ELECTRONIC Sphygmomanometer AND METHOD FOR DETECTING ATRIAL FIBRILLATION USING ELECTRONIC Sphygmomanometer

Abstract

To accurate determine whether or not there is a possibility of an occurrence of atrial fibrillation in a relatively short time per measurement occasion in an electronic sphygmomanometer.SOLUTION: An electronic sphygmomanometer includes a cuff pressure control part for executing control to increase or reduce the pressure of a cuff, a pressure detection unit for detecting a cuff pressure signal, and a blood pressure measuring unit for taking out a pulse wave signal indicating a pulse wave superposed on the cuff pressure signal, and measuring the blood pressure on the basis of the pulse wave signal. A pulse wave interval calculation unit obtains a data group indicating a pulse wave interval on the basis of a pulse wave signal obtained only in one pressurizing process or one depressurizing process for each measurement occasion for a certain subject (S102). A determination unit tallies data groups on three or more measurement occasions of the subject to obtain an average value of the pulse wave intervals, and determines whether or not there is a possibility of an occurrence of atrial fibrillation on the basis of whether or not data on an irregular pulse wave exceeding an acceptable range determined beforehand for the average value exists in the tallied data groups (S104).SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an electronic blood pressure monitor, and more particularly to an electronic blood pressure monitor capable of determining whether or not atrial fibrillation may have occurred. The present invention also relates to an atrial fibrillation determination method for determining whether or not atrial fibrillation may have occurred in an electronic blood pressure monitor. [Background technology]

[0002] Conventionally, some home electronic blood pressure monitors are equipped with a function for determining whether or not atrial fibrillation may have occurred based on acquired pulse wave information (for example, an automatic electronic blood pressure monitor M7 Intelli IT manufactured by Omron Healthcare Co., Ltd.). For example, a subject uses such a blood pressure monitor to perform blood pressure measurements multiple times (for example, three times) in one measurement opportunity. Then, a pulse wave interval, which is the interval between pulse wave signals acquired in each blood pressure measurement, is calculated, and the pulse wave interval is compared with an average pulse wave interval in that blood pressure measurement. Then, a pulse wave interval that exceeds a preset allowable value, for example, ±25%, is determined to be an irregular pulse wave, and the number of occurrences of the irregular pulse wave is counted. Depending on how many measurements in which an irregular pulse wave has occurred a predetermined number of times or more in multiple consecutive blood pressure measurements, it is determined whether or not atrial fibrillation may have occurred.

[0003] For example, Non-Patent Document 1 (M. Ishizawa et al. "Development of a Novel Algorithm to Detect Atrial Fibrillation Using an Automated Blood Pressure Monitor With an Irregular Heartbeat Detector", Circulation Journal, Japan Circulation Society, September 2019, Vol. 83, No. 12, pp. 2416-2417) reports that atrial fibrillation may have occurred if, among three consecutive blood pressure measurements, at least one irregular pulse wave occurred in two or more measurements. As a result, the sensitivity (the proportion of patients with atrial fibrillation correctly detected as having atrial fibrillation) was 95.5%, and the specificity (the proportion of patients without atrial fibrillation correctly detected as not having atrial fibrillation) was 96.5%, showing a very accurate determination. [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] M. Ishizawa et al., “Development of a Novel Algorithm to Detect Atrial Fibrillation Using an Automated Blood Pressure Monitor With an Irregular Heartbeat Detector,” Circulation Journal, Japan Circulation Society, September 2019, Vol. 83, No. 12, p. 2416-2417 Summary of the Invention [Problem to be solved by the invention]

[0005] Generally, the pulse wave number obtained during one blood pressure measurement is about 10 beats per minute. Therefore, if screening for atrial fibrillation is performed using the pulse wave number obtained during one blood pressure measurement, it is thought that a stable diagnosis cannot be made.

[0006] However, it can be said that always measuring blood pressure three times at each measurement opportunity is very bothersome for the subject because the total time required for one measurement is long and the subject feels a sense of restraint caused by repeated pressure from the cuff more than the systolic blood pressure. For example, one blood pressure measurement generally takes about 40 to 60 seconds. It is also recommended to leave a time interval of 30 seconds to 1 minute between measurements. Therefore, to measure blood pressure three times in a row, a total time of at least 180 seconds or more (40 seconds for the first measurement + 30 seconds for the interval + 40 seconds for the second measurement + 30 seconds for the interval + 40 seconds for the third measurement) is required, as shown in Figure 14.

[0007] Therefore, an object of the present invention is to provide an electronic blood pressure monitor that can accurately determine whether or not atrial fibrillation may have occurred within a relatively short period of time per measurement opportunity, and a method for determining atrial fibrillation in an electronic blood pressure monitor. [Means for solving the problem]

[0008] In order to solve the above problems, the electronic blood pressure monitor disclosed herein comprises: An electronic blood pressure monitor that measures blood pressure by an oscillometric method based on an arterial pulse wave passing through a measurement site, a cuff pressure control unit that controls the pressure of a cuff attached to a measurement site to be increased or decreased; a pressure detection unit that detects a cuff pressure signal representing the pressure of the cuff during a pressurization process or a depressurization process by the cuff pressure control unit; a blood pressure measuring unit that extracts a pulse wave signal representing the pulse wave superimposed on the cuff pressure signal and measures blood pressure based on the pulse wave signal; a pulse wave interval calculation unit for calculating a data set representing a pulse wave interval based on the pulse wave signal obtained during only one pressurization process or one depressurization process for each measurement occasion for a certain subject; a determination unit that calculates an average value of the pulse wave intervals by aggregating the data group for three or more measurement occasions of the subject, and determines whether or not atrial fibrillation may have occurred based on whether or not data of an irregular pulse wave that exceeds a predetermined allowable range with respect to the average value is present in the aggregated data group; Equipped with 、 The time intervals between the three measurement occasions are within a predefined tolerance period. It is characterized by:

[0009] "One measurement opportunity" means an opportunity for measuring blood pressure once the subject wears the cuff. In the present invention, it is intended that one blood pressure measurement is performed per measurement opportunity.

[0010] "Only one pressurization process or one depressurization process" means only one blood pressure measurement in one measurement opportunity. The number of data included in one data group is typically expected to be about 10.

