Abstract: A method of analyzing cardiac functions in a subject using a processing system. The method includes causing one or more electrical signals to be applied to the subject using a first set of electrodes, the one or more electrical signals having a plurality of frequencies. The method includes determining an indication of electrical signals measured across a second set of electrodes applied to the subject in response to the applied one or more signals. Following this, and for a number of sequential time instances, the method includes determining from the indicating data and the one or more applied signals, an instantaneous impedance value at each of the plurality of frequencies, and determining, using the using instantaneous impedance values, an intracellular impedance parameter. The intracellular impedance parameter over at least one cardiac cycle is the used to determine one or more parameters relating to cardiac function.

Abstract: A rotational angioplasty device having a handle housing and an exchangeable drive shaft cartridge. The handle housing includes a rotatable prime mover carried by a prime mover carriage which is longitudinally movable with respect to the handle housing. The exchangeable drive shaft cartridge includes a tubular core element, a longitudinally extendible tube, a catheter and a rotatable drive shaft which, near its distal end, has an abrasive tissue removal implement. The cartridge is detachable from the handle housing, the longitudinally extendible tube is detachable from the prime mover carriage, and the drive shaft together with its tissue removal implement may be attached to and detached from the prime mover, thereby permitting the exchangeable drive shaft cartridge to be selectively attached to and detached from the handle housing.

Abstract: A method of manufacturing a rotational atherectomy drive shaft having an asymmetrical tissue removal section. One or more strands of wire are helically wound about an elongated mandrel having an enlarged diameter section with a predetermined shape, thereby forming an elongated, flexible drive shaft which has an enlarged diameter tissue removal section. A portion of the drive shaft, including the enlarged diameter tissue removal section, is placed into a first clamp and given a first heat treatment to give the wire turns of the enlarged diameter tissue removal section an initial set, thereby preserving the initial shape of the enlarged diameter tissue removal section of the drive shaft. The drive shaft is then removed from the first clamp and the mandrel is dissolved. The enlarged diameter section of the drive shaft is then deformed to an asymmetrical shape by placing a portion of the drive shaft, including the enlarged diameter tissue removal section, into a second clamp.

Abstract: A rotational atherectomy device having a flexible, elongated, rotatable drive shaft with an eccentric enlarged diameter section. At least part of the eccentric enlarged diameter section has a tissue removing surface. The eccentric enlarged diameter section of the drive shaft has a center of mass and/or geometric center spaced radially from the rotational axis of the drive shaft, facilitating the ability of the device to open the stenotic lesion to a diameter substantially larger than the outer diameter of the enlarged diameter section.

Abstract: An atherectomy device for removing tissue from an artery. The device includes a flexible, elongated drive shaft rotatable about a guide wire, the drive shaft having an enlarged diameter tissue removal section. The drive shaft and the enlarged diameter tissue removal section are comprised of helically wound wire. Wire turns of the proximal portion of the tissue removal section have diameters that gradually increase distally at a generally constant rate thereby forming generally the shape of a cone. Wire turns of the distal portion of the enlarged diameter tissue removal section have diameters that gradually decrease distally thereby forming a generally convex distal portion. At least part of the tissue removal section includes an external coating of an abrasive material to define an abrasive segment of the drive shaft.

Abstract: A method of forming an elongate, flexible drive shaft which has utility as a rotational atherectomy device. In accordance with this method, an inner helical coil having a lumen and a proximal end is formed by winding a plurality of wires about a forming mandrel. An outer helical coil having a lumen and a proximal end is formed by winding a single wire with a mandrel-less coil forming machine. The inner helical coil is positioned within the outer helical coil to define a drive shaft. The inner and outer helical coils are oriented such that the inner helical coil is wound in a direction opposite that in which the outer helical coil is wound.

Abstract: A method of manufacturing a rotational atherectomy drive shaft having an asymmetrical tissue removal section. One or more strands of wire are helically wound about an elongated mandrel having an enlarged diameter section with a predetermined shape, thereby forming an elongated, flexible drive shaft which has an enlarged diameter tissue removal section. A portion of the drive shaft, including the enlarged diameter tissue removal section, is placed into a first clamp and given a first heat treatment to give the wire turns of the enlarged diameter tissue removal section an initial set, thereby preserving the initial shape of the enlarged diameter tissue removal section of the drive shaft. The drive shaft is then removed from the first clamp and the mandrel is dissolved. The enlarged diameter section of the drive shaft is then deformed to an asymmetrical shape by placing a portion of the drive shaft, including the enlarged diameter tissue removal section, into a second clamp.

Abstract: A rotatable atherectomy device having an exchangeable drive shaft cartridge and a rotatable prime mover coupling. The cartridge has a rotatable drive shaft socket carried by a carriage. The coupling radially expands during rotation such that it interlocks with the socket to drive a tissue removal implement on the end of a drive shaft attached to the cartridge. Upon slow or no rotation of the socket, the coupling disengages from the socket to allow for exchange of the cartridge.

Abstract: A rotational atherectomy device having a handle housing and an exchangeable drive shaft cartridge. The handle housing includes a rotatable prime mover carried by a prime mover carriage which is longitudinally movable with respect to the handle housing. The exchangeable drive shaft cartridge includes a cartridge housing, a longitudinally extendable tube, a catheter and a rotatable drive shaft which, near its distal end, has an abrasive tissue removal implement. The cartridge housing may be attached to and detached from the handle housing, the longitudinally extendable tube may be attached to and detached from the prime mover carriage, and the drive shaft together with its tissue removal implement may be attached to and detached from the prime mover, thereby permitting the exchangeable drive shaft cartridge to be selectively attached to and detached from the handle housing.

