Abstract: While a catheter that includes (i) a catheter body, and (ii) a catheter shaft, which includes a sensor and which is disposed inside a lumen of the catheter body, is inside a body of a subject, a coordinate system of the sensor is registered with a coordinate system of an imaging system, using (a) a calibration image, acquired by the imaging system, that shows an indication of a distal end of the catheter body, and (b) a signal from the sensor, but not using any indication of the sensor shown in the calibration image. Using the registering, a visual output is generated. Other embodiments are also described.

Abstract: A method for display, consisting of acquiring an electrical signal from a heart of a subject over multiple heart cycles. The electrical signal is partitioned into a succession of synchronized segments having respective start times at a selected annotation point in the heart cycles. The method includes overlaying respective graphical representations of the synchronized segments in the succession on a display screen, such that each segment is first presented on the display screen with an initial display intensity at a respective display time corresponding to a respective start time of the segment. The method further includes gradually decreasing a display intensity of each segment overlaid on the display screen as a decaying function of a time elapsed since the respective display time.

Abstract: A location pad includes a housing having a flat surface and multiple field generators. The multiple field generators are fixed to the housing and are configured to generate respective magnetic fields having respective axes that are perpendicular to the flat surface.

Abstract: Apparatus, including a camera which has an objective lens configured to focus light from an object, and an imaging array configured to receive the focused light and in response thereto, to output a signal representative of an image of the object. The apparatus further includes a multiplicity of illuminators arrayed around the objective lens and configured to illuminate the object, and a processor which is coupled to differentially adjust respective light intensities emitted by the illuminators responsively to the signal.

Abstract: A method, including advancing a guidewire having a first diameter through a patient lumen, the guidewire being tracked by an electromagnetic system and an impedance system. While advancing the guidewire, signals of both systems, that are generated in response to differing positions of the guidewire in the lumen, are recorded. The method includes recording correspondences between the signals at each of the differing positions. The method also includes withdrawing the guidewire from the lumen, and then advancing through the lumen a second guidewire, having a second diameter smaller than the first diameter, which is tracked by the impedance system. While advancing the second guidewire, a signal of the impedance system generated in response to advancement of the second guidewire in the lumen is received. The method includes applying the correspondences to the signal in order to determine a position of the second guidewire in the lumen.

Abstract: A guidewire, consisting of a hollow tube, containing a longitudinal lumen and having a spiral channel cut into the tube, and having a distal end. The guidewire has an elongate flexible core positioned within the longitudinal lumen. The guidewire also has a conductive coil, wound around the core at a location within the lumen in proximity to the distal end, that is coupled to output a signal in response to a magnetic field applied to the guidewire.

Abstract: An electrophysiologic catheter with an improved control handle is provided. The catheter includes a heat transfer assembly to better dissipate heat in the control handle. The heat transfer assembly includes a pump, a reservoir containing a coolant, a heat transfer member, and a coolant transport network transporting coolant between at least the reservoir and the heat transfer member. In one embodiment, the heat transfer member is located within the control handle as a heat exchanger on the circuit board to receive the coolant for transferring heat from the integrated circuits to the coolant. In another embodiment, the heat transfer member is located on the circuit board directly surrounding the integrated circuits to internally cool the integrated circuit within the control handle. A second heat transfer member is located outside of the control handle as a heat exchanger.

Abstract: Wall thickness of a cavity is determined by inserting a catheter into contact with a wall of a cavity in a body of a subject. The distal segment of the catheter is provided with a contact force sensor and an ultrasound transducer. The transducer is actuated to acquire ultrasound reflection data from the wall of the cavity, and while the transducer is actuated, the catheter is reciprocated against the wall of the cavity and the contact force measured between the catheter and the wall of the cavity. The reflection data is correlated with the contact force. A set of the correlated reflection data having the highest correlation with the contact force is identified. The tissue thickness between the inner surface and the identified set of the reflection data is calculated according to the time-of-flight therebetween.

Abstract: Methods and systems facilitate catheterization of a living subject by passing a fluid through an irrigation conduit. Heat energy is delivered to the conduit to create a heated pod of irrigation fluid that propagates downstream from the heat source. A departure time of the pod from a first location in the conduit is recorded, and an arrival time of the pod is detected at a second location that is downstream from the first location. A transit time of the pod from the first location to the second location is determined, and the flow of the fluid is adjusted responsively to the transit time.

Abstract: A method for display, consisting of acquiring an electrical signal from a heart of a subject over multiple heart cycles. The electrical signal is partitioned into a succession of synchronized segments having respective start times at a selected annotation point in the heart cycles. The method includes overlaying respective graphical representations of the synchronized segments in the succession on a display screen, such that each segment is first presented on the display screen with an initial display intensity at a respective display time corresponding to a respective start time of the segment. The method further includes gradually decreasing a display intensity of each segment overlaid on the display screen as a decaying function of a time elapsed since the respective display time.

