# US 9,433,364 B2 · Focal point identification and mapping > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,433,364 B2 - Document ID: US9433364B2 - Status: Granted - Kind: B2 - Application number: 14/156,903 - Filed: 2014-01-16 - Published: 2014-07-17 - Granted: 2016-09-06 - Earliest claimed: 2013-01-17 - Assignees: Cardioinsight Technologies, Inc. - Applicants: Cardioinsight Technologies, Inc. - Inventors: Qingguo Zeng; Remi Dubois; Ping Jia; Ryan Bokan; Venkatesh Vasudevan; Charulatha Ramanathan; Maria Strom; Brian P. George - Web page: https://patentgrep.com/patent/US9433364B2 ## CPC - A61B 5/04012 - A61B 5/0044: {for the heart} - A61B 5/044 - A61B 5/486: {Biofeedback (using electroencephalography [EEG] A61B5/375)} - A61N 1/36: for stimulation - A61B 5/0452 - A61B 18/1492: {having a flexible, catheter-like structure, e.g. for heart ablation (A61B18/1477 takes precedence)} - A61B 2576/023: for the heart - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) - A61N: ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY (measurement of bioelectric currents A61B; surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body A61B18/00; anaesthetic apparatus in general A61M; incandescent lamps H01K; infrared radiators for heating H05B) ## Abstract A method can determine one or more origins of focal activation. The method can include computing phase for the electrical signals at a plurality of nodes distributed across a geometric surface based on the electrical data across time. The method can determine whether or not a given candidate node of the plurality of nodes is a focal point based on the analyzing the computed phase and magnitude of the given candidate node. A graphical map can be generated to visualize focal points detected on the geometric surface. ## Claims ### Claim 1 A non-transitory computer-readable medium having instructions executable by a processor for performing a method comprising: computing phase values for signals of each of a plurality of nodes on a geometric surface region associated with tissue of a patient, a subset of the nodes surrounding a given node of the plurality of nodes defining neighboring nodes of the given node; analyzing the computed phase value of the given node relative to the computed phase values of each of a set of neighboring nodes of the given node over an activation time period associated with the given node; determining if the given node is a focal point based on the analyzing; repeating the computing, analyzing and determining for each node of at least a substantial portion of the plurality of nodes to provide focal point data specifying a spatial location corresponding to each detected focal point for the geometric surface region; and generating and displaying a graphical map based on the focal point data. ### Claim 2 (depends on 1) The medium of claim 1, wherein the neighboring nodes comprise an arrangement of nodes having a plurality of layers that provide a neighborhood of the nodes relative to the given node. ### Claim 3 (depends on 2) The medium of claim 2, wherein the number of layers for each neighborhood is a programmable parameter. ### Claim 4 (depends on 2) The medium of claim 2, wherein analyzing the computed phase values further comprises: comparing the computed phase value of each given node relative to the computed phase value of each node in its set of neighboring nodes over the activation time period; assigning a score to one of the given node and its neighboring node based on each comparison, wherein each detected focal point for the geometric surface region is detected based on the scores assigned to each of the nodes. ### Claim 5 (depends on 4) The medium of claim 4, further comprising: aggregating the scores assigned to each of the nodes over a plurality of activation time periods; and generating the graphical map of the geometric surface region based on the focal point data including the aggregated scores assigned to each of the nodes. ### Claim 6 (depends on 4) The medium of claim 4, wherein the score assigned to each of the nodes comprises a value that varies as a function of a distance between each given node and the node to which the comparison is made. ### Claim 7 (depends on 1) The medium of claim 1, wherein the method further comprises: detecting the activation for at least a substantial portion of the plurality of nodes; generating an activation mask for the given node based on the activation detected for at least one of the plurality of nodes, the activation mask specifying a set of at least one activation time period having a beginning and ending time, the beginning time corresponding to when phase value of a signal at the least one of the plurality of nodes has a given value and the ending time corresponding to when the phase value of the signal at the least one of the plurality of nodes has another value; and identifying a set of focal candidate nodes in response to applying the activation mask to the computed phase values computed for each of the plurality nodes on the geometric surface region, wherein determining whether the given node is a focal point is performed only with respect to each given candidate node in the identified set of focal candidate nodes. ### Claim 8 (depends on 7) The