Abstract:
This invention is systems and methods that ablate body tissue using an electrode (16) for contacting tissue at a tissue electrode interface to transmit ablation energy at a determinable power level. The systems and methods include an element (50) to remove heat from the electrode (16) at a determinable rate. The systems and methods employ a processing element (98) to derive a prediction of the maximum tissue temperature condition occurring beneath the tissue electrode interface. The processing element (98) controls the power level of ablation energy transmitted by the electrode (16), or the rate at which the electrode (16) is cooled, or both, based, at least in part, upon the maximum tissue temperature prediction.
Abstract:
Analog or digital systems (10) and methods generate a composite signal derived from a biological event in a time sequential fashion. A first set of signals derived from a biological event using a first group of sensors (20) during a first time interval is input. A second set of signals derived from the biological event during a second time interval sequentially after the first time interval using a second group of sensors (36) is input. The second group of sensors has at least one common sensor that is part of the first group and other sensors that are not part of the first group. The first and second sets of signals are time aligned using signals sensed by the at least one common sensor, thereby generating the composite signal. The time alignment is done by shifting the first and second sets of signals either with or without computing a time difference between them.
Abstract:
Systems and methods employ an energy emitting electrode (16) to heat tissue. The systems and methods control the application of energy to the electrode (16) using adjustments that take into account, in a non-linear fashion, changes in monitored operating conditions.
Abstract:
Systems and methods well suited for use in catheter based tissue ablation systems employ thermocouples (80) for temperature sensing at an energy emitter site (30). The sensed temperature is used to control the energy output from the energy source to maintain tissue temperature within desired parameters. The systems combine accuracy with compact, low profile construction.
Abstract:
This invention is a system and associated method to ablate body tissue using multiple emitters (30) of ablating energy. The system and method convey ablating energy individually to each emitter (30) in a sequence of power pulses. The system and method periodically sense the temperature of each emitter (30) and compare the sensed temperatures to a desired temperature established for all emitters (30) to generate a signal individually for each emitter (30) based upon the comparison. The system and method individually vary the power pulse to each emitter (30) based upon the signal for that emitter to maintain the temperatures of all emitters essentially at the desired temperature during tissue ablation.
Abstract:
Systems and methods examine heart tissue morphology using three or more spaced apart electrodes (38), at least two of which are located within the heart (12) in contact with endocardial tissue. The systems and methods transmit electrical current through a region of heart tissue lying between selected pairs of the electrodes (38), at least one of the electrodes (38) in each pair being located within the heart (12). The systems and methods derive the electrical characteristic of tissue lying between the electrode (38) pairs based, at least in part, upon sensing tissue impedances. The systems and methods make possible the use of multiple endocardial electrodes (38) for making multiple measurements of the electrical characteristics of heart tissue. Multiplexing can be used to facilitate date processing. The systems and methods almost make possible the identification of regions of low relative electrical characteristics, indicative of infarcted tissue, without invasive surgical techniques.
Abstract:
Electrode assemblies and associated systems employ a nonporous wall (22) having an exterior for contacting tissue. The exterior peripherally surrounds an interior area. The wall is essentially free of electrically conductive material. The wall is adapted to assume an expanded geometry having a first maximum diameter and a collapsed geometry having a second maximum diameter less than the first maximum diameter. The assemblies and systems include a lumen (34) that conveys a medium containing ions into the interior area. An element free of physical contact with the wall couples the medium within the interior area to a source of electrical energy to enable ionic transport of electrical energy from the source through the medium to the wall for capacitive coupling to tissue contacting the exterior of the wall.
Abstract:
Systems and methods for heating or ablating tissue use a multifunctional electrode assembly (20). The electrode assembly includes a wall (22) comprising an electrically conductive material peripherally surrounding an interior area. The wall has an interior surface facing the interior area and an oppositely facing exterior surface. A first element operatively associated with the exterior surface of the wall is adapted to carry out a first predetermined electrical transmitting or sensing function affecting body tissue. A second element operatively associated with the interior surface of the wall is adapted to carry out, independent of the first element, a second predetermined electrical transmitting or sensing function affecting body tissue different than the first predetermined electrical function.
Abstract:
Systems for ablating body tissue comprise a family of electrode assemblies. Each electrode assembly (22) includes an extruded wall carrying an amount of electrically conductive material co-extruded within it. The extruded walls possess different electrical resistivity values by virtue of different amounts of electrically conductive material co-extruded within the walls. The systems also include means for specifying, among the family, use of the electrode assemblies according to a function that correlates desired tissue ablation effects with electrical resistivity values of the walls.