Abstract: A system includes a balloon catheter having a shaft, an inflatable balloon fitted at a distal end of the shaft, and multiple electrodes disposed on the inflatable balloon, a display, and a processor configured to receive signals that are indicative of respective electrode positions of the multiple electrodes in 3D space, compute the respective electrode positions of the multiple electrodes based on the received signals, from among a plurality of virtual planes defined by different respective groups of the electrode positions, select a virtual plane that contains a maximum number of the electrode positions to within a given tolerance, fit a virtual circle to the electrode positions that are within the given tolerance of the selected virtual plane, and render to the display a 3D representation of the balloon catheter based on a position and orientation of the fitted virtual circle in 3D space.

Abstract: Cardiac catheterization is carried out by inserting a multi-electrode probe into a heart, constructing a position map of the electrodes, and simulating a 3-dimensional surface of the heart. The method is further carried out by placing the position map in registration with an acquired image of the heart, constructing, based on the position map, a mesh that models the 3-dimensional surface of the heart, and adjusting positions of vertices of the mesh relative to mapped points in the position map to improve a registration of the mesh with the acquired image.

Abstract: Described embodiments include a method that includes constructing a computerized electroanatomical model of a portion of a heart, the model including a mesh, which approximates the portion of the heart, and a plurality of points, at different respective locations on the mesh, having respective associated local activation times (LATs) that were ascertained from electrocardiographic signals acquired from the portion. The method further includes constructing a graph that interconnects the points and, based on the respective locations and LATs of the points, identifying, from a plurality of pathways, through the graph, from a first one of the points having a lowest one of the LATs to a second one of the points having a highest one of the LATs, both a shortest pathway and a longest pathway. The method further includes displaying the mesh, with the identified shortest pathway and longest pathway superimposed over the mesh. Other embodiments are also described.

Abstract: A method, consisting of presenting on a display screen a graphical image of a heart of a patient, including icons representing a catheter that is positioned within the heart and an electrode on the catheter, while the electrode is in contact with tissue at a location in the heart. The method further includes acquiring, using the electrode, electrical signals from the tissue at the location, and processing the acquired signals so as to detect an occurrence of a predefined signal feature in the acquired signals. The method also includes, upon detecting the occurrence of the predefined signal feature, modifying a visual feature of at least one of the icon representing the electrode and the icon representing the catheter on the display screen.

Abstract: A plurality of coordinates are mapped to respective first voxels. Each first voxel is assigned a value f(0), f(n) being a monotonic function defined between 0 and M inclusive. A plurality of second voxels {vi}, each of which is at a distance 1?d(vi)?M voxels from a nearest first voxel, are assigned respective second values {f(d(vi))}. Each of at least some of the second voxels is then iteratively assigned a weighted average of respective values of its immediate neighbors, any value differing from f(M) by not more than a first threshold being given a higher weight than any other value. A subset of the second voxels, each of which has a value differing from f(M) by more than a second threshold, are identified. Subsequently, a mesh representing a surface of a volume including the first voxels and the subset of the second voxels is generated.

Abstract: Apparatus, consisting of a catheter that is configured to be inserted into a chamber of a heart and that has one or more electrodes configured to contact myocardial tissue at multiple locations in the chamber. The one or more electrodes receive electrical signals responsive to a conduction wave traveling through the tissue. The apparatus includes a display and a processor that is configured to receive the electrical signals from the catheter and to render to the display, responsively to the electrical signals, a map of the chamber including an indication of local times of occurrence of the conduction wave at the multiple locations. The processor is also configured to calculate, responsively to the local times of occurrence, a velocity of the conduction wave between the locations and to mark on the map one or more areas of the chamber in which the velocity is below a preset threshold.

Abstract: Apparatus, consisting of an envelope transparent to X-rays, and a fluid transparent to X-rays and contained within the envelope. Multiple charged particles, opaque to X-rays, are suspended within the fluid. There are at least two electrodes on opposite sides of the envelope, that are configured to apply a field to the multiple particles, so that, absent the field, the particles disperse throughout the fluid.

Abstract: Described embodiments include an apparatus that includes a display, including a screen, and a processor. The processor is configured to define a bounding region on the screen. The processor is further configured to render a quadric, which is defined in a parameter space, over a three-dimensional electroanatomical map of a surface of a heart that is displayed on the screen, by, for each pixel in the bounding region, transforming, to the parameter space, a virtual ray that passes through the pixel, and ascertaining whether a point of intersection between the transformed virtual ray and the quadric exists in the parameter space, and, for each pixel in the bounding region for which the point of intersection exists, rendering the pixel on the screen, based on properties of the point of intersection. Other embodiments are also described.

