Abstract: An electrode support structure comprises a distal hub and a proximal base aligned along a major axis with the distal hub. An array of generally flexible spline elements extend between the hub and the base. The spline elements each have an elongated axis that, at the base, extends generally parallel to the major axis and, at the hub, extends at an angle, measured relative to the major axis, of between 45.degree. and 110.degree.. The spline elements collectively define a distal surface lying within an envelope that approximates the curvature of endocardial tissue and within which envelope the distal hub lies. According to this aspect of the invention, the distal surface, when contacting endocardial tissue, increases in surface area in response to force applied generally along the major axis to mediate tissue pressure.

Abstract: A catheter tube carries an imaging element for visualizing tissue. The catheter tube also carries a support structure, which extends beyond the imaging element for contacting surrounding tissue away from the imaging element. The support element stabilizes the imaging element, while the imaging element visualizes tissue in the interior body region. The support structure also carries a diagnostic or therapeutic component to contact surrounding tissue.

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 the 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: An ablation electrode carries a temperature sensing element for measuring the temperature of the tissue being ablated. A thermal insulating element associated with the sensing element blocks the transfer of heat energy from between the temperature sensing element and the body. The temperature sensing element therefore measures temperature without being affected by the surrounding thermal mass of the electrode.

Abstract: An electrode support structure has a slotted hub and an integral body with a mid-section and opposed pair of spline elements that extend from the mid-section. The mid-section is captured within the slot, securing the integral body to the hub with the opposed spline elements radiating free of the slot for carrying one or more electrodes.

Abstract: Collapsible electrode assemblies and associated methods employ an array of filaments assembled to form a mesh structure. The mesh structure is adapted to selectively assume an expanded geometry having a first maximum diameter and a collapsed geometry having a second maximum diameter less than the first maximum diameter. Preferably, at least one of the filaments includes an electrically conductive material adapted for coupling to a source of ablation energy for transmitting ablation energy.

Abstract: A catheter has an electrode tip assembly that is bendable at the selection of the user in two different directions. The electrode tip assembly assumes different asymmetric predetermined curve configurations when bent in the two directions and is manipulated by means of steering wires adjustably connected tangentially to the lateral edges of a rotatable cam located in the catheter handle.

Abstract: A collapsible electrode body is assembled to an end of a catheter tube. A generally rigid stem element having an exterior diameter is connected to the catheter tube. A flexible tube, which has an initial interior diameter smaller than the exterior diameter of the stem element, is deformed into a desired geometry for the electrode body, including a neck region with an enlarged interior diameter greater than the exterior diameter of the stem element. The neck region is slipped about the stem element. Heat is applied to shrink the neck region about the stem element and form a first interference fit junction therebetween. A sleeve is fitted about the first interference fit junction, and heat is applied to shrink the sleeve about the interference fit junction and form a second interference fit junction therebetween. Preferably, after the first interference fit junction is formed, additional heat is applied to thermally fuse the neck region to the stem region.

Abstract: A probe for cardiac diagnosis and/or treatment has a catheter tube. The distal end of the catheter tube carries first and second electrode elements. The probe includes a mechanism for steering the first electrode element relative to the second electrode element so that the user can move the first electrode element into and out of contact with endocardial tissue without disturbing the contact of the second electrode element with endocardial tissue, even through the two electrode elements are carried on a common catheter tube. The distal end can carry a three dimensional structure having an open interior area. One of electrode elements can be steered through the open interior area of the structure. Electrode elements on the exterior of the structure can be used for surface mapping, while the electrode element inside the structure is steered to ablate tissue.

Abstract: Electrode structures are formed from flexible, porous, or woven materials. One such structure is made by forming first and second body sections, each including a peripheral edge. The first and second body sections are joined together about their peripheral edges with a seam, 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: Systems and related methods guide a movable electrode within an array of multiple electrodes located within the body. The systems and methods employ the movable electrode or at least one of the multiple electrodes on the array to generate and then sense electrical or sonic energy in a predetermined fashion to generates an output that locates the movable electrode within the array.

Abstract: Improved folding electrode assemblies and associated methods employ a structure comprising a wall peripherally enclosing an interior. The structure is adapted to selectively assume a geometry that changes between an expanded geometry having a first maximum diameter and a collapsed geometry having a second maximum diameter less than the first maximum diameter. At least one folding region in the wall is adapted to fold upon itself along a predefined fold line as the structure geometry changes. The folding region is formed when a portion of the wall is coated with an electrically conductive material for the purpose of transmitting electrical ablating energy, while another portion of the wall is left free of the electrically conductive material. Alternatively, the folding region is formed by forming an array of apertures in the wall.

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 be processed.

Abstract: An antenna assembly has an energy propagating region that is encapsulated in a material having a high dielectric constant for minimizing the loss of energy while having a high thermal conductivity for dissipating conductive heat patterns about the energy propagating region.

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: Systems and methods for heating or ablating body tissue place in contact with tissue an electrode, which includes an exterior wall peripherally surrounding an interior area. A lumen conveys a medium containing ions into the interior area. At least a portion of the exterior wall of the electrode comprises a porous material sized to pass ions contained in the medium. The systems and methods transmit electrical ablation energy to the medium for ionic transport through the porous material to tissue. The systems and methods sense temperature proximal to where the electrode contacts tissue. The systems and methods control transmission of electrical ablation energy to the medium based, at least in part, upon the temperature sensed.

Abstract: Systems and methods sense electrical events about a selected annulus region of the heart to identify the location of an accessory pathway. The systems and methods establish a contact site between heart tissue along the selected annulus and a multi-electrode array having a generally circular shape that conforms to the circumferential geometry of the selected annulus region. The systems and methods maintain the site of contact between the electrode array and heart tissue, while conveying signals representing electrical events sensed by bipolar pairs of the electrodes in the selected annulus region, The systems and methods display the signals as graphic information that represents the time differences between the atrial and ventricular electrogram complexes sensed by bipolar pairs of the electrodes on the selected annulus region. The bipolar pair of electrodes displaying the least time separation between the atrial and ventricular complexes identifies the region of the accessory pathway.

Abstract: An electrode tip assembly for a catheter is bendable under the control of the user. The distal tip portion of the assembly is progressively less resistant to bending than the remaining portions. The variable stiffness is provided by tapering the width or thickness of a bendable spring component or otherwise providing a progressive change in bending characteristics by notching, dimpling or stepping the thickness of the spring.

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: Systems and methods achieve defibrillation of a heart tissue region without resort to drugs or a painful electrical shock. The systems and methods sense electrical activity in the heart tissue region and generate an organization-indicating output. The organization-indicating output varies in relation to organization of heart rhythm in the heart tissue region. Use of the organization-indicating output guides the physician in organizing and entraining the heart tissue region.