St Jude Medical, Atrial Fibrillation Division, Inc

Pacesetter, Inc.

Clinton W Schneider

Richard E Stehr

Thomas Flavian Strange

Todd Stangenes

R Jason Hemphill

Thomas V Graham

John P Gerhart

Katherine E Sudduth

Todd R Stangenes

Disclosed herein are various catheter and catheter systems that are useful in ablating tissue that is also subject to surface perfusion, for example blood flow across and/or through tissue. A representative embodiment of a catheter useful with the present invention includes an anemometer located on an exterior surface of the distal portion of the catheter. The anemometer is thermally isolated from the distal tip to permit the anemometer to measure the cooling effect of surface perfusion. The ablation catheter may include thermal insulation to insulate the anemometer from the distal tip. Alternatively, and/or in addition, the anemometer may be positioned proximally of the distal tip. The catheter may include one or more temperature sensors thermally coupled to the distal tip to measure the temperature of the distal tip. The distal tip may include one or more spiral grooves, or one or more holes. It is contemplated that the anemometer may be positioned within any such spiral groove or hole using a thermal insulation material, such as a non-conductive adhesive. The catheter may optionally include a contact sensor on the distal portion to assess a degree of contact between the ablation catheter and tissue being treated. Various ablation systems and methods are described herein that utilize catheters as described above.

Ablation devices, systems and method for measuring cooling effect of fluid flow

A compensation circuit has a predetermined, known complex impedance and is located in a handle of a catheter or in a distal end of a cable that connects to the catheter. The compensation circuit is probed with a pilot signal produced by a compensation control that is external to the catheter, by way of an electrical connection through the connecting cable. The compensation control measures the complex impedance, which is the combination of the circuit's known impedance as well as that of the cable. The compensation control then determines the difference between the measured and the known complex impedances. The difference represents that which is attributable to the cable, and is used to compensate or cancel out such cable-related contributions to complex impedance in measurements made over other electrical connections in the same cable. In another aspect, an unknown tissue is identified as one of a plurality of possible tissue types such as regular myocardium, scar and fat based on the measured phase angle of the complex impedance of the unknown tissue.

Method and apparatus for complex impedance compensation

The invention is directed to a catheter suitable for medical procedures such as cardiac ablation. The catheter includes a front-loaded catheter tip with an electrically active element. The catheter can include an elongate catheter shaft assembly having an inner shaft member with a distal end and a proximal end, and an outer shaft member with a distal end, a proximal end, and a lumen between the distal end and the proximal end. The inner shaft member can be inserted into the lumen of the outer shaft member along a longitudinal direction. The inner shaft member can include, at the distal end, a catheter tip member having a lateral dimension that is larger than a lateral dimension of the lumen of the outer shaft member. The catheter tip member includes at least one electrically active element, and the proximal end of the inner shaft member has at least one electrode disposed on the external surface of the shaft member, such that when inserted into a handle, the electrode electrically contacts an electrical connector element.

Catheter assembly with front-loaded tip and multi-contact connector

A method of producing an electrode for use in the manufacture of electrolytic capacitors for implantable cardioverter defibrillators comprises first coating the foil with a photoresist, second, applying a holographic image to the photoresist, third, removing a portion of the photoresist to expose a portion of the foil and create a pattern of photoresist on the foil and etching the foil. Alternatively, the method comprises applying an oxide or metal layer to the exposed foil surface, removing the pattern of photoresist to create a pattern of oxide or metal and etching the foil. The patterns of photoresist, oxide or metal all retard or prevent etching of the foil where the foil surface is covered. This results in a pattern of unetched foil with the remaining area being heavily etched. The resulting patterns stop crack propagation through the etched portions to yield foils with high gain and improved strength.

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Plymouth, MN, United States of America

Clinton W Schneider