[0011] "Three measurement opportunities" may, for example, be three measurement opportunities, such as one in the morning, one in the afternoon, and one in the evening of a certain day, or one in the morning of a certain day, one in the morning of the following day, and one in the morning of the following day.

[0012] "Pulse wave interval" means the peak-to-peak interval of a pulse wave (or the equivalent bottom-to-bottom interval).

[0013] An "irregular pulse wave" refers to a pulse wave whose pulse wave interval exceeds a predetermined allowable range from the average value. The "predetermined allowable range" refers to a range of ±25% from the average value, for example. Moreover, the "predetermined permissible period" means, for example, one day.

[0014] In the electronic blood pressure monitor disclosed herein, blood pressure is measured based on the pulse wave of an artery passing through a portion to be measured as follows. First, the subject attaches a cuff to the portion to be measured and the measurement opportunity arrives. The cuff pressure control unit places the pressure of the cuff attached to the portion to be measured in an inflating process or a deflating process. During the inflating process or the deflating process by the cuff pressure control unit, the pressure detection unit detects a cuff pressure signal representing the pressure of the cuff. The blood pressure measurement unit extracts a pulse wave signal representing the pulse wave superimposed on the cuff pressure signal, and measures blood pressure based on this pulse wave signal. In this manner, one blood pressure measurement is performed per measurement opportunity.

[0015] Here, the pulse wave interval calculation unit obtains a data group representing the pulse wave interval based on the pulse wave signal obtained only in one pressurization process or one depressurization process for each measurement occasion for a certain subject. The number of data included in one data group is typically assumed to be about 10. As described above, it is considered that with about 10 pieces of data, it is not possible to accurately determine whether or not atrial fibrillation has occurred. Therefore, in this electronic blood pressure monitor, the determination unit counts the data group for three or more measurement occasions for the subject, calculates the average value of the pulse wave interval, and determines whether or not atrial fibrillation has occurred based on whether or not there is data of an irregular pulse wave that exceeds a predetermined allowable range for the average value in the counted data group. In this case, the number of data on which the determination is based is approximately the same as or greater than the number of data of three consecutive blood pressure measurements in a conventional method (referring to a method of measuring blood pressure three times consecutively per measurement occasion as described in Non-Patent Document 1; the same applies below). Therefore, this electronic blood pressure monitor can accurately determine whether or not atrial fibrillation has occurred. In particular, with this electronic blood pressure monitor, the time intervals between the three measurement opportunities are within a predetermined allowable period, so that the reliability of the determination can be improved.

[0016] In addition, in this electronic blood pressure monitor, since it is sufficient to perform one blood pressure measurement per measurement opportunity to determine whether or not there is a possibility of atrial fibrillation occurring, the time required per measurement opportunity is relatively short. Note that multiple blood pressure measurements may be performed per measurement opportunity.

[0017] In one embodiment, the electronic blood pressure monitor comprises: The determination unit is calculating an average value of the pulse wave interval for each of the data groups for each of the measurement occasions, and determining whether or not data of the irregular pulse wave is present in the data group, thereby obtaining an individual determination result indicating whether or not an irregular pulse wave has occurred for each of the measurement occasions; Only when the individual judgment result that the irregular pulse wave occurred is obtained for two or more of the three measurement occasions, it is judged that atrial fibrillation may have occurred. It is characterized by:

[0018] In the electronic blood pressure monitor of this embodiment, the determination unit calculates the average value of the pulse wave interval for each of the data groups for each measurement time, and determines whether or not data of the irregular pulse wave is present in the data group, and obtains an individual determination result as to whether or not an irregular pulse wave has occurred for each measurement time. Furthermore, the determination unit determines that atrial fibrillation may have occurred only when the individual determination result indicating that the irregular pulse wave has occurred is obtained for two or more of the three measurement times. This makes it possible to determine whether or not atrial fibrillation may have occurred using a simple algorithm.

[0019]

[0020]

[0021]

[0022] In one embodiment, the electronic blood pressure monitor comprises: a storage unit that stores the individual judgment result for each measurement opportunity in association with a measurement date and time; The judgment unit searches the individual judgment results stored in the memory unit, starting from the most recent one, and judges whether or not atrial fibrillation may have occurred only when the individual judgment results for the three or more measurement occasions are available and the condition that the time interval between the measurement occasions is within the allowable period is met.

[0023] In the electronic blood pressure monitor of this embodiment, the storage unit stores the individual judgment result for each measurement occasion in association with the measurement date and time. The judgment unit searches the individual judgment results stored in the storage unit from the latest one backwards, and judges whether or not atrial fibrillation may have occurred only when the individual judgment results for the three or more measurement occasions satisfy the condition that the time interval between the measurement occasions is within the allowable period. In other words, an old individual judgment result in which the time interval between the measurement occasions exceeds the allowable period is not used as the basis for judgment by the judgment unit. Therefore, the reliability of the judgment can be improved.

[0024] In one embodiment, the electronic blood pressure monitor comprises: a normal blood pressure measurement mode in which blood pressure measurement is performed only once per measurement opportunity by the cuff pressure control unit, the pressure detection unit, and the blood pressure measurement unit, and an atrial fibrillation screening mode in which blood pressure measurement is repeated three or more times per measurement opportunity, In the normal blood pressure measurement mode, the determination unit determines whether or not the irregular pulse wave data in the collected data group representing the pulse wave intervals satisfies a predetermined frequency condition; The device is characterized by comprising a notification unit that issues a notification to encourage switching from the normal blood pressure measurement mode to the atrial fibrillation screening mode when the frequent occurrence condition is satisfied.

[0025] The "predetermined frequent conditions" are as follows: i) A condition that one or more pieces of data on the irregular pulse wave are present in each of the data groups representing the pulse wave intervals for the most recent two measurement occasions; ii) A majority of the data groups representing the pulse wave intervals for the most recent five measurement occasions (i.e., data groups for three or more measurement occasions) each contain one or more pieces of data representing the irregular pulse wave. iii) A condition that one or more pieces of data on the irregular pulse wave are present in each of the data groups representing the pulse wave intervals for the two most recent measurement occasions at the same time of day (morning, afternoon, evening, etc.) every day; iv) The majority of the data groups representing the above pulse wave intervals for the most recent five measurement occasions taken at the same time each day (morning, afternoon, evening, etc.) (i.e., data groups for three or more measurement occasions) each contain one or more pieces of data showing the above irregular pulse wave. etc.

