摘要:
A steerable catheter comprising a resilient deflectable body member having an expandable electrode array at the distal end thereof, and a manipulation handle attached to the proximal end of the body member, the handle including an array deployment device. A mandrel is movable through the shaft of the catheter by control movements at the handle to deploy the array or collapse the array as selected. A displacement compensation system is operatively connected to the mandrel such that when the array is expanded, the compensation system biases the mandrel so keep the array expanded, even during instances of deflection of the distal end. Similarly, the displacement compensation system biases the mandrel to keep the array collapsed when that configuration is selected, even during instances of straightening of the catheter. The displacement compensation system also compensates for overturning the control device in the handle to protect the array and deployment systems.
摘要:
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.
摘要:
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.
摘要:
A catheter has a stylet formed of a shape-retentive and resilient material having a preformed curved shape at its distal end resulting in the catheter sheath having the preformed curved shape. The catheter sheath has a plurality of electrodes at its distal end for contacting selected biological tissue for imparting ablation energy thereto. The catheter sheath also has an axially mounted tendon for causing deflection of the distal end. The stylet material permits straightening the catheter sheath during insertion into the patient and advancing the electrodes to the target tissue. Upon removal of the straightening forces, such as by entry into a chamber of the heart, the stylet material resumes its preformed curved distal shape thereby forcing the catheter distal end with the electrodes into the same preformed curved shape. The operator may place the curved distal end into contact with the target tissue and axially move the tendon as desired to gain greater control over the bend in the distal end of the catheter sheath to adjust the radius of curvature of the distal end to obtain greater contact of the electrodes with the heart tissue. Preferably, the stylet is formed of nitinol.
摘要:
A catheter having a preformed distal shape for positioning a plurality of electrodes at a selected biological site includes a sheath having a preformed bend in the distal end region to distribute axial forces applied, in the distal direction, to the distal end region over a surface area of the distal end region proximal the distal tip. Also included in the catheter sheath is a stylet formed of a material capable of retaining a shape with the distal end of the stylet shaped in the preformed bend. Preferably, the preformed bend is approximately 45 degrees. Axial forces applied to the catheter are deflected to cause bowing of the catheter so that a larger surface area of the catheter contacts the tissue, rather than the smaller surface area of the distal tip. In other aspects, the portion of the sheath coincident with the preformed bend has a lower durometer, the stylet is more flexible by having a reduced diameter and the electrodes are located proximal to the preformed bend.
摘要:
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.
摘要:
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.
摘要:
A method of assessing the adequacy of contact between an ablation electrode and biological tissue within a biological organ having biological fluid therein includes the steps of positioning the ablation electrode proximal the biological tissue; positioning a reference electrode a distance from the ablation electrode; measuring the impedance between the ablation electrode and the reference electrode at a first frequency and measuring the impedance between the ablation electrode and the reference electrode at a second frequency. The percentage difference between the first-frequency impedance and the second-frequency impedance provides an indication of the state of electrode/tissue contact. In general, a percentage difference of at least approximately 10% serves as an indication of substantially complete electrode/tissue contact. A percentage difference in the approximate range between 5% and 10% serves as an indication of partial electrode/tissue contact. A percentage difference less than approximately 5% serves as an indication of no electrode/tissue contact. Ratiometric measurements may also be used to assess the state of electrode/tissue contact.
摘要:
A catheter has a stylet formed of a shape-retentive and resilient material having a preformed curved shape at its distal end resulting in the catheter sheath having the preformed curved shape. The catheter sheath has a plurality of electrodes at its distal end for contacting selected biological tissue for imparting ablation energy thereto. The catheter sheath also has an axially mounted tendon for causing deflection of the distal end. The stylet material permits straightening the catheter sheath during insertion into the patient and advancing the electrodes to the target tissue. Upon removal of the straightening forces, such as by entry into a chamber of the heart, the stylet material resumes its preformed curved distal shape thereby forcing the catheter distal end with the electrodes into the same preformed curved shape. The operator may place the curved distal end into contact with the target tissue and axially move the tendon as desired to gain greater control over the bend in the distal end of the catheter sheath to adjust the radius of curvature of the distal end to obtain greater contact of the electrodes with the heart tissue. Preferably, the stylet is formed of nitinol.
摘要:
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.