# US 2014/0155772 A1 · Validity test adaptive constraint modification for cardiac data used for detection of state changes > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0155772 A1 - Document ID: US20140155772A1 - Status: Published application - Kind: A1 - Application number: 14/177,066 - Filed: 2014-02-10 - Published: 2014-06-05 - Earliest claimed: 2010-04-29 - Assignees: Flint Hills Scientific, L.L.C. - Applicants: Flint Hills Scientific, L.L.C. - Inventors: Mark G. Frei; Ivan Osorio - Web page: https://patentgrep.com/patent/US20140155772A1 ## CPC - A61N 1/36064: {Epilepsy} - A61B 5/02405: {Determining heart rate variability} - A61B 5/0245: by using sensing means generating electric signals, {i.e. ECG signals} - A61B 5/352: Detecting R peaks, e.g. for synchronising diagnostic apparatus; Estimating R-R interval - A61B 5/4094: {Diagnosing or monitoring seizure diseases, e.g. epilepsy} - A61N 1/36053: {adapted for vagal stimulation (A61N1/36114 takes precedence)} - A61N 1/36139: {with automatic adjustment} - 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) - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) ## Abstract Methods, systems, and apparatus for quantifying the quality of a fiducial time marker for a candidate heart beat, quantifying the quality of a candidate heart beat, or determining a time of beat sequence of the patient's heart. A fiducial time marker is obtained for a candidate heart beat. A quality index of said candidate heart beat is set to a first value. The candidate heart beat is tested with at least one beat validity test. At least a second value is added to said quality index of said candidate heart beat if said candidate heart beat passes said at least one beat validity test. The candidate heart beat is tested with at least a second heart beat validity test. At least a third value is added to said quality index of said candidate heart beat if said candidate heart beat passes said at least second heart beat validity test. In one class of beat validity test, a constraint defining a pass is modified at one or more times after the most recent prior valid heart beat that is greater than a constraint modification time threshold ## Claims ### Claim 1 A non-transitory computer readable program storage unit encoded with instructions that, when executed by a computer, perform a method for determining a time of beat sequence of the patient's heart, comprising: obtaining a time series of fiducial time markers for candidate heart beats; identifying valid heart beats from said candidate heart beats by subjecting a plurality of said candidate heart beats to at least one beat validity test, said at least one beat validity test comprising at least one interbeat interval test applied to a candidate heart beat interval derived from a candidate heart beat and at least one prior heart beat; accepting as valid heart beats the candidate heart beats that pass said at least one beat validity test, wherein a constraint used in defining said pass is modified after a time period since the most recent prior valid heart beat reaches or exceeds a constraint modification time threshold, wherein said accepting comprises accepting as a valid heart beat at least one candidate heart beat that failed said at least one beat validity test prior to said constraint being modified; detecting an epileptic seizure using a seizure detection algorithm based on said accepted valid heart beats; and performing at least one responsive action selected from the group consisting of issuing a detection for an epileptic seizure event; delivering a neurostimulation therapy to the patient to treat an epileptic seizure event; warning at least one of a caregiver, the patient, or a physician; and logging said modified constraint to a memory. ### Claim 2 (depends on 1) The non-transitory computer readable program storage unit of claim 1, wherein the constraint is modified by relaxing said constraint by from about 1% to about 50%. ### Claim 3 (depends on 1) The non-transitory computer readable program storage unit of claim 1, wherein the constraint is modified by relaxing said constraint by greater than about 50%. ### Claim 4 (depends on 1) The non-transitory computer readable program storage unit of claim 1, wherein the constraint is modified by tightening said constraint by greater than about 1%. ### Claim 5 (depends on 1) The non-transitory computer readable program storage unit of claim 1, wherein the constraint is modified once after the constraint modification time threshold is passed. ### Claim 6 (depends on 1) The non-transitory computer readable program storage unit of claim 1, wherein the constraint is modified a plurality of times after the constraint modification time threshold is passed. ### Claim 7 (depends on 1) The non-transitory computer readable program storage unit of claim 1, wherein the constraint is modified according to a step function at one or more times after the constraint modification time threshold is passed. ### Claim 8 (depends on 1) The non-transitory computer readable program storage unit of claim 1, wherein the constraint is modified according to a linear function over a range of times after the constraint modification time threshold is passed. ### Claim 9 (depends on 1) The non-transitory computer readable program storage unit of claim 1, wherein the constraint is modified according to a non-linear function over a range of times after the constraint modification time threshold is passed. ### Claim 10 (depends on 1) The non-transitory computer readable program