medium of claim 7, wherein activation mask is a temporal activation mask, wherein generating the activation mask further comprises generating a magnitude activation mask that specifies a minimum magnitude for the signals at each of the plurality of nodes on the geometric surface region, wherein the set of focal candidate nodes is identified in response to applying both the temporal activation mask and the magnitude activation mask. ### Claim 9 (depends on 7) The medium of claim 7, further comprising: computing a size of an activation region across the geometric surface region according to which of the plurality of nodes are activated for a respective activation time in a corresponding time interval, and determining whether or not each given candidate node is a focal point based on the computed size of the activation region for at least one time interval. ### Claim 10 (depends on 9) The medium of claim 9, the determining further comprising: detecting that a respective one of the given candidate nodes is a focal point if newly activated nodes for at least one other activation period following the respective activation time period are connected with the activation region that is activated for the respective activation time period and if the computed size of the activation region for the other activation time exceeds a minimum size parameter. ### Claim 11 (depends on 10) The medium of claim 10, further comprising generating the graphical map to represent each focal points that is detected for the geometric surface region. ### Claim 12 (depends on 9) The medium of claim 9, determining that one of the given candidate nodes is not a focal point if nodes activated for a subsequent activation time are unconnected with the activation region that is activated for the respective activation time and the computed size has not changed over a predetermined time period. ### Claim 13 (depends on 1) The medium of claim 1, wherein the geometric surface region comprises one of an epicardial surface, an endocardial surface or another cardiac envelope. ### Claim 14 (depends on 1) The medium of claim 1, wherein the method further comprises solving an inverse problem to compute reconstructed electrical signals as the signals for each of the nodes on the geometric surface region based on electrical data acquired from the patient, the computed phase value for each of the nodes being computed based on the reconstructed electrical signals for the respective nodes. ### Claim 15 (depends on 1) The medium of claim 1, wherein the signals for each of the plurality of nodes are derived based on at least one of invasively acquired electrical data for the patient or non-invasively acquired electrical data for the patient. ### Claim 16 A system comprising: memory to store data and machine readable instructions; and a processor to access the memory and execute the machine readable instructions, the machine readable instructions comprising: a phase calculator programmed to compute phase values for electrical signals at a plurality of nodes distributed across a geometric surface corresponding to patient tissue; a focal detector programmed to determine whether or not a given candidate node of the plurality of nodes is a focal point based on analyzing the computed phase value of the given candidate node relative to the phase value of each node in a set of nodes neighboring and surrounding the given node for an activation time interval associated with the given candidate node, wherein the focal detector is programmed to repeat the analyzing and determining for each candidate node of at least a substantial portion of the plurality of nodes to store focal point data in the memory; and a map generator programmed to generate a display of a graphical map representing at least one of the focal points detected on the geometric surface based on the focal point data. ### Claim 17 (depends on 16) The system of claim 16, wherein focal detector further comprises a phase comparator programmed to compare the computed phase value of each given candidate node relative to the phase value of each node in its respective set of neighboring nodes over the activation time period, the phase comparator to assign a score to one of the given candidate node and its neighboring node based on each comparison such that the focal detector determines which of the plurality of nodes are focal points for the geometric surface based on an aggregate score that is assigned to of each of the plurality of nodes and stored in the focal point data, wherein the map generator is to generate the graphical map of the geometric surface based on the focal point data including the aggregated scores assigned to each of the nodes. ### Claim 18 (depends on 17) The system of claim 17, wherein the score assigned to each of the nodes comprises a value that varies as a function of a distance between each given candidate node and the node to which the comparison is made. ### Claim 19 (depends on 16) The system of claim 16, wherein the focal detector further comprises: an activation detector programmed to determine the activation time interval for at least a substantial portion of the plurality of nodes; a mask generator programmed to generate an activation mask for the given