[0026] In the electronic blood pressure monitor of this embodiment, the cuff pressure control unit, the pressure detection unit, and the blood pressure measurement unit perform a normal blood pressure measurement mode by default, in which blood pressure is measured only once per measurement opportunity. In the normal blood pressure measurement mode, the determination unit determines whether the irregular pulse wave data in the collected data group representing the pulse wave intervals satisfies a predetermined frequent occurrence condition. When the frequent occurrence condition is satisfied, the notification unit issues a notification to urge the user to switch from the normal blood pressure measurement mode to the atrial fibrillation screening mode. This notification urges the user (including the subject, medical personnel such as a doctor and a nurse; the same applies below) to switch from the normal blood pressure measurement mode to the atrial fibrillation screening mode. If the atrial fibrillation screening mode can be switched to, screening for atrial fibrillation can be performed more accurately than in the normal blood pressure measurement mode.

[0027] In one embodiment, the electronic blood pressure monitor comprises: a normal blood pressure measurement mode in which blood pressure measurement is performed only once per measurement opportunity by the cuff pressure control unit, the pressure detection unit, and the blood pressure measurement unit, and an atrial fibrillation screening mode in which blood pressure measurement is repeated three or more times per measurement opportunity, In the normal blood pressure measurement mode, the determination unit determines whether or not the irregular pulse wave data in the collected data group representing the pulse wave intervals satisfies a predetermined frequency condition; The device is characterized by comprising a mode control unit that performs control to switch from the normal blood pressure measurement mode to the atrial fibrillation screening mode when the frequent occurrence condition is satisfied.

[0028] In the electronic blood pressure monitor of this embodiment, the cuff pressure control unit, the pressure detection unit, and the blood pressure measurement unit perform a normal blood pressure measurement mode by default, in which blood pressure measurement is performed only once per measurement opportunity. In the normal blood pressure measurement mode, the determination unit determines whether the irregular pulse wave data in the collected data group representing the pulse wave intervals satisfies a predetermined frequent occurrence condition. When the frequent occurrence condition is satisfied, the mode control unit performs control to switch from the normal blood pressure measurement mode to the atrial fibrillation screening mode. In the atrial fibrillation screening mode, blood pressure measurement is repeated three or more times per measurement opportunity. Therefore, in this atrial fibrillation screening mode, it is possible to more accurately determine whether or not there is a possibility that atrial fibrillation has occurred, compared to the normal blood pressure measurement mode.

[0029] Second In this aspect, Disclosure The method for determining atrial fibrillation using an electronic blood pressure monitor is as follows: 1. A method for determining atrial fibrillation in an electronic blood pressure meter that measures blood pressure based on an arterial pulse wave passing through a measurement site, comprising: The electronic blood pressure monitor is a cuff pressure control unit that controls the pressure of a cuff attached to a measurement site to be increased or decreased; a pressure detection unit that detects a cuff pressure signal representing the pressure of the cuff during a pressurization process or a depressurization process by the cuff pressure control unit; a blood pressure measuring unit that extracts a pulse wave signal representing a pulse wave superimposed on the cuff pressure signal and measures a blood pressure based on the pulse wave signal, The above-mentioned atrial fibrillation determination method includes the steps of: For each measurement occasion for a certain subject, a data group representing the pulse wave interval is obtained based on the pulse wave signal obtained only during one pressurization process or one depressurization process. Steps to be taken , The data group for three or more measurement occasions for the subject is compiled to obtain an average value of the pulse wave interval, and whether or not there is an irregular pulse wave data exceeding a predetermined allowable range with respect to the average value in the compiled data group is judged as to whether or not atrial fibrillation may have occurred. and The time intervals between the three measurement occasions are within a predefined tolerance period. It is characterized by:

[0030] this Disclosure According to the above-mentioned method for determining whether or not atrial fibrillation has occurred in an electronic blood pressure monitor, it is possible to determine with high accuracy whether or not there is a possibility that atrial fibrillation has occurred. In particular, since the time intervals between the three measurement occasions are within a predetermined allowable period, the reliability of the above determination can be improved. Moreover, since it is sufficient to perform one blood pressure measurement per measurement opportunity in order to determine whether or not there is a possibility that atrial fibrillation has occurred, the time required per measurement opportunity is relatively short. In a third aspect, the electronic blood pressure monitor of the present disclosure includes: An electronic blood pressure monitor for measuring blood pressure based on an arterial pulse wave passing through a measurement site, a cuff pressure control unit that controls the pressure of a cuff attached to a measurement site to be increased or decreased; a pressure detection unit that detects a cuff pressure signal representing the pressure of the cuff during a pressurization process or a depressurization process by the cuff pressure control unit; a blood pressure measuring unit that extracts a pulse wave signal representing the pulse wave superimposed on the cuff pressure signal and measures blood pressure based on the pulse wave signal; a pulse wave interval calculation unit for calculating a data set representing a pulse wave interval based on the pulse wave signal obtained during only one pressurization process or one depressurization process for each measurement occasion for a certain subject; a determination unit that calculates an average value of the pulse wave intervals by aggregating the data group for three or more measurement occasions of the subject, and determines whether or not atrial fibrillation may have occurred based on whether or not data of an irregular pulse wave that exceeds a predetermined allowable range with respect to the average value is present in the aggregated data group; Equipped with a normal blood pressure measurement mode in which blood pressure measurement is performed only once per measurement opportunity by the cuff pressure control unit, the pressure detection unit, and the blood pressure measurement unit, and an atrial fibrillation screening mode in which blood pressure measurement is repeated three or more times per measurement opportunity, In the normal blood pressure measurement mode, the determination unit determines whether or not the irregular pulse wave data in the collected data group representing the pulse wave intervals satisfies a predetermined frequency condition; The device is characterized by comprising a notification unit that issues a notification to encourage switching from the normal blood pressure measurement mode to the atrial fibrillation screening mode when the frequent occurrence condition is satisfied. In a fourth aspect, the electronic blood pressure monitor of the present disclosure includes: An electronic blood pressure monitor for measuring blood pressure based on an arterial pulse wave passing through a measurement site, a cuff pressure control unit that controls the pressure of a cuff attached to a measurement site to be increased or decreased; a pressure detection unit that detects a cuff pressure signal representing the pressure of the cuff during a pressurization process or a depressurization process by the cuff pressure control unit; a blood pressure measuring unit that extracts a pulse wave signal representing the pulse wave superimposed on the cuff pressure signal and measures blood pressure based on the pulse wave signal; a pulse wave interval calculation unit for calculating a data set representing a pulse wave interval based on the pulse wave signal obtained during only one pressurization process or one depressurization process for each measurement occasion for a certain subject; a determination unit that calculates an average value of the pulse wave intervals by aggregating the data group for three or more measurement occasions of the subject, and determines whether or not atrial fibrillation may have occurred based on whether or not data of an irregular pulse wave that exceeds a predetermined allowable range with respect to the average value is present in the aggregated data group; Equipped with a normal blood pressure measurement mode in which blood pressure measurement is performed only once per measurement opportunity by the cuff pressure control unit, the pressure detection unit, and the blood pressure measurement unit, and an atrial fibrillation screening mode in which blood pressure measurement is repeated three or more times per measurement opportunity, In the normal blood pressure measurement mode, the determination unit determines whether or not the irregular pulse wave data in the collected data group representing the pulse wave intervals satisfies a predetermined frequency condition; The device is characterized by comprising a mode control unit that performs control to switch from the normal blood pressure measurement mode to the atrial fibrillation screening mode when the frequent occurrence condition is satisfied. Effect of the Invention

