Abstract: A locating system for determining the location and orientation of an invasive medical instrument, for example a catheter (10) or endoscope, relative to a reference frame, comprising: a plurality of field generators (18, 20, 22) which generate known, distinguishable fields, preferably continuous AC magnetic fields, in response to drive signals; a plurality of sensors (30, 32, 34) situated in the invasive medical instrument (10) proximate the distal end thereof which generate sensor signals in response to said fields; and a signal processor (26) which has an input for a plurality of signals corresponding to said drive signals and said sensor signals and which produces the three location coordinates and three orientation coordinates of a point on the invasive medical instrument.

Abstract: An elongate probe apparatus (20) for insertion into the body of a subject, comprising: a structure (24) having a substantially rigid configuration, a plurality of physiological sensors (26, 28, 30), which generate signals responsive to a physiological activity, said sensors (24, 28, 30) having substantially fixed positions on said structure (24) in said configuration; and one or more devices that generate position signals indicative of the positions of the physiological sensors on said structure in said configuration.

Abstract: A method of modifying the force of contraction of at least a portion of a heart chamber, including providing a subject having a heart, comprising at least a portion having an activation, and applying a non-excitatory electric field having a given duration, at a delay after the activation, to the portion, which causes the force of contraction to be increased by at least 5%.

Abstract: A method of measuring the size of an area (22) within a body, including bringing at least one position sensor (28) to each of a plurality of points in the area, determining position coordinates of the plurality of points, using the sensor (28) and calculating distances between the plurality of points.

Abstract: A method for mapping a heart comprises the steps of inserting a mapping catheter having an ultrasonic position sensor into the heart. At least one reference catheter having an ultrasonic position sensor is also inserted into the heart. The position of the mapping catheter is determined relative to the at least one reference catheter and a portion of the heart is mapped with the mapping catheter. Additionally, the at least one reference catheter may be provided outside of the heart.

Abstract: A system for mapping a heart comprises a mapping catheter having an ultrasonic position sensor for insertion into the heart. The system also comprises at least one reference catheter having an ultrasonic position sensor placeable in a fixed position relative to the heart. The position of the mapping catheter is determined relative to the at least one reference catheter. The ultrasonic position sensor of the mapping catheter is located at the tip of the mapping catheter. The ultrasonic position sensor for the at least one reference catheter is located at the tip of the at least one reference catheter.

Abstract: A method of modifying the force of contraction of at least a portion of a heart chamber, including providing a subject having a heart, comprising at least a portion having an activation, and applying a non-excitatory electric field having a given duration, at a delay after the activation, to the portion, which causes the force of contraction to be increased by at least 5%.

Abstract: Apparatus for intracardiac drug administration, including a catheter which is inserted into a chamber of the heart and brought into engagement with a site in the heart wall. The catheter includes at least one position sensor, which generates signals responsive to the position of the catheter within the heart, and a drug delivery device, which administers a desired dose of a therapeutic drug at the site determined responsive to the signals from the position sensor.

Abstract: A method of modifying the force of contraction of at least a portion of a heart chamber, including providing a subject having a heart, comprising at least a portion having an activation, and applying a non-excitatory electric field having a given duration, at a delay after the activation, to the portion, which causes the force of contraction to be increased by at least 5%.

Abstract: Apparatus for X-ray guided surgery, including a reference element (20), which is placed in contact with the body (32) of a subject. The element includes a plurality of fiducial marks (22a, 22b, 22c) and a first coordinate sensing device (24), in predetermined, fixed positions in the element (20). A surgical tool (36), having a distal end for insertion into the body (32), includes a second coordinate sensing device (40) fixed thereto. A fluoroscope (54) forms an X-ray image of the body, including the fiducial marks. A computer analyzes the image to determine the position of the reference element in the image, so as to find coordinates of the first coordinate sensing device relative to the image, and registers the position of the tool with the X-ray image by referring coordinates of the second coordinate sensing device to the known coordinates of the first position sensor.

Abstract: A method of excavating tissue in the body, including bringing a catheter (60) to a location, injecting microbubbles (84) at the location and causing cavitation of tissue (76) at the location using ultrasound. Preferably, the microbubbles (84) are injected directly into the tissue, such as by using a hollow needle (62). Alternatively, microbubbles (84) are injected into the vascular bed of the tissue at the location, so that the capillaries (86) are infused with microbubbles (84).

