Abstract: A method is provided for generating a three-dimensional reconstruction of a portion of a surface of an organ, and, in particular, a portion of the surface of a chamber of the heart. The reconstruction is generated from location data of a plurality of acquisition points on the organ surface. The method comprises computing a two-dimensional reference plane based on the location data. A function that describes the surface is computed, wherein each point on the surface may be described as a function of the reference plane. The function is then bounded to a constrained region. Tessellation of the function facilitates computer display of the reconstruction. If the location data is accompanied by physiologic property data characteristic of the tissue, the method may be used to generate a reconstruction of the tissue property as a function of the tissue geometry.

Abstract: An apparatus for measuring electrical signals emanating from a body of a patient, and, in particular, from the patient's heart, comprises a catheter having an electrode array, preferably on its distal end. The apparatus of the invention further comprises a first amplifier for measuring a voltage from a first electrode of the array, and a cascade of differential amplifiers, each of which measures a voltage difference between two successive electrodes in the array.

Abstract: A system for detecting electrode-tissue contact comprises a catheter having a location sensor and a distal tip electrode. The catheter preferably further comprises a reference electrode that is preferably protected from making contact with tissue. The system further comprises a signal generator to transmit test signals to the distal tip and reference electrodes. Tissue contact is detected by comparing the signals across the tip electrode to a return electrode versus the signal across the reference electrode to a return electrode. Ablation energy may be delivered to the distal tip electrode if contact of the electrode with tissue is detected.

Abstract: A method for vascular reconstruction comprises the steps of advancing a catheter having a position sensor into the vessel, acquiring position information from the sensor at a plurality of points in the vessel, calculating a center-line of the vessel based on said position information, and calculating the inner surface of the vessel. The method of the invention preferably further comprises displaying the vessel reconstruction. The invention is also directed to apparatus for reconstructing vessels which comprises a catheter having a position sensor contained therein, means for acquiring position information from said sensor at a plurality of points in said vessel, means for calculating a centerline of the vessel based on said position information, and means for calculating the inner surface of the vessel.

Abstract: A system for detecting electrode-tissue contact comprises a multi-electrode catheter having a location sensor and a plurality of contact electrodes. The catheter preferably further comprises a reference electrode that is preferably protected from making contact with tissue. The system further comprises a signal generator to transmit test signals to each of the contact electrodes and to the reference electrode. Tissue contact is detected by comparing the signals across the tip electrode to a return electrode versus the signal across the reference electrode to a return electrode. Ablation energy may be delivered to the contact electrodes if contact of the electrode with tissue is detected.

Abstract: A system for determining the position of a medical device having a sensor comprises a plurality of field radiators wherein each field radiator has a plurality of radiator elements. Each radiator element generates a magnetic field such that each magnetic field is distinct from one another due to the use of a different frequency through simultaneous energizing of the radiator elements. A signal processor is operatively connected to the field radiators and the sensor of the medical device for receiving a sensing signal from the sensor indicative of the magnetic field sensed at the sensor. Alternative field radiator arrangements are also provided in conjunction with a novel algorithm utilizing a global convergent technique.

Abstract: A condition, such as an electrical property, of a chamber of a heart is surveyed with a catheter having a condition sensor at its distal tip. A method for surveying the chamber includes the steps of acquiring a first image of the chamber containing topographical information, advancing the distal tip of the catheter into the chamber, acquiring a second image including a representation of the catheter distal tip in the chamber, displaying a superposition of the topographical information extracted from the first image with the second image to generate a displayed superimposed image, acquiring condition information at a point on the chamber displayed on the superimposed image on or near the topographical information, and acquiring condition information at one or more additional points sufficient in number and spacing to permit the generation of a survey map of the condition in the chamber.

Abstract: A method of diagnosing an abnormal condition in a biological structure, such as the heart, including the steps of measuring a physiological response at at least three sampled points on a surface of the biological structure, calculating a vector function related to the response, displaying a representation of the vector function, and inferring the abnormal condition from the representation. The present invention is particularly useful for diagnosing cardiac arrhythmias, in which case the physiological response is a voltage, from which is inferred a local activation time and the vector function is a gradient of the local activation time, specifically, a conduction velocity.

Abstract: This invention relates to a composition containing a hydrophobic solvent, a network polymer and a flow control agent which is useful in healing wounds. The composition of this invention may be applied directly to a wound to create a structured occlusive dressing. The dressings of this invention do not migrate, but maintain their integrity at skin temperature, and encourage the creation of a moist wound environment while protecting the wound in order to accelerate healing.

Abstract: An effective and convenient medicament delivery system comprising novel extrudable compositions. The preferred compositions of the invention contain a thermoplastic water-soluble polymer selected from the group consisting of hydroxypropyl cellulose and polyethylene oxide; a water-soluble polymer derived from acrylic acid; medicament; and plasticizer. The compositions provide an effective medicament delivery system and are especially suitable for use with adhesive bandages.

Abstract: A dental floss comprising a multifilament yarn having at least one coating applied thereon. The yarn comprising the floss is substantially untwisted and comprises entanglement nodes having a frequency of between about 0.5 and about 3.5 inches. The yarn has a basis weight between about 500 and about 1200 denier. The coating applied to the yarn comprises a water-insoluble binder. Optionally, the floss may be coated with a second coating material comprising a water soluble substance such as polyethylene glycol for delivery of additives or additional flavors. With little or no twist and an optimum degree of air-entanglement, the yarn is held together loosely enough to allow a significant amount of coating material to be impregnated between the filaments but tight enough to provide shred and fray resistance and still have supple feel.

Abstract: This invention relates to a composition containing a hydrophobic solvent, a network polymer and a flow control agent which is useful in healing wounds. The composition of this invention may be applied directly to a wound to create a structured occlusive dressing. The dressings of this invention do not migrate, but maintain their integrity at skin temperature, and encourage the creation of a moist wound environment while protecting the wound in order to accelerate healing.

Abstract: A novel process for the extraction of salt from seawater based on the unique solubility properties of nonionic surfactants and the relative phobia of inorganic salts to organic surfactants has been developed. Nonionic surfactant is first added to the seawater to form a homogenous mixture. Then the temperature of the mixture is adjusted to cause it to separate into aqueous salt-rich and relatively salt-free phases. The relatively salt-free phase is then caused to phase separate into a surfactant-rich phase and a relatively surfactant-free and relatively salt-free water phase by further temperature adjustment. Finally, these latter two phases are separated to recover salt-free water.