Abstract: Methods of manipulating a catheterization apparatus involve providing a catheter having a flexible shaft with a preformed curve on a distal end of the flexible shaft, one or more electrodes disposed along the distal end of the flexible shaft, and a shape deflection area defined as a region on the flexible shaft between the preformed curve and a generally straight proximal portion of the flexible shaft. A first steering mechanism is anchored at a distal portion of the preformed curve, and a second steering mechanism is anchored distal to the shape deflection area. The method also involves changing a curvature of the preformed curve in response to a proximally directed force applied to the first steering mechanism, and moving the distal end of the catheter relative to the proximal portion of the flexible shaft in response to a proximally directed force applied to the second steering mechanism.

Abstract: A cardiac ablation apparatus for producing a circumferential ablation that electrically isolates a heart chamber wall portion from vessel such as a pulmonary vein extending into said wall portion comprises (a) an elongate centering catheter having a distal end portion; (b) an expandable centering element connected to said centering catheter distal end portion and configured for positioning within said vessel when in a retracted configuration, and for securing said elongate centering catheter in a substantially axially aligned position with respect to said vessel when said centering element is in an expanded configuration; (c) an ablation catheter slidably connected to said centering catheter said ablation element having a distal end portion, and (d) an expandable ablation element connected to said ablation catheter distal end portion.

Abstract: A catheter employs a pre-formed distal end and a proximal deflection mechanism for steering the catheter. A shaped member extends from a shaped region of the catheter sheath to at least a portion of an anchor region. A steering ribbon extends from a proximal region of the sheath and passes within at least a portion of the anchor region. A distal end of the steering ribbon is joined with a proximal portion of the shaped member. At least one steering tendon is disposed within the sheath and has a first end attached at the anchor region and a second end located at the proximal region of the sheath. Movement of the steering tendon in a proximal direction causes the deflection region to deflect relative to the longitudinal axis of the catheter while the shape of shaped region of the sheath is substantially maintained.

Abstract: Methods of using a catheter involve providing a sheath comprising a proximal region, a deflection region, a distal-end region including a shapeable region, an anchor region defined between the deflection region and the shapeable region, and a longitudinal axis. The method also involves imparting a pre-established shape to the shapeable region. The method further involves applying axial force in a proximal direction at the anchor region so as to cause the deflection region to deflect relative to the longitudinal axis while the pre-established shape imparted to the shapeable region of the sheath is substantially maintained.

Abstract: A guiding catheter system employs a compliant shaft with an inflatable balloon affixed to a distal portion of the shaft. The inflatable balloon includes channels that allow some amount of blood to flow past the balloon when inflated in a blood vessel. One or more inflation lumens is in fluid contact with the balloon and allows inflating the balloon from a proximal end of the catheter. A series of perfusion orifices may be included on the shaft proximal to the balloon.

Abstract: A catheter system includes an outer catheter having a lumen and an inner catheter sized to fit within and slide through the lumen of the outer catheter. Both catheters may be introduced into an anatomical site through a single introduction path. At the distal-end region of each catheter is an electrode system. One electrode system is for mapping the site; the other is for ablating the site. The distal-end regions of one or both of the catheters may be linear shaped, circular shaped, or radially expandable. When the catheter system is deployed the electrode systems carried by the distal-end regions of the mapping catheter and the ablation catheter are movable relative to each other and tend to lie in planes substantially parallel to each other. Another catheter system includes two separate electrode systems on a single expandable member shaped so that both electrode systems come in contact with separate sites.

Abstract: An electrophysiology catheter includes a flexible shaft with one or more electrodes disposed at a distal end having a preformed curve. A first steering apparatus allows altering a curvature of the distal end and a second steering apparatus allows steering of the distal end without significantly altering the curvature of the distal end. The first and second steering apparatuses are used for maneuvering the catheter and providing positive contact between the distal end and the tissue targeted for treatment.

