Abstract:
This invention is systems and methods to examine heart tissue morphology using three or more spaced electrodes (38), at least two of which are located within the heart in contact with endocardial tissue. The systems and methods transmit electrical current through a region of heart tissue lying between selected pairs of electrodes (224), at least one of the electrodes in each pair being located within the heart. The systems and methods derive the electrical characteristic of tissue between the electrode pairs (206) based, at least in part, upon sensing tissue impedances.
Abstract:
This invention concerns systems and methods for locating an operative element (12) within an interior body space use a locating probe (14), which includes at least one transmitting element to transmit an electric waveform output within at least a portion of the space. The systems and methods also use a sensing element (16), which is adapted to be carried by the operative element to sense a local electric waveform within the space. A processing element coupled to the sensing element generates a processed output that locates the sensing element relative to the locating probe based, at least in part, upon a differential comparison of the waveform output and the sensed local waveform.
Abstract:
Multiple electrode support structures (20(a)) have asymmetric geometries, either axially, or radially, or both. The asymmetric support structures are assembled from spline elements (51, 58) that extend between a distal hub (24) and a proximal base (26). In one embodiment, the spline elements (51, 58) are circumferentially spaced about the distal hub (24) in a radially asymmetric fashion, creating a greater density of spline elements in one region of the structure than in another region. In the same or another embodiment, the spline elements (51, 58) are preformed in an axially asymmetric fashion along their lengths, creating a different geometry in their distal regions than in their proximal regions.
Abstract:
Electrode structures (20) are formed from flexible, porous, or woven materials. One such structure is made by forming first and second body sections (225), each including a peripheral edge. The first and second body sections (225) are joined together about their peripheral edges with a seam (224), thereby forming a composite structure. Another one of such structures is made by forming a body having a three-dimensional shape and opposite open ends, and at least partially closing at least one of the opposite ends by forming a seam. Another one of such structures is formed from a sheet of material having peripheral edges. The sheet is placed on the distal end of a fixture, while the peripheral edges of the sheet are gathered about the proximal end of a fixture, thereby imparting to the sheet a desired shape. At least one pleat is formed to secure the gathered peripheral edges together. The seams or pleats are formed by thermal bonding, or ultrasonic welding, or laser welding, or adhesive bonding, or sewing.
Abstract:
This invention is systems and methods to heat or ablate body or ablation energy to a tissue region. The systems and methods measure a first temperature using a temperature sensing element associated with the electrode (16). The systems and methods also measure a second temperature using a temperature sensing element associated with the electrode (16). The systems and methods process at least one of the first and second temperatures to derive a prediction of maximum temperature of the tissue region. The systems and methods generate an output that controls the transmission of the heating or ablation energy based, at least in part, upon the maximum tissue temperature prediction.
Abstract:
Systems and methods acquire electrocardiograms using a first electrode (24) associated with a region of heart tissue and a second body surface electrode. An analog or digital processing element (32) is coupled to the first and second electrodes for conditioning the first electrode to emit a pacing signal (48) and for conditioning the second electrode to sense paced electrocardiograms occurring as a result of the pacing signal. The systems and methods also employ a template of an electrocardiogram of a cardiac event of known diagnosis; for example an arrhythmia that the physician seeks to treat. The systems and methods compare this event-specific template to a sample of a paced electrocardiogram. The comparison yields a matching coefficient indicating how alike the input sample is to the input template. The matching coefficient can be used by the physician, for example to aid in the location of sites that are potentially appropriate for ablation (46).
Abstract:
This invention is systems and methods to examine heart tissue morphology using three or more spaced apart electrodes (38), at least two of which are located within the heart in contact with endocardial tissue. The systems and methods transmit electrical currents (64) through a region of heart tissue lying between selected pairs of the electrodes, at least one of the electrodes in each pair being located within the heart. The systems and methods derive the electrical characteristic of tissue lying between the electrode pairs based, at least in part, upon sensing tissue impedances. The systems and methods (206) also sense the timing of local depolarization events in the tissue in which impedance is sensed, and derive therefrom the propagation velocities of the sensed depolarization events.
Abstract:
An imaging element characterizes tissue morphology by analyzing perfusion patterns of a contrast media in tissue visualized by the imaging element, to identify infarcted tissue. In a preferred implementation, a catheter tube (12) introduced into a heart region carries the imaging element (34), as well as a support structure (20) spaced from the imaging element, which contracts endocardial tissues. The imaging element is moved as the imaging element visualizes tissue. A selected electrical event is sensed in surrounding myocardial tissue which regulates movement of the imaging element. The support element stabilizes the moving imaging element as it visualizes tissue, providing resistance to dislodgment or disorientation despite the presence of dynamic forces.
Abstract:
An electrode support structure comprises a distal hub (48) and a proximal base (12) aligned along a major axis with the distal hub (48). An array of generally flexible spline elements (180) extends between the hub (48) and the base (12). The spline elements (180) each have an elongated axis that, at the base (12), extends generally parallel to the major axis and, at the hub (48), extends at an angle measured relative to the major axis of between 45 degrees and 110 degrees. The spline elements (180) collectively define a distal surface (66) lying within an envelope that approximates the curvature of endocardial tissue and within which envelope the distal hub (48) lies. According to this aspect of the invention, the distal surface (66), when contacting endocardial tissue, increases in surface area in response to force applied generally along the major axis to mediate tissue pressure.