Abstract: A method, consisting of acquiring signals, indicative of temperatures at respective locations in a biological tissue, from a plurality of thermal sensors mounted on a probe in contact with the tissue, interpolating between the temperatures so as to produce a temperature distribution map, and displaying the temperature distribution map on a screen. The method also includes determining that at least one of the thermal sensors is a malfunctioning thermal sensor, and that remaining thermal sensors of the plurality are correctly operating. The at least one malfunctioning thermal sensor is assigned a first arbitrary temperature and the correctly operating thermal sensors are assigned second arbitrary temperatures.

Abstract: A system includes an electrical interface for communicating with a probe, and a processor. The electrical interface is configured to be inserted into a heart of a patient. The processor is configured to (A) receive from the probe, via the electrical interface, (i) position-signals indicative of a position of a distal tip of the probe in the heart, (ii) a contact-force indication indicative of a contact force exerted on the distal tip, and (iii) an electrophysiological (EP) measurement acquired by the distal tip at the position, (B) calculate a contact-force vector based on the contact-force indication received from the distal tip, and (C) based on the position-signals and on the contact-force vector, estimate a location, on an electro-anatomical map of the heart, at which the distal tip touches tissue, and to update the electro-anatomical map with the EP measurement, associated with the estimated location.

Abstract: A method, consisting of acquiring signals, indicative of temperatures at respective locations in a biological tissue, from a plurality of thermal sensors mounted on a probe in contact with the tissue, interpolating between the temperatures so as to produce a temperature distribution map, and displaying the temperature distribution map on a screen. The method also includes determining that at least one of the thermal sensors is a malfunctioning thermal sensor, and that remaining thermal sensors of the plurality are correctly operating. The at least one malfunctioning thermal sensor is assigned a first arbitrary temperature and the correctly operating thermal sensors are assigned second arbitrary temperatures.

Abstract: Cardiac catheterization is carried out by inserting a multi-electrode probe into a heart of a living subject, preparing a current position map of the electrodes to define respective locations of the electrodes, and recording electrograms from the electrodes. Activation times are annotated at the respective locations by analysis of the electrograms and generating an activation map. A region of the activation map is selected and earliest ones of the activation times in the selected region identified. The earliest activation times are graphically indicated.

Abstract: A method for data display includes acquiring a three-dimensional (3D) map of a lumen inside a body of a subject, transforming the 3D map of the lumen into a two-dimensional (2D) image by projecting the 3D map onto an annulus, and presenting the 2D image on a display screen.

Abstract: Values of a physiologic parameter at respective measured points in a heart are obtained. A 3-dimensional model of the heart is constructed, which includes first spatial elements that include the measured points and second spatial elements that do not include the measured points. The values of the parameter in the second spatial elements are interpolated and regional densities of the measured points in the model determined. The values of the parameter at the first spatial elements and the second spatial elements are displayed on a functional map of the heart, and a graphical characteristic of the map is modified responsively to the regional densities.

Abstract: A probe having a contact force sensor is inserted into a cardiac chamber and an image of the blood pool is generated. A portion of the blood pool is removed from the image to retain a remaining portion of the blood pool. A determination is made that the distal segment of the probe is within the remaining portion of the blood pool, and responsively to the determination the contact force sensor is manually zeroed.

Abstract: Described embodiments include a method that includes constructing a computerized electroanatomical model of a portion of a heart, the model including a mesh, which approximates the portion of the heart, and a plurality of points, at different respective locations on the mesh, having respective associated local activation times (LATs) that were ascertained from electrocardiographic signals acquired from the portion. The method further includes constructing a graph that interconnects the points and, based on the respective locations and LATs of the points, identifying, from a plurality of pathways, through the graph, from a first one of the points having a lowest one of the LATs to a second one of the points having a highest one of the LATs, both a shortest pathway and a longest pathway. The method further includes displaying the mesh, with the identified shortest pathway and longest pathway superimposed over the mesh. Other embodiments are also described.

Abstract: A 3-dimensional image is displayed in high resolution colors by generating a 3-dimensional model as a triangular mesh, converting the mesh into a grid of voxels, and assigning attribute values to a portion of the voxels. Laplacian interpolation based on the portion of the voxels is applied for iteratively calculating interpolated attribute values of other voxels. The voxels are rendered as a colored image according to the attribute values on a display.

Abstract: A probe having a contact force sensor is inserted into a cardiac chamber and an image of the blood pool is generated. A portion of the blood pool is removed from the image to retain a remaining portion of the blood pool. A determination is made that the distal segment of the probe is within the remaining portion of the blood pool, and responsively to the determination the contact force sensor is manually zeroed.

Abstract: A method for data display includes acquiring a three-dimensional (3D) map of a lumen inside a body of a subject, transforming the 3D map of the lumen into a two-dimensional (2D) image by projecting the 3D map onto an annulus, and presenting the 2D image on a display screen.