storage unit of claim 1, wherein the constraint is modified to no more than a finite maximum value or no less than a finite minimum value. ### Claim 11 (depends on 1) The non-transitory computer readable program storage unit of claim 1, wherein said fiducial time markers are selected from one or more of: a time-stamped R-wave peak; a time-stamped R-wave threshold crossing; a time-stamped P-wave peak; a time-stamped P-wave threshold crossing; a time-stamped T-wave peak; or a time-stamped T-wave threshold crossing. ### Claim 12 A method, comprising: identifying a plurality of candidate heart beats in a first time window, wherein said plurality of candidate heart beats comprises a first fiducial marker for a most recent candidate heart beat and at least a second fiducial marker for a prior candidate heart beat, wherein said prior candidate heart beat did not pass a beat validity test; applying a first beat validity test to each said candidate heart beat, said a least one beat validity test comprising at least one interbeat interval test applied to a candidate heart beat interval derived from a fiducial marker for the candidate heart beat and a fiducial marker for an immediately preceding candidate heart beat; accepting said most recent candidate heart beat as a valid heart beat if said most recent candidate heart beat passes said at least one beat validity test; accepting said prior candidate heart beat as a valid heart beat within said first time window if the time period from said second fiducial marker to said first fiducial marker reaches or exceeds a constraint modification time threshold; detecting an epileptic seizure using a seizure detection algorithm based on said accepted valid heart beats; and performing at least one responsive action selected from the group consisting of issuing a detection for an epileptic seizure event; delivering a neurostimulation therapy to the patient to treat an epileptic seizure event; warning at least one of a caregiver, the patient, or a physician; and logging said modified constraint to a memory. ### Claim 13 (depends on 12) The method of claim 12, wherein said fiducial marker is a fiducial time marker. ### Claim 14 (depends on 13) The method claim 13, wherein said fiducial marker is at least one of: a time stamped R-wave peak; a time stamped R-wave threshold crossing; a time stamped P-wave peak; a time stamped P-wave threshold crossing; a time stamped T-wave peak; or a time stamped T-wave threshold crossing. ### Claim 15 (depends on 13) The method of claim 13, wherein the method further comprises modifying a constraint used in defining said pass after a time period since a most recent prior valid heart beat reaches or exceeds said constraint modification time threshold. ### Claim 16 (depends on 15) The method of claim 15, wherein the constraint is modified a plurality of times after the constraint modification time threshold is reached or exceeded. ### Claim 17 A non-transitory computer readable program storage unit encoded with instructions that, when executed by a computer, perform a method for determining a time of beat sequence of the patient's heart, comprising: obtaining a time series of fiducial markers for candidate heart beats, wherein said time series comprises a first fiducial marker for a most recent candidate heart beat and at least a second fiducial marker for a prior candidate heart beat; subjecting at least said most recent candidate heart beat to at least one beat validity test, said at least one beat validity test comprising at least one interbeat interval test applied to a most recent candidate heart beat interval derived from the most recent candidate heart beat and at least one prior candidate heart beat; performing at least one of accepting said most recent candidate heart beat as a valid heart beat if said most recent candidate heart beat passes said at least one beat validity test, and rejecting said most recent candidate heart beat to provide a rejected most recent candidate heart beat if said most recent candidate heart beat does not pass said at least one beat validity test; accepting said rejected most recent candidate heart beat as a valid heart beat after the lapse of a constraint threshold time following said first time marker; using said valid heart beat in a seizure detection algorithm; and in response to a seizure detection by said seizure detection algorithm, performing at least one responsive action selected from the group consisting of issuing a detection for an epileptic seizure event; delivering a neurostimulation therapy to the patient to treat an epileptic seizure event; warning at least one of a caregiver, the patient, or a physician; and logging said modified constraint to a memory. ### Claim 18 (depends on 17) The non-transitory computer readable program storage unit of claim 17, wherein the fiducial marker is at least one of a time marker, an R-wave threshold crossing, an R-wave peak, a T-wave threshold crossing, a T-wave peak, a P-wave threshold crossing, or a P-wave peak. ### Claim 19 (depends on 17) The non-transitory computer readable program storage unit of claim 17, wherein the method further comprises modifying said constraint threshold time after a time period since a most recent prior valid heart beat reaches or exceeds said constraint threshold time. ### Claim 20 (depends on 19) The non-transitory computer readable program storage unit of claim 19, wherein the constraint is modified a plurality of times after the constraint modification time threshold is reached or exceeded.