitter used and based on an empirical determination of a temperature of the target tissue without monitoring the temperature of the target tissue. The input power profile is also described as maintaining the collateral temperature substantially constant during the on/off phase, while reducing collateral tissue temperature and unwanted necrosis. The disclosure further indicates applicability to other output power using the same on/off concept.
Claims Coverage
The document provides three independent claims. Across these independent claims, the inventive concept centers on an input power profile with continuous excitation to reach a necrosis temperature followed by intermittent on/off excitation to oscillate about a second temperature, with phase durations empirically determined without monitoring target tissue temperature.
Continuous-to-intermittent input power profile for in-body energy application
A power supply provides input power to an in-body energy emitter according to an input power profile having a total predetermined duration including a continuous excitation phase followed by an intermittent excitation phase, where the continuous excitation phase causes tissue to reach a first temperature equal to or higher than a necrosis temperature, and the intermittent excitation phase cycles between on and off conditions so the tissue oscillates about a second temperature.
Empirically determined phase durations without monitoring tissue temperature
The first predetermined duration and the second predetermined duration are based on the emitter used and on an empirical determination of a temperature of the target tissue without monitoring the temperature of the target tissue.
Constant-level continuous input power and variable-level intermittent input power
During a continuous excitation phase over one predetermined duration, input power is applied from the power supply to cause the energy emitter to output power at a constant level into the tissue, and during an intermittent excitation phase over a separate predetermined duration, input power is applied at a variable level to cause the energy emitter to output power at a variable level into the tissue.
Across the independent claims, coverage is directed to an in-body energy application apparatus in which a power supply drives an emitter using a continuous excitation phase to bring tissue to a necrosis temperature and a subsequent intermittent excitation phase that cycles to make tissue oscillate about a second temperature, with the phase durations predetermined empirically based on the emitter and target tissue temperature without monitoring the target tissue temperature. One independent claim further specifies that the continuous phase uses a constant input level while the intermittent phase uses a variable input level.
Stated Advantages
Reduces collateral tissue temperature and unwanted necrosis.
Maintains the collateral temperature substantially constant during the on/off phase.
Documented Applications
Cardiac ablation using an in-body cylindrical ultrasonic transducer with balloon-supported focusing onto a ring-like focal region near pulmonary vein ostia.
Use of input power cycling (on/off intermittent excitation) to control tissue temperature behavior during ablation, including temperature plots from animal experiments showing collateral temperature behavior.
Applicability to other output powers using the same on/off concept.
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