Abstract: The efficacy of a lesion produced between a pair of ablation electrodes is assessed by analyzing the time it takes for a pulse of energy to travel from one electrode to the other. During a first time period, a first pulse of energy is applied to a first electrode. The time it takes for the pulse to conduct through the tissue to a second electrode is determined. During a time period subsequent to the first time, a subsequent pulse of energy is applied to the first electrode and the time it takes for the subsequent pulse to conduct through the tissue to the second electrode is determined. Changes in the conduction times are monitored by calculating the difference between consecutive conduction times and comparing the difference to a preset value. If the difference is below the preset value the lesion is considered adequate.

Abstract: A catheter for applying ablation energy to biological tissue having biological fluid flowing thereby includes a shaft having a distal-end region defining a tissue-contacting surface and a fluid-contacting surface. A plurality of band electrodes are positioned at the distal-end region of the shaft. A thermally conductive and non-electrically conductive surface covering, covers a portion of each of the band electrodes substantially coincident with the fluid-contacting surface. Each band electrode thereby has at least one masked portion substantially coincident with the fluid-contacting surface and at least one non-masked portion substantially coincident with the tissue-contacting surface. Ablation energy is transferred through the non-masked portion of the electrode. One or more thermal sensors are located in the non-masked portion of each of the band electrodes.

Abstract: A cardiac ablation apparatus for producing a circumferential ablation that electrically isolates a heart chamber wall portion from vessel such as a pulmonary vein extending into a wall portion comprises (a) an elongate centering catheter having a distal end portion; (b) an expandable centering element connected to the centering catheter distal end portion and configured for positioning within the vessel when in a retracted configuration, and for securing the elongate centering catheter in a substantially axially aligned position with respect to the vessel when the centering element is in an expanded configuration; (c) an ablation catheter slidably connected to the centering catheter the ablation element having a distal end portion, and (d) an expandable ablation element connected to the ablation catheter distal end portion.

Abstract: A catheter handle includes a steering controller with a self-locking mechanism to be used in conjunction with a steerable catheter shaft. A compression spring portion of the self-locking mechanism is located between the steering controller and a handle shell and causes alternating protrusions and recesses on the steering controller and on the handle shell to engage, thus locking the steering controller into a fixed position with the handle shell. Through a single-handed operation, an operator enables steering controller rotation by applying a force to the steering controller, which disengages the steering controller from the handle shell. The operator then adjusts the profile of a distal-end region of the catheter by rotating the steering controller. When the desired profile of the distal-end region of the catheter has been obtained, the operator removes the force from the steering controller and the spring decompresses to reengage the steering controller with the handle shell.

Abstract: A peel-away sheath for a catheter includes at least one weakened area in a non-longitudinal pattern, such as a helical pattern, along the length of the sheath. One embodiment of a catheter sheath includes a tube having at least one pull wire integrally located within its wall. Another embodiment of a catheter sheath includes a tube having at least one integral lumen within its wall. The integral lumen may house a filling material. One embodiment of a catheter may include a first sheath which is positioned within a second sheath, with each of the first and second sheaths having at least one weakened area along its length. A reinforcing guide for a guide catheter includes a tube having a lumen with a diameter at least as large as the guide catheter diameter. The reinforcing guide includes a gap with a width which is less than the guide catheter diameter.

Abstract: A catheter includes a steering mechanism for manipulating the distal end of the catheter to obtain a plurality of deflection profiles, a torque transfer system to enhance torque transfer from the handle to the distal tip, and a support system to reduce undesirable deformation of the distal-end region during steering. The torque transfer system includes a flat ribbon within the relatively flexible distal-end region to enhance torque transfer through the distal-end region of the catheter. The support system includes a compression cage and longitudinal struts that are located within the distal-end region of the catheter. The support system can support axial loads and deflect laterally in the direction of the steering, thereby reducing the amount of stretching and compression of the catheter sheath within the deflecting region.

Abstract: A catheter employs a pre-formed distal end and a proximal deflection mechanism for steering the catheter. A shaped member extends from a shaped region of the catheter sheath to at least a portion of an anchor region. A steering ribbon extends from a proximal region of the sheath and passes within at least a portion of the anchor region. A distal end of the steering ribbon is joined with a proximal portion of the shaped member. At least one steering tendon is disposed within the sheath and has a first end attached at the anchor region and a second end located at the proximal region of the sheath. Movement of the steering tendon in a proximal direction causes the deflection region to deflect relative to the longitudinal axis of the catheter while the shape of shaped region of the sheath is substantially maintained.

