Abstract: Discloses herein are ablative catheters and methods of use. The catheters can include a cooling chamber for circulating cooling fluid within the catheter tip to reduce hot spots within the catheter tip and/or to reduce the formation of coagulum. A proximal cooling chamber can be positioned proximally to a thermal mass for cooling a proximal portion of the catheter. In addition, or alternatively, a distal cooling chamber can be positioned for cooling a distal portion of the catheter tip. The cooling fluid can flow the ablative catheter in an open, closed, or open and closed loop.

Abstract: Devices and systems for ultrasonically imaging tissue and performing ablation therapy are disclosed. An ablation probe for treating and imaging body tissue includes an ablation electrode tip with a number of acoustic openings and a plurality of ultrasonic imaging sensors disposed within an interior lumen of the tip. The ultrasonic imaging sensors are supported within the interior lumen via an insert equipped with a number of recesses that receive the ultrasonic imaging sensors. An acoustically transparent shell disposed between the ultrasonic imaging sensors and the acoustic openings forms a fluid channel in the acoustic pathway of the sensors. During an ablation procedure, cooling fluid from an external fluid source is delivered through the fluid channel, providing an acoustic coupling effect between the ultrasonic imaging sensors and the surrounding body tissue.

Abstract: Apparatus and methods for performing cryogenic ablation of tissue and adjusting the size and/or location of a cryogenic cooling region. A cooling assembly may include tubes for dispensing and exhausting a coolant or refrigerant. One or both of the tubes may be moved, e.g., slidably adjusted, in order to adjust the location or size of a cryogenic ablation region. The cooling assembly may be integrated into cryogenic ablation devices including a cryogenic balloon device that includes an inner inflatable balloon and another balloon that is at least partially wrapped around the inner balloon and carries refrigerant for performing cryo-ablation. Electrodes permit electrical mapping of tissue before or after cryo-ablation to verify success of the procedure.

Abstract: In some implementations, a method of ablating body tissue includes (a) locating an inflatable balloon portion of a cryotherapy balloon catheter at a treatment site internal to a patient's body, and inflating the inflatable balloon portion; (b) employing electrodes that are disposed on an expandable surface of the inflatable balloon portion to electrically characterize body tissue at the treatment site; (c) ablating the body tissue by supplying a cryotherapy agent to the inflatable balloon portion to cool the body tissue to a therapeutic temperature; (d) employing the electrodes to determine whether the ablating caused desired electrical changes in the body tissue; and (e) repeating (c) and (d) when it is determined that the ablating did not cause the desired electrical changes.

Abstract: An electrophysiology system comprises an ablation catheter, a radiofrequency generator, and a mapping processor. The ablation catheter has a tissue ablation electrode and a plurality of microelectrodes distributed about the circumference of the tissue ablation electrode and electrically isolated therefrom. The plurality of microelectrodes define a plurality of bipolar microelectrode pairs. The mapping processor is configured to acquire output signals from the bipolar microelectrode pairs, compare the output signals, and generate an output to a display providing a visual indication of a characteristic of the microelectrodes and the tissue ablation electrode relative to myocardial tissue to be mapped and/or ablated.

Abstract: Devices, systems, and methods for performing a mapping procedure on body tissue are disclosed. An example mapping device for mapping a tissue surface includes an elongate shaft and an electrode assembly. The electrode assembly includes a plurality of splines and a plurality of electrodes disposed on at least some of the splines. The electrode assembly is capable of moving between a collapsed configuration and an expanded configuration. In the expanded configuration, the electrode assembly may have a generally planar structure.

Abstract: Devices, systems, and methods for performing ablation therapy on body tissue are disclosed. An example ablation device for treating body tissue includes an ionically conductive balloon and a radio-frequency electrode that delivers RF energy into a distal section of the balloon. The balloon can have a composite structure with a non-conductive section and a conductive section. A method for fabricating a semi-permeable ablation balloon using ionizing radiation and an etching process is also disclosed.

Abstract: A mapping catheter includes an elongated body for inserting into patient vasculature. A distal end of the elongated body includes a distal portion that includes a plurality of electrodes, a proximal portion disposed proximal to the distal portion, and a reduced-dimension portion disposed between the proximal and distal portions. The distal end is formed, at least in part, from a memory shape material that bends into a preformed shape upon release from a confined space. The preformed shape includes a first loop formed, at least in part, by the distal portion. The first loop is transverse to a longitudinal axis of the proximal portion. The reduced-dimension portion is configured and arranged to bend such that the reduced-dimension section advances distally through the first loop when the first loop is held in a fixed position and a force is applied distally along the longitudinal axis of the proximal portion.

Abstract: Devices, systems, and methods for performing ablation therapy on body tissue are disclosed. An example ablation device for treating body tissue includes an ionically conductive balloon and a radio-frequency electrode that delivers RF energy into a distal section of the balloon. The balloon can have a composite structure with a non-conductive section and a conductive section. The ablation device can have a steering mechanism configured to deflect the balloon.

Abstract: A mapping catheter includes an elongated body for inserting into patient vasculature. A distal end of the elongated body includes a distal portion that includes a plurality of electrodes, a proximal portion disposed proximal to the distal portion, and a reduced-dimension portion disposed between the proximal and distal portions. The distal end is formed, at least in part, from a memory shape material that bends into a preformed shape upon release from a confined space. The preformed shape includes a first loop formed, at least in part, by the distal portion. The first loop is transverse to a longitudinal axis of the proximal portion. The reduced-dimension portion is configured and arranged to bend such that the reduced-dimension section advances distally through the first loop when the first loop is held in a fixed position and a force is applied distally along the longitudinal axis of the proximal portion.