Abstract: Tissue ablation systems and methods are provided, wherein a cardiac catheter incorporates a pressure detector for sensing a mechanical force against the distal tip when engaging an ablation site. Responsively to the pressure detector, a controller computes an ablation volume according to relationships between the contact pressure against the site, the power output of an ablator, and the energy application time. A monitor displays a map of the heart which includes a visual indication of the computed ablation volume. The monitor may dynamically display the progress of the ablation by varying the visual indication.

Abstract: A method for displaying information includes receiving a measurement with respect to an invasive probe inside a body of a subject of at least one probe parameter, selected from a group of parameters consisting of a bend angle of the probe and a pressure on the probe. Responsively to the measurement, an icon is displayed on a display screen representing the at least one probe parameter for viewing by an operator of the probe.

Abstract: A method, consisting of, while imaging a patient using an initial magnetic resonance imaging (MRI) sequence, receiving an initial set of electrocardiograph (ECG) signals from the patient. The method includes identifying initial noise in the initial set of ECG signals arising from the initial MRI sequence, and characterizing the initial noise in terms of frequency components thereof. The method further includes generating a relation between parameters defining the initial MRI sequence and the frequency components, computing a filter by applying the relation to the parameters of a subsequent MRI sequence, and applying the computed filter to reduce noise in a further set of ECG signals, received from the patient, while imaging the patient using the subsequent MRI sequence.

Abstract: A method for tracking a position of a sensor includes generating a periodic magnetic field in a vicinity of the sensor, the field having a positive polarity phase and a negative polarity phase with respective constant positive and negative amplitudes. First and second field measurement signals are produced responsively to the magnetic field at the sensor during the positive and negative polarity phases, respectively. The position of the sensor is determined responsively to the first and second field measurement signals.

Abstract: An electrophysiologic catheter with an improved control handle is provided. The catheter includes a heat transfer assembly to better dissipate heat in the control handle. The heat transfer assembly includes a pump, a reservoir containing a coolant, a heat transfer member, and a coolant transport network transporting coolant between at least the reservoir and the heat transfer member. In one embodiment, the heat transfer member is located within the control handle as a heat exchanger on the circuit board to receive the coolant for transferring heat from the integrated circuits to the coolant. In another embodiment, the heat transfer member is located on the circuit board directly surrounding the integrated circuits to internally cool the integrated circuit within the control handle. A second heat transfer member is located outside of the control handle as a heat exchanger.

Abstract: In techniques for testing and calibrating an ablator, a tissue probe emulator is connectable to a tissue ablator being tested. The emulator includes a temperature sensor, a thermoelectric unit operative to vary a temperature sensed by the temperature sensor, an adjustable electrical load, electrical control circuitry connected to the thermoelectric unit and the electrical load and operative to independently adjust the electrical load and an output of the thermoelectric unit. The emulator conveys signals emitted by the temperature sensor to the tissue ablator and conveys an ablation energy output of the tissue ablator to the electrical load.

Abstract: An apparatus, including a bus having electrical power and data lines, and a plurality of location pads, which are positionable at different, respective locations with respect to a body cavity in which the object is located, and which are connected to the bus in series so as to receive electrical power and exchange data signals over the bus. Each location pad includes multiple radiator coils and driving circuitry configured to select, responsively to the data signals, different respective driving frequencies for the coils and to generate, using the electrical power from the bus, driving signals to drive the coils to produce magnetic fields at the respective driving frequencies. The apparatus also includes a console, which is configured to receive and process sensor signals from a magnetic sensor fixed to the object, in response to the magnetic fields in the body cavity, in order to compute position coordinates of the object.

Abstract: A method includes disposing multiple medical probes to acquire physiological data concurrently from a living body. The data is sent from the multiple medical probes by transmitting over wireless channels respective sequences of data packets that are marked with respective packet numbers. A synchronization signal that is broadcast to the multiple probes is received in the probes. In response to receiving the synchronization signal, the packet numbers that are to be assigned in the probes to subsequent data packets in the respective sequences are reset.

Abstract: A method includes disposing multiple medical probes to acquire physiological data concurrently from a living body. The data is sent from the multiple medical probes by transmitting over wireless channels respective sequences of data packets that are marked with respective packet numbers. A synchronization signal that is broadcast to the multiple probes is received in the probes. In response to receiving the synchronization signal, the packet numbers that are to be assigned in the probes to subsequent data packets in the respective sequences are reset.

Abstract: A medical probe includes an elongate body for insertion into an organ of a patient, and an electrode that is attached to the elongate body. Multiple thermocouples are disposed at respective different locations of the electrode and electrically coupled to the electrode, and are configured to sense respective temperatures at the locations.