Abstract: Analog or digital systems or methods filter an artifact from a signal derived from a biological event comprising sample values arranged with respect to time. The systems and methods generate a variable expressing a template of the artifact and reduce the derived biological signal by the variable to derive a filtered derived biological signal. The systems and methods change the variable over time based upon the energy of the filtered derived biological signal to minimize the energy of the artifact remaining in the filtered derived biological signal over time. The systems and methods output the filtered derived biological signal. The systems and methods remove artifacts from signals derived from a biological event; for example, electrograms, electrocardiograms, electroencephalograms, electrogastrograms, electromyograms, and respiratory signals.

Abstract: A flexible bond is formed between the exterior sleeve of a catheter guide tube and the exterior sleeve of the steerable electrode tip of the catheter. The flexible bond holds the sleeves in fluid tight abutment during twisting of the guide tube and bending of the electrode tip.

Abstract: Systems and methods analyze biopotential morphologies in myocardial tissue by comparing a template of a cardiac event of known diagnosis to one or more samples of a paced cardiac event. The systems and methods generate an output based upon the comparison. The comparison yields an output, which indicates how alike the input sample is to the input template. The output can be used by the physician, for example, to aid in the location of sites that are potentially appropriate for ablation. The systems and methods employing different pacing and/or comparative techniques to provide multiple outputs. The pacing techniques that the systems and methods employ can comprise entrainment pacing or pace mapping. Various alternative comparison techniques include matched filtering, cross correlation, norm of the difference, and symmetry matching.

Abstract: Systems and methods provide non-linear, non-median filters for signals derived from biological events. The systems and methods select a set of n sample values arranged with respect to time from the derived biological signal input. The systems and methods arrange the n sample values of the set into ordered positions following a predetermined permutation. The systems and methods select one of the ordered positions, z, within the permutation, where z is an odd positive integer greater or equal to one but less than or equal to n. The systems and methods generate a processed output comprising the sample value occupying the ordered position, z, in the permutation.

Abstract: Analog or digital systems and methods filter an artifact from a composite signal, which comprises sample values arranged with respect to time. The systems and methods select sets of WL sample values in time-sequence along the composite signal and arrange the WL sample values of each set into ordered positions following a predetermined permutation. The systems and methods select one of the ordered positions, z, within each permutation. The systems and methods generate a filter output comprising the sample values occupying the ordered position, z, of each permutation in time-sequence with the composite signal. The systems and methods remove artifacts from signals derived from a biological event; for example, electrograms, electrocardiograms, electroencephalograms, electrogastrograms, electromyograms, and respiratory signals.

Abstract: Systems and methods evaluate electrical contact between the myocardium and one or more electrodes inside the heart. The systems and methods electrically sense electrical contact between the myocardium and electrodes and generate unitary contact-indicating outputs indicating the presence or absence of electrical contact between the myocardium and each particular electrode. The systems and methods also correlate the electrode-specific unitary outputs to generate a compound contact-indicating output. The compound output represents the aggregate of the electrical contact between the myocardium and multiple electrodes on a multiple electrode array.

Abstract: Systems and methods use an array of multiple electrodes supported for operative association with a region of heart tissue, in tandem with a roving second electrode supported for movement relative to the multiple electrode means for operative association with selected, different regions of endocardial tissue within the heart. An analog or digital processing element conditions one of the multiple electrodes and the roving electrode to emit a pacing signal while the other one of the multiple electrodes and the roving electrode records paced electrograms occurring as a result of the pacing signal. A processing element and method input a template of a cardiac event of known diagnosis sensed using the array of multiple electrodes. The processing element and method inputs a sample of a cardiac event acquired by pacing from at least one roving electrode and sensed with the array of multiple electrodes.

Abstract: Systems and associated methods form larger and deeper lesion patterns by shaping a support body with multiple electrodes in ways that increase the density of the electrodes per given tissue area. The support body can carry either elongated, continuous electrodes or arrays of non-contiguous, segmented electrodes.

Abstract: Systems and methods examine heart tissue morphology using a pair of electrodes, at least one of which is located in contact with heart tissue. The systems and methods transmit electrical current in a path through the contacted heart tissue between the pair of the electrodes to derive a tissue electrical characteristic based, at least in part, upon sensing the impedance of the tissue lying in the path. The system and methods also sense with at least one of the electrodes the timing of local depolarization events in the contacted heart tissue. The systems and methods make possible the use of multiple endocardial electrodes for taking multiple measurements of the electrical characteristics of heart tissue. Multiplexing can be used to facilitate data processing. The systems and methods also make possible the identification of regions of low relative electrical characteristics, indicative of infarcted tissue, without invasive surgical techniques.