[0031] As is apparent from the above, according to the electronic blood pressure monitor and the method for determining atrial fibrillation in an electronic blood pressure monitor disclosed herein, it is possible to accurately determine whether or not there is a possibility that atrial fibrillation has occurred in a relatively short time per measurement opportunity. [Brief description of the drawings]

[0032] [Figure 1] 1 is a block diagram showing the configuration of an electronic blood pressure monitor according to one embodiment of the present invention; [Diagram 2] Fig. 2(A) is a diagram showing a flow for determining whether or not atrial fibrillation may have occurred in a normal blood pressure measurement mode by the electronic blood pressure monitor. Fig. 2(B) is a diagram showing a process flow for searching in a memory for determination target data for determining whether or not atrial fibrillation may have occurred in the flow of Fig. 2(A). [Diagram 3] Fig. 3(A) is a diagram showing a flow of blood pressure measurement using the electronic blood pressure monitor. Fig. 3(B) is a diagram showing an example of a standard pulse wave interval. Fig. 3(C) is a diagram showing an example of a pulse wave interval in which an irregular pulse wave occurs. [Figure 4] Fig. 4(A) is a diagram illustrating an example of a screen displayed on the display when it is determined that there is a possibility that atrial fibrillation has occurred in the normal blood pressure measurement mode. Fig. 4(B) is a diagram illustrating an example of a screen displayed on the display when there is no possibility that atrial fibrillation has occurred (or information regarding atrial fibrillation) in the normal blood pressure measurement mode. [Diagram 5] Fig. 5(A) is a diagram illustrating an example of determination target data for a certain subject (patient A with atrial fibrillation) by a conventional method and a determination result as to whether or not atrial fibrillation may have occurred. Fig. 5(B) is a diagram illustrating an example of determination target data for the subject by the first embodiment of the present invention and a determination result as to whether or not atrial fibrillation may have occurred. [Figure 6] Fig. 6(A) is a diagram illustrating an example of the determination target data for another subject (atrial fibrillation patient B) by the conventional method and the determination result of whether or not atrial fibrillation may have occurred. Fig. 6(B) is a diagram illustrating an example of the determination target data for the subject by the first embodiment and the determination result of whether or not atrial fibrillation may have occurred. [Figure 7]Fig. 7(A) is a diagram illustrating the determination target data for yet another subject (healthy subject C) by the conventional method and the determination result as to whether or not atrial fibrillation may have occurred. Fig. 7(B) is a diagram illustrating the determination target data for that subject by the first embodiment and the determination result as to whether or not atrial fibrillation may have occurred. [Figure 8] FIG. 13 is a diagram for explaining a method for determining whether or not all the data to be determined are available, using other data to be determined about the subject (Mr. A, atrial fibrillation patient). [Figure 9] Fig. 9(A) is a diagram showing a flow for determining whether irregular pulse wave data of a subject satisfies a predetermined frequent occurrence condition in the normal blood pressure measurement mode. Fig. 9(B) is a diagram showing another flow for determining whether irregular pulse wave data of a subject satisfies a predetermined frequent occurrence condition in the normal blood pressure measurement mode. [Figure 10] FIG. 11 is a diagram showing a flow of an atrial fibrillation screening mode of the electronic blood pressure monitor. [Figure 11] Fig. 11(A) is a diagram illustrating an example of a screen displayed on the display when it is determined that the frequent occurrence condition is satisfied by the flow of Fig. 9(A). Fig. 11(B) is a diagram illustrating an example of a screen displayed on the display when it is determined that the frequent occurrence condition is satisfied by the flow of Fig. 9(B). [Figure 12] 10 is a diagram illustrating an example of data to be determined for a certain subject (patient A with atrial fibrillation) according to the flow of FIG. 9(A) or FIG. 9(B) and a determination result as to whether or not the frequent occurrence condition is satisfied. [Figure 13] FIG. 10 is a diagram illustrating another determination target data for the subject (patient A with atrial fibrillation) according to the flow of FIG. 9(A) or FIG. 9(B) and a determination result as to whether or not the frequent occurrence condition is satisfied. [Figure 14] FIG. 11 is a diagram showing the total time required per measurement opportunity when determining whether or not there is a possibility that atrial fibrillation has occurred using a conventional method. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0033] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

[0034] (Blood pressure monitor configuration) FIG. 1 is a diagram showing an electronic blood pressure monitor 1 according to an embodiment of the present invention. Block configuration This blood pressure monitor 1 is roughly divided into a blood pressure measurement cuff 20 that is attached around a rod-shaped measurement site (e.g., the upper arm) of the subject, and a main body 10 equipped with elements for measuring blood pressure.

