Abstract: Ablation device including a probe structure 10 having a proximal end 12 and a distal end 14. Probe structure 10 includes a tubular first catheter 16, a tubular second catheter 18 surrounding the first catheter and a tubular guide catheter extending within the first catheter 16. The first catheter 16 carries a cylindrical ultrasonic transducer 20 adjacent its distal end. The transducer 20 is connected to a source of electrical excitation. The ultrasonic waves emitted by the transducer are directed at the heart wall tissue. Once the tissue reaches the target temperature, the electrical excitation is turned on and off to maintain the tissue at the target temperature. Alternatively, the transducer 20 is subjected to continuous excitation at one power level and upon the tissue reaching the target temperature, the power level of the continuous excitation is switched to a second lower power level.

Abstract: Apparatus for treating cardiac arrhythmias includes an ultrasonic ablation device incorporating an ultrasonic emitter (22, 400), means (10, 14, 402, 404) for positioning the ablation device outside of the heart but adjacent the epicardial surface of the heart, and means (26, 28, 30) for focusing the ultrasonic energy emitted by the emitter into an ablation region, so that the ablation region is disposed within the wall of the heart.

Abstract: Apparatus and methods for ablating tissue such as cardiac tissue. The apparatus includes a probe carrying a first ablation element 11 which may include an ultrasonic transducer and a balloon structure which directs the ultrasonic energy, and an additional ablation element 17 located distal to the first ablation element. The mode of operation of the additional ablation element 17 may be different from that of the first ablation element 20. Both ablation elements may be positioned by positioning the probe. The first ablation element may be arranged to form a loop-like lesion, whereas the additional ablation element may be arranged to form a spot-like lesion.

Abstract: An ultrasonic transducer of the type containing a cylindrical piezoelectric active element mounted on a supporting tube is provided with a backing component made of an electrically and thermally insulating material forming a sleeve which extends between the piezoelectric element and the supporting tube. An insulating material is selected for the backing component which includes a substantial amount of entrained air. Preferably, the backing component is made of expanded polytetrafluoroethylene (EPTFE).

Abstract: Apparatus and methods for ablating tissue surrounding a tubular anatomical structure such as the wall of a blood vessel or prostatic tissue surrounding the urethra. The apparatus includes an ultrasonic emitter such as a cylindrical emitter and an inflatable annular lens balloon surrounding the ultrasonic emitter. The lens balloon is inflated with a liquid having acoustic velocity different than that of the surrounding medium, so as to form an annular refracting surface. The acoustic energy from the emitter is focused into an annular focal region.

Abstract: An ablation device, including a catheter and an ablation element incorporating one or more balloons at the distal end of the catheter, has a continuous passageway extending through it from the proximal end of the catheter to the distal side of the expandable ablation element. The ablation device ablates tissue by subjecting it to ultrasound energy, cryogenic energy, chemical, laser beam, microwave, or radiation energy. A probe carrying electrodes is introduced through this passageway and deploys, under the influence of its own resilience, to a structure incorporating a loop which is automatically aligned with the axis of the expandable ablation device, so that minimal manipulation is required to place the probe. Pulmonary vein potential is monitored in real time via the electrodes. The probe may have an atraumatic tip with a ball formed at the leading edge. The atraumatic tip prevents any tissue damage such as perforation of heart wall.

Abstract: Ablation apparatus such as a catheter (10) carrying an ultrasonic ablation device (20) including an ablation transducer (42) and a balloon reflector structure (22, 24) for directing ultrasonic energy from the ablation transducer into a ring-like ablation region (A) is provided with an imaging ultrasonic transducer (86) mounted on an imaging probe (80) which may be inserted into or through a passageway (18, 65) extending through the catheter and into or through the ablation device to image the ablation region or neighboring regions. Alternatively, the imaging transducer (102, 202) may be mounted within the balloon reflector structure or distal to this structure.

Abstract: A cardiac ablation device, including a steerable catheter (10) and an expandable ablation element (18) incorporating one or more balloons (20, 22) at the distal end of the catheter, has a continuous passageway (28, 30) extending through it from the proximal end of the catheter to the distal side of the expandable ablation element. A probe (72) carrying electrodes is introduced through this passageway and deploys, under the influence of its own resilience, to a structure incorporating a loop (82) which is automatically aligned with the axis of the expandable ablation device, so that minimal manipulation is required to place the sensor probe.

Abstract: A collapsible ultrasonic reflector incorporates a gas-filled reflector balloon, a liquid-filled structural balloon an ultrasonic transducer disposed within the structural balloon. Acoustic energy emitted by the transducer is reflected by a highly reflective interface between the balloons. In a cardiac ablation procedure, the ultrasonic energy is focused into an annular focal region to ablate cardiac tissue extending in an annular path along the wall. Devices for stabilizing the balloon structure and for facilitating collapse and withdrawal of the balloon structure are also disclosed.

