# US 9,872,638 B2 · Method and apparatus for determining information indicative of cardiac malfunctions > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,872,638 B2 - Document ID: US9872638B2 - Status: Granted - Kind: B2 - Application number: 14/899,782 - Filed: 2014-06-13 - Published: 2016-05-19 - Granted: 2018-01-23 - Earliest claimed: 2013-06-19 - Assignees: Precordior Oy - Applicants: Turun Yliopisto - Inventors: Tero Koivisto; Tuomas Valtonen; Mikko Pankaala; Kati Sairanen - Web page: https://patentgrep.com/patent/US9872638B2 ## CPC - A61B 5/1102: {Ballistocardiography} - A61B 5/35: by template matching - A61B 5/352: Detecting R peaks, e.g. for synchronising diagnostic apparatus; Estimating R-R interval - A61B 5/361: Detecting fibrillation - A61B 5/6804: {Garments; Clothes} - A61B 5/686: {Permanently implanted devices, e.g. pacemakers, other stimulators, biochips (A61B5/6861 takes precedence)} - A61B 5/6898: {Portable consumer electronic devices, e.g. music players, telephones, tablet computers} - A61B 5/1107: {Measuring contraction of parts of the body, e.g. organ or muscle} - A61B 5/7275: {Determining trends in physiological measurement data; Predicting development of a medical condition based on physiological measurements, e.g. determining a risk factor} - A61B 2562/0219: Inertial sensors, e.g. accelerometers, gyroscopes, tilt switches - A61B 2562/028: Microscale sensors, e.g. electromechanical sensors [MEMS] - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) ## Abstract An apparatus for determining information indicative of cardiac malfunctions includes a processing device (602) configured to detect whether the time-trend of a signal indicative of cardiovascular motion manifests an indicative phenomenon where the amplitude of a first heartbeat is greater than the amplitude of a second heartbeat and the temporary heartbeat rate is greater prior to the first heartbeat than prior to the second heartbeat. The processing device is further configured to produce an indicator of cardiac malfunction, e.g. an indicator of atrial fibrillation, in response to a situation in which the indicative phenomenon is detected to be present. ## Claims ### Claim 1 An apparatus comprising: a signal interface configured to receive a first signal indicative of cardiovascular motion; and a processing device coupled to the signal interface, the processing device being configured to: determine, based on the first signal, a correlation between amplitudes of heartbeats and quantities indicative of heartbeat rates prior to the heartbeats to detect whether a time-trend of the first signal manifests an indicative phenomenon where an amplitude of a first heartbeat is greater than an amplitude of a second heartbeat and a heartbeat rate is greater prior to the first heartbeat than prior to the second heartbeat, produce an indicator of cardiac malfunction in response to detection of the indicative phenomenon, and output the indicator to a user to treat or diagnose a patient. ### Claim 2 (depends on 1) The apparatus according to claim 1, wherein the processing device is configured to use a temporal length of a heartbeat period preceding the first heartbeat as a quantity indicative of the heartbeat rate prior to the first heartbeat, and a temporal length of a heartbeat period preceding the second heartbeat as a quantity indicative of the heartbeat rate prior to the second heartbeat. ### Claim 3 (depends on 1) The apparatus according to claim 1, wherein the processing device is configured to determine the correlation between the amplitudes of the heartbeats and temporal lengths of the heartbeat periods preceding the heartbeats, a negative correlation indicating presence of the indicative phenomenon. ### Claim 4 (depends on 1) The apparatus according to claim 1, wherein the processing device is configured to determine the correlation between the amplitudes of the heartbeats and heartbeat rates on heartbeat periods preceding the heartbeats, a positive correlation indicating presence of the indicative phenomenon. ### Claim 5 (depends on 1) The apparatus according to claim 1, wherein the processing device is configured to compute a correlation coefficient C indicative of the degree of the correlation between the amplitudes of the heartbeats and the quantities indicative of the heartbeat rates prior to the heartbeats: C=E{(A−μA)×(Q−μQ)}, where E is the expected value operator, A represents the amplitudes of the heartbeats, mA is the mean of the amplitudes, Q represents the quantities indicative of the heartbeat rates, and mQ is the mean of the quantities indicative of the heartbeat rates. ### Claim 6 (depends on 1) The apparatus according to claim 1, wherein the processing device is configured to extract or produce, from or on the basis of the first signal, one of the following which represent the amplitudes of the heartbeats: heights of AO-peaks caused by opening of the aortic valve, maximum peak-to-peak values within time windows each involving one of the AO-peaks, root-mean-square values computed over the time windows each involving one of the AO-peaks. ### Claim 7 (depends on 6) The apparatus according to claim 6, wherein the processing device is configured to extract, from the first signal, time periods between successive AO-peaks, temporal lengths of the time periods between successive AO-peaks being indicative of the heartbeat rates prior to the heartbeats. ### Claim 8 (depends on 6) The apparatus according to claim 6, wherein the signal interface is configured to receive a second signal indicative of electromagnetic phenomena related to cardiac activity, and the processing device is configured to extract, from the second signal, time periods between successive R-peaks, the R-peaks being caused by depolarization of the ventricular muscle tissue and temporal lengths of the time periods between the successive R-peaks being indicative of the heartbeat rates prior to the heartbeats. ### Claim 9 (depends on 1) The apparatus according to claim 1, wherein the processing device is configured to determine time variation indicative of variation of the temporal lengths of the heartbeat periods and to detect whether the time-trend of the first signal manifests the indicative phenomenon in response to a situation in which the detected time variation exceeds a threshold. ### Claim 10 (depends on 9) The apparatus according to claim 9, wherein the processing device is configured to determine a variation-quantity V indicative of the time variation: V = E ⁢ { ( TL - μ T ) 2 } μ T , where E is the expected value operator, TL represents the temporal lengths of the heartbeat periods, and mT is the mean of the temporal lengths of the heartbeat periods. ### Claim 11 (depends on 1) The apparatus according to claim 1, further comprising a sensor element configured to measure the first signal. ### Claim 12 (depends on 11) The apparatus according to claim 11, wherein the sensor element comprises one of the following: an accelerometer and a piezo-electronic sensor. ### Claim 13 (depends on 11) The apparatus according to claim 11, wherein the sensor element is a micro-electro-mechanical system. ### Claim 14 (depends on 11) The apparatus according to claim 11, wherein the apparatus is implantable under a skin of an individual under consideration. ### Claim 15 (depends on 11) The apparatus according to claim 11, wherein the apparatus is a mobile phone comprising the sensor element and the processing device. ### Claim 16 (depends on 11) The apparatus according to claim 11, wherein the apparatus is wearable and comprises a piece of clothing including the sensor element and the processing device connected to the sensor element. ### Claim 17 (depends on 1) The apparatus according to claim 1, wherein the processing device is configured to produce a signal expressing atrial fibrillation in response to a situation in which the indicative phenomenon is detected to be present. ### Claim 18 A method comprising: determining, based on a first signal indicative of cardiovascular motion, a correlation between amplitudes of heartbeats and quantities indicative of heartbeat rates prior to the heartbeats to detect whether a time-trend of the first signal manifests an indicative phenomenon where an amplitude of a first heartbeat is greater than an amplitude of a second heartbeat and a heartbeat rate is greater prior to the first heartbeat than prior to the second heartbeat; producing an indicator of cardiac malfunction in response to detection of the indicative phenomenon; and outputting the indicator to a user to treat or diagnose a patient. ### Claim 19 (depends on 18) The method according to claim 18, wherein a temporal length of a heartbeat period preceding the first heartbeat is used as a quantity indicative of the heartbeat rate prior to the first heartbeat, and a temporal length of a heartbeat period preceding the second heartbeat is used as a quantity indicative of the heartbeat rate prior to the second heartbeat. ### Claim 20 (depends on 18) The method according to claim 18, further comprising: determining the correlation between the amplitudes of the heartbeats and temporal lengths of the heartbeat periods preceding the heartbeats, a negative correlation indicating existence of the indicative phenomenon. ### Claim 21 (depends on 18) The method according to claim 18, further comprising: determining the correlation between the amplitudes of the heartbeats and heartbeat rates on heartbeat periods preceding the heartbeats, a positive correlation indicating existence of the indicative phenomenon. ### Claim 22 (depends on 18) The method according to claim 18, further comprising: computing a correlation coefficient C indicative of the degree of the correlation between the amplitudes of the heartbeats and the quantities indicative of the heartbeat rates prior to the heartbeats: C=E{(A−μA)×(Q−μQ)}, where E is the expected value operator, A represents the amplitudes of the heartbeats, mA is the mean of the amplitudes, Q represents the quantities indicative of the heartbeat rates, and mQ is the mean of the quantities indicative of the heartbeat rates. ### Claim 23 (depends on 18) The method according to claim 18, further comprising: extracting or producing, from or on the basis of the first signal, one of the following which represent the amplitudes of the heartbeats: heights of AO-peaks caused by opening of the aortic valve, maximum peak-to-peak values within time windows each involving one of the AO-peaks, root-mean-square values computed over the time windows each involving one of the AO-peaks. ### Claim 24 (depends on 23) The method according to claim 23, further comprising: extracting, from the first signal, time periods between successive AO-peaks, temporal lengths of the time periods between successive AO-peaks being indicative of the heartbeat rates prior to the heartbeats. ### Claim 25 (depends on 23) The method according to claim 23, further comprising: extracting, from a second signal indicative of electromagnetic phenomena related to cardiac activity, time periods between successive R-peaks, the R-peaks being caused by depolarization of the ventricular muscle tissue and temporal lengths of the time periods between the successive R-peaks being indicative of the heartbeat rates prior to the heartbeats. ### Claim 26 (depends on 18) The method according to claim 18, further comprising: determining time variation indicative of variation of the temporal lengths of the heartbeat periods and to detect whether the time-trend of the first signal manifests the indicative phenomenon in response to a situation in which the detected time variation exceeds a threshold. ### Claim 27 (depends on 26) The method according to claim 26, further comprising: determining a variation-quantity V indicative of the time variation: V = E ⁢ { ( TL - μ T ) 2 } μ T , where E is the expected value operator, TL represents the temporal lengths of the heartbeat periods, and mT is the mean of the temporal lengths of the heartbeat periods. ### Claim 28 (depends on 18) The method according to claim 18, further comprising: producing a signal expressing atrial fibrillation in response to a situation in which the indicative phenomenon is detected to be present. ### Claim 29 A non-transitory computer-readable medium on which is stored a computer program which comprises computer executable instructions for controlling a programmable processor to: determine, based on a first signal indicative of cardiovascular motion, a correlation between amplitudes of heartbeats and quantities indicative of heartbeat rates prior to the heartbeats to detect whether a time-trend of the first signal manifests an indicative phenomenon where an amplitude of a first heartbeat is greater than an amplitude of a second heartbeat and a heartbeat rate is greater prior to the first heartbeat than prior to the second heartbeat; produce an indicator of cardiac malfunction in response to detection of the indicative phenomenon; and output the indicator to a user to treat or diagnose a patient.