[0035] The cuff 20 is a typical one, and is constructed by sandwiching a fluid bag 22 between an elongated strip-like outer cloth 21 and an inner cloth 23, and sewing or welding the peripheral edges of the outer cloth 21 and the inner cloth 23.

[0036] The main body 10 is equipped with a CPU (Central Processing Unit) 100 as a processor, a display 50, an operation unit 52, a memory 51 as a storage unit, a power supply unit 53, a pressure sensor 31, an oscillation circuit 310, a pump 32, a pump drive circuit 320, a valve 33, and a valve drive circuit 330. In this example, an air pipe 39a connected to the pressure sensor 31, an air pipe 39b connected to the pump 32, and an air pipe 39c connected to the valve 33 are joined together to form a single air pipe 39, which is connected to the fluid bag 22 in the cuff 20 so as to be capable of fluidly communicating therethrough. Hereinafter, the air pipes 39a, 39b, and 39c will be collectively referred to as the air pipe 39.

[0037] In this example, the display 50 is composed of an LCD (Liquid Crystal Display) and displays predetermined information according to a control signal from the CPU 100. In this example, the display 50 includes, from the top, a SYS display area 501 for displaying a systolic blood pressure SYS (Systolic Blood Pressure, unit: mmHg), a DIA display area 502 for displaying a diastolic blood pressure DIA (Diastolic Blood Pressure, unit: mmHg), a PLS display area 503 for displaying a pulse rate PLS (unit: beats / min), and an AF display area 504 for displaying information on atrial fibrillation for the subject, as illustrated in FIG. 4B. Note that, for convenience, the display areas 501, 502, 503, and 504 are illustrated with dashed frames in FIG. 4B, but the dashed frames are not actually displayed. The display 50 may be composed of an organic EL (Electro Luminescence) display, or may include an LED (Light Emitting Diode).

[0038] In this example, the operation unit 52 shown in FIG. 1 includes a measurement switch 52A for receiving instructions to start / stop blood pressure measurement, a memory switch 52B for calling up recorded results of blood pressure measurement, etc., and a mode changeover switch 52C for receiving instructions to switch between a normal blood pressure measurement mode and an atrial fibrillation screening mode, and inputs an operation signal according to a user's instruction to the CPU 100.

[0039] Here, "normal blood pressure measurement mode" refers to a mode in which blood pressure is measured only once per measurement opportunity, and it is determined whether or not atrial fibrillation may have occurred when all the data to be judged is collected. "Atrial fibrillation screening mode" refers to a mode in which blood pressure is measured three or more times per measurement opportunity, and it is determined whether or not atrial fibrillation may have occurred when all the data to be judged is collected.

[0040] The memory 51 stores data of a program for controlling the sphygmomanometer 1, setting data for setting various functions of the sphygmomanometer 1, data of blood pressure measurement results, etc. The memory 51 is also used as a work memory when the program is executed.

[0041] CPU 100 controls the overall operation of this sphygmomanometer 1 in accordance with a program for controlling sphygmomanometer 1 stored in memory 51. Specific control will be described later.

[0042] In this example, the pressure sensor 31 is a piezo-resistive semiconductor pressure sensor. This pressure sensor 31 outputs the pressure in the fluid bag 22 contained in the cuff 20 (called the "cuff pressure Pc") through an air pipe 39 as an electrical resistance due to the piezo-resistive effect. The oscillation circuit 310 oscillates at an oscillation frequency according to the electrical resistance from the pressure sensor 31. The CPU 100 obtains the cuff pressure Pc according to the oscillation frequency. The pressure sensor 31, the oscillation circuit 310, and the CPU 100 as a whole constitute a pressure detection unit that detects the pressure of the cuff 20. As will be described later, a pressure fluctuation component due to the pulse wave indicated by the measurement site (called the "pulse wave signal Pm") is superimposed on the cuff pressure Pc.

[0043] The pump 32 is driven by a pump drive circuit 320 based on a control signal given from the CPU 100, and supplies air to the fluid bag 22 contained in the cuff 20 through an air pipe 39. This increases the pressure of the fluid bag 22 (cuff pressure Pc). The valve 33 is a normally open type solenoid valve, and is driven by a valve drive circuit 330 based on a control signal given from the CPU 100, and opens and closes to discharge or seal air in the fluid bag 22 through the air pipe 39 and control the cuff pressure Pc. The pump 32, the pump drive circuit 320, the valve 33, the valve drive circuit 330, and the CPU 100 as a whole constitute a cuff pressure control unit that controls the increase or decrease of the cuff pressure Pc.

[0044] The power supply unit 53 supplies power to the CPU 100 , the display 50 , the memory 51 , the pressure sensor 31 , the pump 32 , the valve 33 , and other components within the main body 10 .

[0045] (First embodiment) 2A shows a flow for determining whether or not atrial fibrillation may have occurred in a normal blood pressure measurement mode by the CPU 100 of the blood pressure monitor 1. This flow corresponds to processing for one measurement occasion (including one blood pressure measurement) for a certain subject. In this example, the measurement occasions are assumed to be one in the morning (04:00 to 10:00), one in the afternoon (10:00 to 19:00), and one in the evening (19:00 to 02:00).

[0046] When the subject presses down the measurement switch 52A provided on the main body 10 with the cuff 20 attached to the part to be measured (step S101 in FIG. 2(A)), the CPU 100 first executes the blood pressure measurement process (step S102 in FIG. 2(A)).

[0047] Specifically, as shown in step S1 of Fig. 3(A), the CPU 100 first performs initialization. That is, the CPU 100 initializes the processing memory area, stops the pump 32, and adjusts the pressure sensor 31 to 0 mmHg (sets the atmospheric pressure to 0 mmHg) with the valve 33 open.

