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:
A device for ablating tissue within the body has an element (224) with an energy emitting region helically wound about and along the axis of the element. The element emits energy to create a lesion in body tissue. A sheath (240) of a non-energy emitting material is movable over the region to adjust the impedance of the region.
Abstract:
An electrode assembly for use in inter-ventricular cardiac mapping includes one or more elongated splines (76) each of which carries a plurality of spaced apart electrodes (22) thereon. The body of each spline is formed of a plurality of alternating electrically conductive layers (86, 98) and the electrically nonconductive layers (88, 100). A separate electrically conductive pathway (94, 102) is provided to connect each of the electrodes to a different one of the conductive layers. Each of the layers is electrically connected to an electrical signal processing device (92) so that signals provided by each of the electrodes can be processed.
Abstract:
Systems and methods for heating body tissue places a multi-function structure (22) having an exterior wall in contact with body tissue. The structure includes an array of electrically conducting electrode segments (44) carried by the exterior wall. An electrically conductive network is coupled to the electrode segments, including at least one electrically conductive path (32) individually coupled to each electrode segment. The systems and methods operate in a first mode during which the network is electrically conditioned to individually sense at each electrode segment local electrical events in tissue, such as electrical potentials, resistivity, or impedance. The systems and methods operate in a second mode during which the network is electrically conditioned, based at least in part upon local electrical events sensed by the electrode segments, to couple at least two electrode segments together to simultaneously trasmit electrical energy to heat or ablate a region of body tissue.
Abstract:
This invention is systems and methods for ablating body tissue use, and electrode (16) for contacting tissue. The electrode (16) is coupled to a source of ablation energy (12) for transmitting ablation energy at a prescribed ablation power level into tissue to form, over a prescribed time period, a therapeutic result. The systems and methods include an element (50) to cool the electrode (16). An input element (100) inputs a desired result, and a processing element (98) retains a function correlating an observed relationship among lesion boundary depth, ablation power level, ablation time and temperature. The processing element (98) compares the desired result to the function and selects an operating condition based upon the comparison to achieve the desired result.