Abstract: A method of ablating tissue in the heart to treat atrial fibrillation introduces into a selected atrium an energy emitting element. The method exposes the element to a region of the atrial wall and applies ablating energy to the element to thermally destroy tissue. The method forms a convoluted lesion pattern comprising elongated straight lesions and elongated curvilinear lesions. The lesion pattern directs electrical impulses within the atrial myocardium along a path that activates the atrial myocardium while interrupting reentry circuits that, if not interrupted, would cause fibrillation. The method emulates the surgical maze procedure, but lends itself to catheter-based procedures that do not require open heart surgical techniques. A composite structure for performing the method is formed using a template that displays in planar view a desired lesion pattern for the tissue. An array of spaced apart element is laid on the template.

Abstract: A catheter having a proximal portion and a distal portion terminating in a distal tip, is provided with a spring assembly contained within its distal tip portion for providing a bias against side to side deflection of said distal tip. The assembly preferably includes a central wire having a first diameter, which central wire extends from the proximal portion of the catheter to the distal portion, and a plurality of wires secured to the central wire adjacent the distal end thereof. Each of the wires is stranded together, preferably twisted helically, around the central wire and preferably has a second diameter substantially smaller than the first diameter. Alternatively, the stranded wires can be attached along and parallel to the larger diameter wire, and the latter wire is of a substantially greater length than the stranded wires.

Abstract: A method of bonding sections of a catheter body together in abutting relationship including the steps of providing a temperature resistant polymeric sleeve, which sleeve preferably has a spirally wound metallic wire imbedded between its inner and outer diameters. The sleeve is inserted into ends of tubing segments to be joined together to form a catheter body. Then heat is applied over the area including the sleeve to melt the tubing over the sleeve.

Abstract: Systems and methods form curvilinear lesions in tissue within the body. The systems and methods expose tissue to electrode arrays with intersecting energy emitting elements. The systems and methods apply ablating energy for emission by the elements to create intersecting curvilinear lesion patterns in the tissue.

Abstract: A cardiac diagnosis and treatment system comprises a support carrying at least two electrodes. A conductor is associated with the support for selectively directing electrical signals to and from each electrode. The conductor includes a first buss for delivering power from an external power source, a second buss for transmitting electrode signals to an external signal processor, and a third buss for receiving control signals from an external signal source to multiplex the electrode signals from the electrodes through the second buss. A conduction line conducts power, control signals, and electrode signals from the external sources to the conductor.

Abstract: Systems and methods examine heart tissue morphology for the purpose of locating a potential ablation site. 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 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. The systems and methods match the derived tissue electrical characteristics with the derived propagation velocities in spatial relation to the electrodes to characterize the morphology of the contacted heart tissue to identify a potential ablation site.

Abstract: A device for ablating tissue within the body has an element 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 of a non-energy emitting material is movable over the region to adjust the impedance of the region.

Abstract: A steering mechanism including a steering shaft coupled to a controller which includes a handle and apparatus for manipulating the distal end of the steering shaft. The steering shaft includes a flexible coiled spring having a lead spring fixed in position with respect to a distal end thereof in the distal end of the steering shaft. One or more steering wires is affixed at the distal ends thereof to the lead spring. The steering wires extend through the steering shaft to the controller, and the steering apparatus of the controller is used to place tension on one or both of the steering wires. The attachment of the distal ends of the steering wires to the lead spring may be opposite one another or may be offset for providing greater maneuverability.

Abstract: A catheter having an elongated polymeric body with hollow encircling ring electrodes thereon and a method of forming the same are provided by the invention. Ring electrodes are each connected to an external electrical circuit by wires extending through the lumen, the wires each passing through an aperture through a wall of the body and being connected to an interior surface of the ring electrode. The tubular body of the catheter is expanded into a tight interference fit with the interior surfaces of the ring electrodes by heating the body to a temperature approaching its glass transition temperature to permit relief of internal stresses.

Abstract: An electrode assembly for use in interventricular cardiac mapping includes one or more elongated splines each of which carries a plurality of spaced apart electrodes thereon. The body of each spline is formed of a plurality of alternating electrically conductive layers and the electrically non-conductive layers. A separate electrically conductive pathway 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 so that signals provided by each of the electrodes can he processed.

Abstract: A flexible electrode circuit laces through a slit sleeve to expose electrodes outside the sleeve while enclosing the rest of the circuit within the sleeve. A stiffener member extends through the sleeve to support the sleeve and the flexible electrode circuit. The stiffener member is preferably connected to and constrained at opposite ends by a hub and a base to urge the stiffener member, the sleeve, and the electrode circuit into a predetermined curvilinear contour.