[0048] Next, the CPU 100 operates as a pressure control unit, closes the valve 33 (step S2), and drives the pump 32 to start pressurizing the cuff 20 (step S3). That is, the CPU 100 supplies air from the pump 32 to the fluid bag 22 contained in the cuff 20 through the air piping 39. At the same time, the CPU 100 operates as a pressure detection unit, detects the pressure (cuff pressure Pc) in the cuff 20 (fluid bag 22) through the air piping 39 with the pressure sensor 31, and controls the pressurization speed by the pump 32 based on the cuff pressure Pc. As a result, the cuff 20 is pressurized, and the artery passing through the measurement site is compressed. Here, the cuff pressure Pc detected by the pressure sensor 31 has a pressure fluctuation component (pulse wave signal Pm) due to the pulse wave superimposed thereon in addition to a smoothly changing component (DC component).

[0049] Next, when the cuff pressure Pc reaches a predetermined value (in this example, it is set to, for example, 200 mmHg so as to sufficiently exceed the subject's expected blood pressure value) (Yes in step S4), the CPU 100 stops the pump 32 (step S5).

[0050] Next, the CPU 100 operates as a pressure control unit and gradually opens the valve 33 (step S6). This reduces the cuff pressure Pc at a substantially constant rate. During this reduction process, the CPU 100 performs filtering to extract a pulse wave signal Pm from the cuff pressure Pc. Then, in step S7, the CPU 100 operates as a blood pressure measurement unit and attempts to calculate blood pressure values ​​(systolic blood pressure SYS (Systolic Blood Pressure) and diastolic blood pressure DIA (Diastolic Blood Pressure)) using a known oscillometric method based on the pulse wave signal Pm acquired at this time. The CPU 100 also calculates a pulse rate PLS [beats / min] based on the pulse wave signal Pm. Furthermore, the CPU 100 operates as a pulse wave interval calculation unit and obtains a data set representing a pulse wave interval (represented by "Δt") based on the pulse wave signal Pm for the current measurement occasion (in this first embodiment, the measurement occasion is synonymous with the measurement time). Furthermore, the CPU 100 functions as a judgment section, determining the average value of the pulse wave intervals (represented as "Δtave") for a data group representing the pulse wave interval Δt, and judging whether or not irregular pulse wave data is present in the data group.

[0051] In this example, as shown in FIG. 3B (a graph showing a pulse wave waveform with time t on the horizontal axis and pulse wave signal Pm on the vertical axis), the pulse wave interval Δt is defined as the peak-to-peak interval of the pulse wave Pw. An irregular pulse wave is a pulse wave that exceeds a predetermined allowable range (in this example, ±25%) for the average pulse wave interval Δtave. For example, in the pulse wave Pw1 shown in FIG. 3C, the interval Δt1 between the preceding adjacent pulse wave or the interval Δt2 between the succeeding adjacent pulse wave exceeds the allowable range of ±25% for the average pulse wave interval Δtave. Therefore, the pulse wave Pw1 is determined to be an irregular pulse wave.

[0052] In this example, the CPU 100 calculates the number of times an irregular pulse wave occurred in the data group for the current measurement occasion (referred to as the "number of irregular pulse wave occurrences n") as the individual judgment result. If the number of irregular pulse wave occurrences n is 0, it indicates that an irregular pulse wave did not occur for the current measurement occasion. If the number of irregular pulse wave occurrences n is 1 or more, it indicates that an irregular pulse wave occurred for the current measurement occasion.

[0053] If CPU 100 is still unable to calculate blood pressure values ​​SYS, DIA, pulse rate PLS, and number of occurrences of irregular pulse waves n due to insufficient data (NO in step S8 in FIG. 3A), it repeats the processes in steps S6 to S8 until the calculations are completed.

[0054] Once the blood pressure values ​​SYS, DIA, pulse rate PLS, and number of irregular pulse wave occurrences n have been calculated in this manner (Yes in step S8), the CPU 100 functions as a pressure control unit and performs control to open the valve 33 and rapidly exhaust the air in the cuff 20 (fluid bag 22) (step S9).

[0055] After that, in step S10 in FIG. 3A, the CPU 100 controls the display of the blood pressure values ​​SYS and DIA and the pulse rate PLS on the display 50. As a result, as shown in FIG. 4B, for example, the systolic blood pressure SYS=130 mmHg, the diastolic blood pressure DIA=72 mmHg, and the pulse rate PLS=66 beats / min are displayed in the SYS display area 501, the DIA display area 502, and the PLS display area 503 in the display 50, respectively. Note that in step S7 in FIG. 3A, since it has not yet been determined whether or not there is a possibility that atrial fibrillation has occurred, nothing is displayed in the AF display area 504. However, if the number of irregular pulse wave occurrences n for the current measurement opportunity is 1 or more, a mark, a message, or the like indicating that an "irregular pulse wave" has occurred may be displayed in the AF display area 504.

[0056] Furthermore, in step S10 in Fig. 3(A), the CPU 100 controls the measurement date and time, blood pressure values ​​SYS and DIA, pulse rate PLS, and number of occurrences of irregular pulse waves n for the current measurement occasion of the subject, in association with each other, to be stored in the memory 51. As a result, as shown in Fig. 5(B) as a table in the memory 51, for the current measurement occasion of the subject (in this example, atrial fibrillation patient A), the measurement date is stored as 09 / 22, the measurement time as 21:17, the blood pressure values ​​SYS and DIA and pulse rate PLS as 130 / 72 / 66, and the number of occurrences of irregular pulse waves as 0, in the first row (meaning the row immediately below the top of the table; the same applies below) of the table in Fig. 5(B), in this example. For simplicity, the units of the blood pressure values ​​SYS, DIA, and pulse rate PLS are omitted from the illustration, but as described above, the blood pressure values ​​SYS and DIA are in mmHg, and the pulse rate PLS is in beats / min (same below). In this way, one blood pressure measurement is performed per measurement opportunity. After this, the flow returns to that of FIG. 2(A).

[0057] In the above example, the blood pressure value, pulse rate PLS, and number of irregular pulse wave occurrences n were calculated during the depressurization process of the cuff 20 (fluid bag 22), but this is not limited to this and they may also be calculated during the pressurization process of the cuff 20 (fluid bag 22).

[0058] Next, in step S103 of FIG. 2(A), the CPU 100 functions as a judgment unit, searching the individual judgment results stored in the memory 51 backwards from the most recent one (the current measurement opportunity) to judge whether or not all the data to be judged is available.