Abstract: A tip electrode for an ablation catheter mounted at the distal tip of an elongated catheter body member has a distal-end region and a proximal-end region. A tip thermal sensor is located at or near the apex of the distal-end region and one or more side thermal sensors are located near the surface of the proximal-end region. The electrode is preferably an assembly formed from a hollow dome-shaped shell with a core disposed within the shell. The side thermal sensor wires are electrically connected inside the shell and the core has a longitudinal channel for the side thermal sensor wires welded to the shell. The shell also preferably has a pocket in the apex of the shell, and the end thermal sensor wires pass through the core to the apex of the shell. Spaces between the shell and the core can be filled with epoxy resin. Alternatively, the electrode is formed of a solid metal having a plurality of bores for positioning thermal sensors at the tip and near the surface of the electrode.

Abstract: A catheter includes a steering mechanism for manipulating the distal end of the catheter to obtain a plurality of deflection profiles, and a torque transfer system at the distal portion to enhance torque transfer from the handle to the distal tip. The steering mechanism includes two steering tendons. The steering tendons are attached to the distal-end region of the catheter. The steering tendons may be located approximately angularly aligned, thus causing the deflection profiles to be unidirectional. Alternatively, the steering tendons may be located angularly separated from each other, thus causing the deflection profiles to be bidirectional. In other aspects, the torque transfer system includes a flat ribbon within the relatively flexible distal-end region to enhance torque transfer through the distal-end region of the catheter.

Abstract: A catheter assembly employs an outer catheter with a pre-formed distal end and an open lumen. An inner catheter having an open lumen and a pre-formed distal end is movably disposed within the outer catheter. Relative rotation and extension of the inner and outer catheters provides the distal end of the catheter assembly with an adjustable range of two- and three-dimensional shapes. The inner catheter can include sections of varying stiffness, such that extension of the inner catheter within the outer catheter modifies the shape of the outer catheter's pre-formed distal end. The adjustable shaping of the catheter assembly's distal tip provides an improved system for locating and cannulating cardiac venous structures, particularly the coronary sinus via the right atrium.

Abstract: A wire housed within a sheath is formed of a shape-retentive and resilient material having a curved shape at its distal-end region resulting in the catheter sheath having the curved shape. The catheter sheath also has an axially oriented tendon for causing deflection of the distal-end region. A movable outer sleeve surrounds the sheath and conforms the portion of the wire positioned within the outer sleeve to the shape of the outer sleeve. Upon relative displacement of the sheath and the outer sleeve a portion of the sheath extends beyond the outer sleeve and resumes its preformed curved distal shape thereby forcing the catheter distal-end region into the same curved shape. The operator may adjust the relative positions of the sheath and outer sleeve to changes the shape of the distal-end region. The operator may also axially move the tendon to adjust the radius or curvature of the distal-end region.

Abstract: A catheter includes a steering mechanism for manipulating the distal end of the catheter to obtain a plurality of deflection profiles, a torque transfer system to enhance torque transfer from the handle to the distal tip, and a support system to reduce undesirable deformation of the distal-end region during steering. The torque transfer system includes a flat ribbon within the relatively flexible distal-end region to enhance torque transfer through the distal-end region of the catheter. The support system includes a compression cage and longitudinal struts that are located within the distal-end region of the catheter. The support system can support axial loads and deflect laterally in the direction of the steering, thereby reducing the amount of stretching and compression of the catheter sheath within the deflecting region.

Abstract: A surface covering including a primary layer of a porous polymer structure and a secondary surface covering one or both of a metallic element layer and a hydrophilic layer is positioned over the surface of an ablation electrode. The pores of the surface covering are sized such that blood platelets are prevented from contacting the surface of the electrode while physiological fluid is allowed to pass through and contact the electrode surface to hereby provide a conduction path for current from the electrodes. The surface covering may further include an electrically non-conductive and thermally conductive portion positioned over another portion of the electrode to prevent alternate or non-intended site ablations.