Abstract: A method of modifying the force of contraction of at least a portion of a heart chamber, including providing a subject having a heart, comprising at least a portion having an activation, and applying a non-excitatory electric field having a given duration, at a delay after the activation, to the portion, which causes the force of contraction to be increased by at least 5%.

Abstract: Apparatus for X-ray guided surgery, including a reference element (20), which is placed in contact with the body (32) of a subject. The element includes a plurality of fiducial marks (22a, 22b, 22c) and a first coordinate sensing device (24), in predetermined, fixed positions in the element (20). A surgical tool (36), having a distal end for insertion into the body (32), includes a second coordinate sensing device (40) fixed thereto. A fluoroscope (54) forms an X-ray image of the body, including the fiducial marks. A computer analyzes the image to determine the position of the reference element in the image, so as to find coordinates of the first coordinate sensing device relative to the image, and registers the position of the tool with the X-ray image by referring coordinates of the second coordinate sensing device to the known coordinates of the first position sensor.

Abstract: Apparatus for intracardiac drug administration, including a catheter which is inserted into a chamber of the heart and brought into engagement with a site in the heart wall. The catheter includes at least one position sensor, which generates signals responsive to the position of the catheter within the heart, and a drug delivery device, which administers a desired dose of a therapeutic drug at the site determined responsive to the signals from the position sensor.

Abstract: A method and apparatus for controlling activity of a heart of a living person during a medical procedure. Electrical signals are applied to the heart so as to induce a spontaneously-reversible cardioplegia thereof. The signals are preferably such that terminating application of the signals does not induce fibrillation. Most preferably, the signals have an amplitude that is below a level that would induce fibrillation upon termination thereof.

Abstract: This invention is an apparatus for modifying cardiac output of the heart of a subject, including one or more sensors which sense signals responsive to cardiac activity, and a stimulation probe including one or more stimulation electrodes which apply non-excitatory stimulation pulses to a cardiac muscle segment. Signal generation circuitry is coupled to the one or more sensors and the stimulation probe, which circuitry receives the signals from the one or more sensors and generates the non-excitatory stimulation pulses responsive to the signals.

Abstract: A method and apparatus for controlling a segment of excitable tissue, typically tissue of a heart, the segment having an intrinsic activity level. During a high phase, electrical energy of a given amplitude is applied to the segment. During a low phase, the amplitude of the electrical energy applied to the segment is reduced relative to that applied during the high phase, so that the segment's activity level increases during the low phase above the intrinsic activity level.

Abstract: A method of constructing a cardiac map of a heart having a heart cycle including; bringing an invasive probe into contact with a location on a wall of the heart; determining, at at least two different phases of the heart cycle, a position of the invasive probe; and determining a local non-electrical physiological value at the location. The method is repeated for a plurality of locations in the heart The positions are combined to form a time-dependent map of at least a portion of the heart and local relationships between changes in positions of the invasive probe and determined local non-electrical physiological values are determined. Preferably, local electrical activity at the plurality of locations is also acquired.

Abstract: A probe (20) for insertion into the body of a subject, the probe (20) having distal (22) and proximal ends, and including an electronic microcircuit (90), which stores information relating to calibration of the probe (20). Preferably, the microcircuit (90) stores a calibration code, which is encrypted. Alternatively or additionally, the microcircuit (90) stores a usage code, which controls availability of the probe (20) to a user thereof. Preferably, the probe (20) includes access control circuitry (90) that allows the usage code to be changed so as to reduce the availability of the probe (20), but not to increase the availability thereof.

Abstract: An apparatus for intracardiac drug administration of a therapeutic drug comprises a catheter having a distal end and a drug delivery device which is driveable from the distal end. The drug delivery device includes a needle and a spring-loaded mechanism operatively connected to the needle. The spring-loaded mechanism drives the needle out of the distal end of the catheter upon administering of the therapeutic drug. The spring-loaded mechanism returns the needle within the distal end of the catheter after the administering of the therapeutic drug.