[0059] Specifically, as shown in Fig. 2(B), it is determined whether there is data from the previous measurement opportunity within the allowable period (one day in this example) going back from the current measurement opportunity (step S131 in Fig. 2(B)), and if there is (Yes in step S131), it is further determined whether there is data from the measurement opportunity before last within the allowable period (one day in this example) going back from the previous measurement opportunity (step S132). If there is no data (No in step S131 or S132), the process of this normal blood pressure measurement mode is terminated.

[0060] For example, if the current measurement occasion corresponds to the first row in FIG. 5(B) (measurement date is 09 / 22, measurement time is 21:17) and there is no data from the previous measurement occasion (No in step S131), the processing of this normal blood pressure measurement mode is terminated.

[0061] At the next measurement opportunity, when the subject presses down the measurement switch 52A provided on the main unit 10 with the cuff 20 attached to the part to be measured (step S101 in FIG. 2A), the CPU 100 starts the blood pressure measurement process again (step S102 in FIG. 2A). As a result of this blood pressure measurement process, the following data is saved, as shown in the second row of FIG. 5B: the measurement date is 09 / 23, the measurement time is 08:39, the blood pressure values ​​SYS, DIA and pulse rate PLS are 124 / 78 / 76, and the number of irregular pulse wave occurrences n is 5. At this measurement opportunity, there is no data from the measurement opportunity before last (No in step S132), so the process of this normal blood pressure measurement mode ends.

[0062] Furthermore, when the subject presses the measurement switch 52A on the main body 10 with the cuff 20 attached to the measurement site at the next measurement opportunity (step S101 in FIG. 2A), the CPU 100 starts the blood pressure measurement process again (step S102 in FIG. 2A). As a result of this blood pressure measurement process, the following data is stored: the measurement date is 09 / 23, the measurement time is 16:14, the blood pressure values ​​SYS, DIA and pulse rate PLS are 117 / 72 / 59, and the number of irregular pulse wave occurrences n is 5, as shown in the third row in FIG. 5B. At this measurement opportunity, the individual judgment results (data on the number of irregular pulse wave occurrences n) D1 for three or more measurement opportunities are complete, satisfying the condition that the time interval between the measurement opportunities is within the above-mentioned allowable period (Yes in steps S131 and S132 in FIG. 2B). Therefore, the CPU 100 determines that the judgment target data D1 is complete (Yes in step S103 in FIG. 2A). The above allowable period may span multiple days as long as it is within one day.

[0063] At this time, the CPU 100 further works as a judgment unit and judges whether or not an individual judgment result (number of occurrences of irregular pulse waves n) indicating that an irregular pulse wave has occurred has been obtained for two or more of the three measurement occasions (step S104 in FIG. 2(A)). In the example of FIG. 5(B), irregular pulse waves are not generated (number of occurrences of irregular pulse waves n=0) for the first measurement occasion (the measurement occasion before last; measurement date is 09 / 22, measurement time is 21:17), irregular pulse waves are generated (number of occurrences of irregular pulse waves n=5) for the second measurement occasion (the previous measurement occasion; measurement date is 09 / 23, measurement time is 08:39), and irregular pulse waves are generated (number of occurrences of irregular pulse waves n=5) for the third measurement occasion (current measurement occasion; measurement date is 09 / 23, measurement time is 16:14). In this example, since irregular pulse waves are generated for two of the three measurement occasions, it is judged that there is a possibility that atrial fibrillation has occurred. For ease of understanding, the rightmost column in Fig. 5(B) shows the range of the determination data D1 and indicates the determination result "AF" that there is a possibility that atrial fibrillation has occurred. Note that the determination result that there is no possibility that atrial fibrillation has occurred is indicated as "Non-AF."

[0064] Next, the CPU 100 performs control to display information indicating that atrial fibrillation may have occurred on the display 50 in addition to the blood pressure values ​​SYS, DIA and pulse rate PLS for the current measurement opportunity. In this example, as shown in Fig. 4(A), a message saying "Atrial fibrillation may have occurred" is displayed in the AF display area 504 of the display 50. Note that instead of or in addition to the message, a mark indicating that atrial fibrillation may have occurred may be displayed.

[0065] After that, when the subject presses down the measurement switch 52A on the main body 10 while the cuff 20 is attached to the measurement site at the next measurement opportunity (step S101 in FIG. 2A), the CPU 100 starts the blood pressure measurement process again (step S102 in FIG. 2A). As a result of this blood pressure measurement process, the following data is stored: the measurement date is 09 / 23, the measurement time is 21:52, the blood pressure values ​​SYS, DIA and pulse rate PLS are 112 / 70 / 61, and the number of irregular pulse wave occurrences n is 3, as shown in the fourth row in FIG. 5B. In this case, in step S103 in FIG. 2A, it is determined that the determination target data D2 shown in the second to fourth rows in FIG. 5B is complete. In this example, since irregular pulse waves occur at all three measurement opportunities out of the three measurement opportunities, it is determined in step S104 in FIG. 2A that there is a possibility that atrial fibrillation has occurred.

[0066] Thereafter, as long as the subject repeats blood pressure measurements once in the morning, once in the afternoon, and once in the evening, it is determined whether or not there is a possibility that atrial fibrillation has occurred at each measurement opportunity.

[0067] In this case, the number of data on which the CPU 100 makes the above judgment is based is equal to or greater than the number of data from three consecutive blood pressure measurements in the conventional method. Therefore, this blood pressure monitor 1 can accurately determine whether or not atrial fibrillation has occurred. In addition, the possibility of atrial fibrillation occurring can be determined using a simple algorithm.

[0068] In addition, in this blood pressure monitor 1, since it is sufficient to perform one blood pressure measurement per measurement opportunity in order to determine whether or not there is a possibility that atrial fibrillation has occurred, the time required per measurement opportunity is relatively short. Note that blood pressure measurements may be performed multiple times per measurement opportunity.

