A method includes obtaining multiple local activation times (LATs) at different respective measurement locations on an anatomical surface of a heart. The method further includes computing respective directions of electrical propagation at one or more sampling locations on the anatomical surface, by, for each sampling location, selecting a respective subset of the measurement locations for the sampling location, constructing a set of vectors, each of at least some of the vectors including, for a different respective measurement location in the subset, three position values derived from respective position coordinates of the measurement location and an LAT value derived from the LAT at the measurement location, and computing the direction of electrical propagation at the sampling location based on a Principal Component Analysis (PCA) of a 4×4 covariance matrix for the set of vectors. The method further includes indicating the directions of electrical propagation on a display.

A method includes calculating a first medial-axis tree graph of a volume of an organ of a patient in a first computerized anatomical map of the volume, acquired at a first time. A second medial-axis tree graph is calculated, of a volume of the organ of the patient in a second computerized anatomical map of the volume, acquired at a second time that is different from the first time. A deviation is detected and estimated, between the first and second tree-graphs. Using the estimated deviation, the first and second medial-axis tree graphs are registered with one another. Using the registered first and second tree graphs, the first and second computerized anatomical maps are combined.

A method includes receiving a bipolar signal sensed by a pair of electrodes at a location in a heart of a patient. One or more electrocardiogram (ECG) signals are received, sensed by body-surface electrodes attached to the patient. Two or more successive QRS complexes are identified in the bipolar signal. One or more activations are detected in the bipolar signal, which occur within a window-of-interest that begins at least a given time with respect to the identified QRS complexes. The detected activations are checked whether they are late potentials, by verifying whether (i) the activations do not coincide with a predefined event observed in the ECG signals, and (ii) the activations are repeatable in the successive QRS complexes. In response to deciding that at least one of the detected activations is a late potential, the latest of the at least one of the late potentials is visualized to a user.

A method includes receiving a bipolar signal sensed by a pair of electrodes at a location in a heart of a patient. One or more electrocardiogram (ECG) signals are received, sensed by body-surface electrodes attached to the patient. Two or more successive QRS complexes are identified in the bipolar signal. One or more activations are detected in the bipolar signal, which occur within a window-of-interest that begins at least a given time with respect to the identified QRS complexes. The detected activations are checked whether they are late potentials, by verifying whether (i) the activations do not coincide with a predefined event observed in the ECG signals, and (ii) the activations are repeatable in the successive QRS complexes. In response to deciding that at least one of the detected activations is a late potential, the latest of the at least one of the late potentials is visualized to a user.

A system for differentiating between magnetic field distortion and physical movement in a hybrid magnetic and impedance tracking system can comprise a first drive patch and a second drive patch configured to generate an electrical field within the body for locating an electrode on the medical device, a magnetic localization system configured to generate a magnetic field, a magnetic sensor configured to receive signals from the magnetic localization system, and an electronic control unit configured to receive location data from the impedance localization system and magnetic sensor location data from the magnetic localization system. The electronic control circuit can be configured to detect a location change of the magnetic sensor and use the drive patch location data and magnetic sensor location data to determine whether the detected location change of the magnetic sensor is caused by a magnetic field distortion or a physical movement of the magnetic sensor.

A method, including receiving, from electrodes positioned within a heart, first signals from at least three of the electrodes indicating electrical activity in tissue with which the at least three of the electrodes engage, and second signals indicating locations of the at least three electrodes. The second signals are processed to compute the locations of the at least three electrodes and to determine a geometric center of the locations. Based on the signals, an electroanatomical map is generated for an area of the tissue including the geometric center, and an arrhythmia focus is determined in the map. A circle is presented, and within the circle, a region of the map is presented including the geometric center and the focus so that the geometric center on the map aligns with a center of the circle, the region within the circle indicating a spatial relationship between the geometric center and the focus.

A method, including receiving, from electrodes positioned within a heart, first signals from at least three of the electrodes indicating electrical activity in tissue with which the at least three of the electrodes engage, and second signals indicating locations of the at least three electrodes. The second signals are processed to compute the locations of the at least three electrodes and to determine a geometric center of the locations. Based on the signals, an electroanatomical map is generated for an area of the tissue including the geometric center, and an arrhythmia focus is determined in the map. A circle is presented, and within the circle, a region of the map is presented including the geometric center and the focus so that the geometric center on the map aligns with a center of the circle, the region within the circle indicating a spatial relationship between the geometric center and the focus.

A system for identifying vortices in a vector map including multiple vectors, the system includes a processor and an output device. The processor is configured to: (i) define one or more closed loops on the vector map, and (ii) for each closed loop, identify a plurality of the vectors that cross the closed loop, calculate a vector sum of the identified vectors, and decide based on the vector sum whether a vortex is located inside the closed loop. The output device is configured to indicate one or more identified vortices to a user.

A system for identifying vortices in a vector map including multiple vectors, the system includes a processor and an output device. The processor is configured to: (i) define one or more closed loops on the vector map, and (ii) for each closed loop, identify a plurality of the vectors that cross the closed loop, calculate a vector sum of the identified vectors, and decide based on the vector sum whether a vortex is located inside the closed loop. The output device is configured to indicate one or more identified vortices to a user.

Poroelastic materials, methods of making such materials, biosensors comprising such materials, and methods of making and using such biosensors. According to one aspect, a poroelastic material is formed by a process that includes depositing a prepolymer composition on a substrate, annealing the prepolymer composition in a pressurized steam environment at a temperature and for a duration sufficient to form a porous medium having a solid matrix formed of a polymer derived from the prepolymer composition, infiltrating the porous medium with a liquid that includes electrically conductive nanomaterials such that the electrically conductive nanomaterials are located within pores of the porous medium, and evaporating the liquid such that the electrically conductive nanomaterials remain in and/or connected through the pores of the porous medium.