Abstract: A rotational atherectomy device having an improved optical tachometer which uses a single, monofilament optical fiber to both transmit light from a light source to a light reflector and to return reflected light to a light detector. A fiber optic connector which can be used with such a rotational atherectomy device permits one to releasably optically couple a distal end of an optical fiber to both a light source and a light detector via a beam splitter and a flexible light guide. This fiber optic connector may include a pneumatic clamp which is connected to the same source of compressed gas which drives the prime mover of the rotational atherectomy device.

Abstract: A rotatable intravascular apparatus having a flexible, elongated medical device and a mechanism for controlling the rotational orientation of the distal end of the medical device. The apparatus includes a flexible torquing sheath extending along a substantial length of the elongated medical device. The distal end of the torquing sheath is secured to the distal portion of the medical device, but not to the intermediate or proximal portions of the medical device, so that rotation of the proximal end of the torquing sheath with respect to the proximal portion of the medical device conveys torque to the distal end of the torquing sheath and, therefore, to the distal portion of the medical device, thereby rotating the distal portion of the medical device.

Abstract: A rotational atherectomy device which includes a handle housing and an exchangeable drive shaft cartridge removably attachable to the handle housing. A rotatable prime mover is carried by a prime mover carriage disposed within the handle housing, the prime mover carriage being longitudinally movable with respect to the handle housing. The exchangeable cartridge includes a cartridge housing which is removably attachable to the handle housing, a longitudinally movable tube which is removably attachable to the prime mover carriage, and a rotatable flexible drive shaft which is removably attachable to the prime mover. The rotational atherectomy device includes a cartridge latch, which removably locks the cartridge housing to the handle housing, and a tube latch which selectively locks the longitudinally movable tube against longitudinal movement with respect to the cartridge housing.

Abstract: A blower pressure source has been integrated into a vest cardiopulmonary resuscitation (CPR) system. The vest includes a bladder that cyclically inflates and deflates to provide automatic CPR to a patient in cardiac arrest or needing circulatory assistance to a patient with a beating but weakened heart. The blower continuously provides air at relatively low pressure to inflate a bladder in the vest. The maximum pressure of the blower corresponds to the desired peak vest pressure. A relatively simple valve, solenoid and timing controller is used to apply the blower air in cycles to inflate the bladder.

Abstract: An atherectomy device for removing tissue from an artery. The device includes a flexible, elongated drive shaft rotatable about a guide wire, the drive shaft having an enlarged diameter tissue removal section. The drive shaft and the enlarged diameter tissue removal section are comprised of helically wound wire. Wire turns of the proximal portion of the tissue removal section have diameters that gradually increase distally at a generally constant rate thereby forming generally the shape of a cone. Wire turns of the distal portion of the enlarged diameter tissue removal section have diameters that gradually decrease distally thereby forming a generally convex distal portion. At least part of the tissue removal section includes an external coating of an abrasive material to define an abrasive segment of the drive shaft.

Abstract: The invention provides a handle for a rotational atherectomy device, the handle including a guide wire clamp and a turbine brake operatively interconnected with the guide wire clamp so that the brake automatically prevents rotation of the turbine when the guide wire is unclamped. The brake is movable from a brake-released position to a brake-engaged position, in which position the brake prevents rotation of the turbine. A manual override is also provided, permitting unclamping of the guide wire independent of the position of the brake.

Abstract: An atherectomy device having a handle housing, a rotatable prime mover movable longitudinally with respect to the handle housing, a rotatable drive shaft having a proximal end connected to the prime mover for rotation and longitudinal movement therewith, and a distal end portion having a tissue removal implement usable to remove tissue from a bodily passageway. A guide wire clamp is disposed within the handle housing for releasably clamping the proximal portion of a guide wire. An override clamp is removably securable to the handle housing for moving the guide wire clamp to a guide wire-released position and for holding the guide wire clamp in such released position. The override clamp may also include a mechanical linkage to the prime mover so that the override clamp locks the prime mover in a particular longitudinal position with respect to the handle housing.

Abstract: A blower pressure source has been integrated into a vest cardiopulmonary resuscitation (CPR) system. The vest includes a bladder that cyclically inflates and deflates to provide automatic CPR to a patient in cardiac arrest or needing circulatory assistance to a patient with a beating but weakened heart. The blower continuously provides air at relatively low pressure to inflate a bladder in the vest. The maximum pressure of the blower corresponds to the desired peak vest pressure. A relatively simple valve, solenoid and timing controller is used to apply the blower air in cycles to inflate the bladder.

Abstract: A rotational atherectomy device having directional control for selectively removing tissue from an artery (or other bodily passageway or cavity). The atherectomy device includes a rotational atherectomy apparatus having a flexible, elongated drive shaft disposed in the lumen of a catheter. A central portion of an intermediate segment of the drive shaft is coated with an abrasive material to define an abrasive segment of the drive shaft. The drive shaft has a central lumen for receipt of a guide wire therein, and around which the drive shaft may be rotated. The guide wire has an intermediate portion with a predetermined curved positioning portion such that when the abrasive segment of the drive shaft is located along the curved positioning portion of the guide wire, such curved positioning portion of the guide wire urges the abrasive segment of the drive shaft laterally.

Abstract: A method and apparatus for in vivo removal of calcified deposits from an aortic valve. The apparatus includes an anchoring balloon catheter fixatable across the aortic valve, a tool for removing the deposits, and a mechanism means for securing the tool with respect to the anchoring balloon and the aortic valve. The method involves advancing an anchoring balloon catheter through the aorta and positioning it across the aortic valve, inflating the anchoring balloon to fixate it with respect to the aorta and aortic valve, and then operating a deposit removal tool secured to the anchoring balloon to remove the deposits.