Abstract: Devices, systems, and methods for performing ablation therapy on body tissue are disclosed. An example ablation device for treating body tissue includes an ionically conductive balloon and a radio-frequency electrode that delivers RF energy into a distal section of the balloon. The balloon is configured to transmit the RF energy in a direction distally towards a leading end of the ablation device. Multiple ablation electrodes on the device can be used for providing lesions of different size or shape.

Abstract: An embodiment of an open-irrigated catheter system comprises a tip section, a distal insert, and mapping electrodes. The tip section has an exterior wall that defines an open interior region within the tip section. The exterior wall includes mapping electrode openings and irrigation ports. The exterior wall is conductive for delivering radio frequency (RF) energy for an RF ablation procedure. The irrigation ports are in fluid communication with the open interior region to allow fluid to flow from the open interior region through the irrigation ports. The distal insert is positioned within the tip section to separate the open region into a distal fluid reservoir and a proximal fluid reservoir. The mapping electrodes are positioned in the mapping electrode openings in the tip section.

Abstract: A system for performing mapping and ablation functions includes a catheter sized and shaped for vascular access. The catheter includes an elongate body extending between a proximal end and a distal end. A tip section positioned at the distal end of the catheter body and includes a proximal portion and a distal portion. One or more electrode structures are formed on an exterior surface of the tip section. The one or more electrode structures each includes a mapping electrode at the distal portion of the tip section and a contact pad electrically coupled to the mapping electrode.

Abstract: Catheters, systems, and methods are provided for performing medical procedures, such as tissue ablation, adjacent the ostia of anatomical vessels, such as pulmonary veins. The catheter comprises an elongated flexible catheter body including a proximal shaft portion and a distal shaft portion, which has a proximal section pre-shaped to form a curve having an apex sized to be inserted into an anatomical vessel, such as a pulmonary vein, and a distal section configured to contact an ostium of the vessel when the curve apex is inserted within the vessel ostium. The catheter further comprises a steering mechanism configured for decreasing a radius of curvature of the curve.

Abstract: Catheters and methods are provided for performing medical procedures. The catheter comprises an elongated flexible integrated catheter body having proximal and distal shaft portions, a central support positioned inside the distal shaft and at least one operative element carried by the distal shaft portion. The distal shaft portion has a proximal section configured to be internally actuated to form a simple curve with an apex that can be inserted into the vessel ostium, an intermediate section pre-shaped to form a curve that bends opposite the simple curve, and a distal section configured to be placed into a non-radial relationship with the vessel ostium when the apex of the simple curve is inserted into the vessel ostium.

Abstract: Devices and systems for ultrasonically imaging anatomical structures and performing ablation therapy within the body are disclosed. A combined ablation and ultrasound imaging probe includes an ablation electrode tip including an ablation electrode configured for delivering ablation energy, and a number of ultrasonic imaging sensors configured for imaging the tissue surrounding the probe. The ultrasonic imaging sensors are supported within the interior of the tip via a tip insert, and deliver ultrasonic waves through acoustic openings formed through the tip. The tip insert separates an interior lumen within the tip into a proximal fluid chamber and a distal fluid chamber. During an ablation procedure, the ultrasonic imaging sensors can be tasked to generate a number of ultrasonic images that can be displayed on a user interface.

Abstract: A system for performing mapping and ablation functions includes a catheter sized and shaped for vascular access. The catheter includes an elongate body extending between a proximal end and a distal end and having at least one inner fluid lumen. The catheter further includes a tip section positioned proximate to the distal end of the body. The tip section includes a proximal portion and a distal portion. The distal portion can have a distal end that can be substantially planar. The system also includes one or more electrode structures exposed at the tip section such that the one or more electrode structures disposed proximate the substantially planar distal end of the tip section.

Abstract: Medical devices and methods for making and using medical devices are disclosed. An example medical device may include a catheter for use in cardiac mapping and/or ablation. The catheter may include an elongate catheter shaft having a distal ablation electrode region capable of ablating tissue. A plurality of micro-electrode assemblies may be coupled to the distal ablation electrode region. At least one of the micro-electrode assemblies may include an inner electrode and an outer electrode disposed at least partially around the inner electrode. At least one of the inner electrode and the outer electrode may comprise a sensor.

Abstract: Catheters and methods are provided for performing medical procedures, such as tissue ablation, adjacent the ostia of anatomical vessels, such as pulmonary veins. The catheter comprises an elongated flexible integrated catheter body having proximal and distal shaft portions and at least one operative element carried by the distal shaft portion. The distal shaft portion has a proximal section configured to be internally actuated (e.g., using a steering mechanism or pre-shaping the proximal section) to form a simple curve with an apex that can be inserted into the vessel ostium, an intermediate section pre-shaped to form a curve that bends opposite the simple curve, and a distal section configured to be placed into a non-radial relationship (tangential or oblique) with the vessel ostium when the apex of the simple curve is inserted into the vessel ostium.

Abstract: In some implementations, a method of ablating body tissue includes (a) locating an inflatable balloon portion of a cryotherapy balloon catheter at a treatment site internal to a patient's body, and inflating the inflatable balloon portion; (b) employing electrodes that are disposed on an expandable surface of the inflatable balloon portion to electrically characterize body tissue at the treatment site; (c) ablating the body tissue by supplying a cryotherapy agent to the inflatable balloon portion to cool the body tissue to a therapeutic temperature; (d) employing the electrodes to determine whether the ablating caused desired electrical changes in the body tissue; and (e) repeating (c) and (d) when it is determined that the ablating did not cause the desired electrical changes.