candidate node based on the activation time interval detected for at least one of the plurality of nodes, the activation mask specifying a set of at least one activation time intervals having a beginning and ending time; and a candidate selector programmed to identify a set of focal candidate nodes in response to applying the activation mask to the phase value computed for each of the plurality nodes on the geometric surface. ### Claim 20 (depends on 19) The system of claim 19, wherein activation mask is a temporal activation mask, the mask generator further to provide a magnitude activation mask that specifies a minimum magnitude for the electrical signals at each of the plurality of nodes on the geometric surface, and wherein the candidate selector is programmed to identify the set of focal candidate nodes in response to applying both the temporal activation mask to the computed activation time intervals for each of the plurality of nodes and the magnitude activation mask to the electrical signals at each of the plurality of nodes. ### Claim 21 (depends on 19) The system of claim 19, wherein the focal detector further comprises: a size calculator programmed to compute a size of an activation region across the geometric surface according to which of the plurality of nodes are activated for a respective activation time in a corresponding time interval, and wherein the focal detector is further programmed to determine whether or not each given focal candidate node is a focal point based on the computed size of the activation region for at least one time interval. ### Claim 22 (depends on 21) The system of claim 21, wherein the focal detector further comprises: a continuity detector programmed to provide continuity data to indicate if newly activated nodes for at least one other activation interval following the respective activation time interval are connected with the activation region that was activated for the respective activation time period, wherein the focal detector is to determine that each given focal candidate node is a focal point based on the continuity data and based on the computed size of the activation region for the other activation time exceeding a minimum size parameter. ### Claim 23 (depends on 22) The system of claim 22, wherein the focal detector is further programmed to determine that one of the given candidate nodes is not a focal point based on the continuity data indicating that newly activated nodes for at least one other activation interval following the respective activation time interval are unconnected with the activation region that was activated for the respective activation time period and the computed size has not changed over a predetermined time period. ### Claim 24 (depends on 16) The system of claim 16, wherein the geometric surface comprises one of an epicardial surface, an endocardial surface or another cardiac envelope. ### Claim 25 (depends on 24) The system of claim 24, further comprising: a measurement system configured to measure non-invasively electrical activity for the geometric surface of the patient and provide corresponding electrical measurement data; wherein the machine instructions further comprise a reconstruction function programmed to solving an inverse problem to compute reconstructed electrical signals, which correspond to the electrical signals, for each of the nodes on the geometric surface based on electrical measurement data and geometry data, the phase value for each of the plurality of nodes being computed based on the reconstructed electrical signals for the respective nodes. ### Claim 26 (depends on 16) The system of claim 16, further comprising a measurement system configured to measure invasively electrical activity for the geometric surface, wherein the electrical signals for each of the plurality of nodes are derived based on the invasively measured electrical activity. ### Claim 27 (depends on 16) The system of claim 16, further comprising a therapy system to control delivery of a therapy to a selected location on the geometric surface based on the focal point data. ### Claim 28 A method comprising: storing, in memory, electrical data representing electrical signals for a geometric surface corresponding to patient tissue; computing, by a processor, phase values for the electrical signals at a plurality of nodes distributed across the geometric surface based on the electrical data; determining, by a processor, whether or not a given candidate node of the plurality of nodes is a focal point based on analyzing the computed phase value of the given candidate node relative to the phase value of each node in a set of nodes neighboring and surrounding the given node for an activation time interval associated with the given candidate node, focal point data being stored in the memory based on the determination; and repeating the computing and the determining for each candidate node of at least a substantial portion of the plurality of nodes to provide the focal point data specifying a spatial location corresponding to each detected focal point on the geometric surface; providing a graphical map to a display to visualize at least one of the focal points detected on the geometric surface based on the focal point data.