Abstract: A balloon catheter is provided with a sleeve and a flexible material where, upon inflation of the balloon, the sleeve is slid over a ball joint, preventing the flexible material and tube from moving through a range of motion in order to prevent the tube from kinking and misaligning.

Abstract: An ultrasonic transducer of the type containing a cylindrical piezoelectric active element mounted on a supporting tube is provided with a backing component made of an electrically and thermally insulating material forming a sleeve which extends between the piezoelectric element and the supporting tube. An insulating material is selected for the backing component which includes a substantial amount of entrained air. Preferably, the backing component is made of expanded polytetrafluoroethylene (EPTFE).

Abstract: A steerable catheter has a steering portion incorporating a spear cut junction of catheter material, thereby providing for a gradual change in flexibility in the steering portion. A guide tube and spring may be located inside a pull wire lumen of the catheter, with the spring distal to the guide tube so that the spring is disposed at least partially within steering section. A steering mechanism moves the pull wire linearly in order to steer the catheter.

Abstract: A steerable catheter has a steering portion incorporating a spear cut junction of catheter material, thereby providing for a gradual change in flexibility in the steering portion. A guide tube and spring may be located inside a pull wire lumen of the catheter, with the spring distal to the guide tube so that the spring is disposed at least partially within steering section. A steering mechanism moves the pull wire linearly in order to steer the catheter.

Abstract: Ultrasound energy originating from an emitter at a number of predetermined positions is sensed by a plurality of duplex transducers in a predefined arrangement. Each transducer produces a sensor signal representing ultrasound energy sensed by it, and the sensor signals of each transducer are stored in association with the predetermined position producing the sensor signal. Thereafter, an ablation pattern corresponding to a group of the predetermined positions may be generated by actuating each transducer with a time-reversed version of the sensor signals stored in association with the group of positions. By placing the transducers in a predetermined spatial relationship to the heart, the ablation pattern may be formed on the ostium of a pulmonary artery. Preferably the predetermined positions correspond to a grid of dots that may be used to approximate virtually any shape.

Abstract: A collapsible ultrasonic reflector incorporates a gas-filled reflector balloon, a liquid-filled structural balloon an ultrasonic transducer disposed within the structural balloon. Acoustic energy emitted by the transducer is reflected by a highly reflective interface between the balloons. In a cardiac ablation procedure, the ultrasonic energy is focused into an annular focal region to ablate cardiac tissue extending in an annular path along the wall. Devices for stabilizing the balloon structure and for facilitating collapse and withdrawal of the balloon structure are also disclosed.

Abstract: Apparatus for treating cardiac arrhythmias includes an ultrasonic ablation device incorporating an ultrasonic emitter (22, 400), means (10, 14, 402, 404) for positioning the ablation device outside of the heart but adjacent the epicardial surface of the heart, and means (26, 28, 30) for focusing the ultrasonic energy emitted by the emitter into an ablation region, so that the ablation region is disposed within the wall of the heart.

Abstract: In a cardiac ablation procedure, ultrasonic energy is emitted from an ultrasonic ablation device (28) and is focused on myocardial tissue (30) within the wall of the heart or within the wall of a blood vessel connected to the heart (10). Ultrasound attenuation of the cardiac tissue is selectively increased by introducing microbubbles into the circulatory system of the subject so that the microbubbles enter the coronary arteries and pass into the myocardial tissue.

Abstract: Apparatus and methods for ablating tissue surrounding a tubular anatomical structure such as the wall of a blood vessel or prostatic tissue surrounding the urethra. The apparatus includes an ultrasonic emitter such as a cylindrical emitter and an inflatable annular lens balloon surrounding the ultrasonic emitter. The lens balloon is inflated with a liquid having acoustic velocity different than that of the surrounding medium, so as to form an annular refracting surface. The acoustic energy from the emitter is focused into an annular focal region.

Abstract: A collapsible ultrasonic reflector incorporates a gas-filled reflector balloon, a liquid-filled structural balloon an ultrasonic transducer disposed within the structural balloon. Acoustic energy emitted by the transducer is reflected by a highly reflective interface between the balloons. In a cardiac ablation procedure, the ultrasonic energy is focused into an annular focal region to ablate cardiac tissue extending in an annular path along the wall. Devices for stabilizing the balloon structure and for facilitating collapse and withdrawal of the balloon structure are also disclosed.

Abstract: A balloon catheter is provided with engagement elements disposed within the balloon so that, upon inflation of the balloon, the engagement elements move in the proximal to distal direction of the catheter so as to abut one another and form a substantially rigid column to maintain alignment of the distal end of the balloon with the proximal end of the balloon and with the catheter.