[0069] In step S103 of FIG. 2(A), even if individual judgment results (data on the number of occurrences of irregular pulse waves n) for three or more measurement occasions are obtained, if the time interval between the measurement occasions is outside the above-mentioned allowable period (No in step S131 or S132 of FIG. 2(B), therefore No in step S103 of FIG. 2(A)), the CPU 100 does not judge whether or not atrial fibrillation may have occurred, and ends the processing of this normal blood pressure measurement mode. For example, in the first to third rows of the table of FIG. 8, irregular pulse waves have occurred for the three measurement occasions of the subject. or not The data D7 of the individual judgment results (number of occurrences of irregular pulse waves n) is obtained. Specifically, for the first measurement opportunity (the measurement opportunity before last; measurement date is 09 / 17, measurement time is 11:10), there is no irregular pulse wave (number of occurrences of irregular pulse waves n=0), for the second measurement opportunity (the previous measurement opportunity; measurement date is 09 / 20, measurement time is 08:36), there is no irregular pulse wave (number of occurrences of irregular pulse waves n=0), and for the third measurement opportunity (current measurement opportunity; measurement date is 09 / 21, measurement time is 07:40), there is an irregular pulse wave (number of occurrences of irregular pulse waves n=1). In this example, the period from the third measurement opportunity (current measurement opportunity) to the second measurement opportunity (previous measurement opportunity) is within one day, so it is within the allowable period (Yes in step S131 of FIG. 2(B)). However, since the measurement opportunity in the second row (the previous measurement opportunity) goes back more than two days from the measurement opportunity in the first row (the measurement opportunity before last), it is outside the allowable period (No in step S132 in FIG. 2(B), and therefore No in step S103 in FIG. 2(A). For this reason, a determination as to whether or not there is a possibility that atrial fibrillation has occurred (step S104 in FIG. 2(A)) is not made. This is indicated in the rightmost column in FIG. 8 as "D7; Outside allowable period."

[0070] In this way, an old individual judgment result (data on the number of occurrences of an irregular pulse wave n) in which the time interval between measurement opportunities exceeds the above-mentioned allowable period is not used as the basis for the above-mentioned judgment by the CPU 100. Therefore, the reliability of the judgment can be improved.

[0071] (Comparative verification between the conventional method and this invention) For example, FIG. 5(A) shows data when the subject (in this example, atrial fibrillation patient A) measured blood pressure three times consecutively per measurement occasion according to the conventional method. In this example, as shown in the first to third rows of the table in FIG. 5(A), blood pressure was measured three times consecutively at the measurement occasion in the 21:00 (night) on the measurement date 09 / 22. The number of irregular pulse wave occurrences n was 0 in the blood pressure measurements at the measurement times 21:17, 21:18, and 21:19. When these were used as the judgment target data and judged according to the conventional method (if there were two or more measurements in which an irregular pulse wave occurred at least once among three consecutive blood pressure measurements, it was judged that atrial fibrillation may have occurred), the judgment result "Non-AF" was obtained, indicating that atrial fibrillation may not have occurred. Next, as shown in the fourth to sixth rows in FIG. 5(A), blood pressure was measured three times consecutively at the measurement occasion in the 8:00 (morning) on ​​the measurement date 09 / 23. In the blood pressure measurements at 08:39, 08:40, and 08:42, the number of occurrences of irregular pulse waves n was 5, 2, and 7, respectively. When these were used as the data to be judged and judged according to the conventional method, the judgment result "AF" was obtained, indicating that atrial fibrillation may have occurred. Similarly, the judgment result "AF" was obtained for the measurement occasion at 16:00 (daytime) on the measurement date 09 / 23 shown in the 7th to 9th rows in Figure 5(A) that indicates that atrial fibrillation may have occurred. In addition, the judgment result "AF" was obtained for the measurement occasion at 21:00 (night) on the measurement date 09 / 23 shown in the 10th to 12th rows in Figure 5(A) that indicates that atrial fibrillation may have occurred. In this way, according to the conventional method, whether or not atrial fibrillation may have occurred is judged for each measurement occasion of the subject, so even for the data of atrial fibrillation patient A, the judgment result was divided into "Non-AF" and "AF" depending on the irregular pulse wave occurrence situation at the time of the measurement occasion. The reason for this is thought to be that even patients with atrial fibrillation do not experience the symptoms all the time, but may only experience the symptoms temporarily due to environmental factors such as drinking alcohol, stress, and lack of sleep.

[0072] The data of blood pressure values ​​SYS, DIA, pulse rate PLS, and number of occurrences of irregular pulse waves n for atrial fibrillation patient A in Fig. 5(B) used to explain the present invention (first embodiment) correspond to data extracted from the first blood pressure measurement among the measurement occasions in Fig. 5(A). Specifically, the data in the first row (measurement date 09 / 22, measurement time 21:17) of the data for the measurement date 09 / 22 (night) shown in the first to third rows in Fig. 5(A) is adopted as the data in the first row in Fig. 5(B). Also, the data in the fourth row (measurement date 09 / 23, measurement time 08:39) of the data for the measurement date 09 / 23 (morning) shown in the fourth to sixth rows in Fig. 5(A) is adopted as the data in the second row in Fig. 5(B). Similarly, the data in the seventh row (measurement date 09 / 23, measurement time 16:14) among the data for 16:00 (daytime) on the measurement date 09 / 23 shown in the seventh to ninth rows in Fig. 5(A) is adopted as the data in the third row in Fig. 5(B). Also, the data in the tenth row (measurement date 09 / 23, measurement time 21:52) among the data for 21:00 (night) on the measurement date 09 / 23 shown in the tenth to twelfth rows in Fig. 5(A) is adopted as the data in the fourth row in Fig. 5(B). As described above, according to the first embodiment, at the measurement occasion when the data in the third row in Fig. 5(B) (measurement date 09 / 23, measurement time 16:14) was obtained, the determination target data D1 was complete, and the determination result "AF" was obtained, indicating that atrial fibrillation may have occurred. 5B (measurement date 09 / 23, measurement time 21:52) was obtained, the judgment result "AF" was obtained, indicating that atrial fibrillation may have occurred. Thus, according to the first embodiment, it is determined that atrial fibrillation may have occurred only when individual judgment results indicating that irregular pulse waves have occurred are obtained for two or more of the three measurement occasions, and therefore, it is considered that the dependency on the irregular pulse wave occurrence status of a specific measurement occasion is mitigated compared to the conventional method, and as a result, a valid (highly accurate) judgment result was obtained regarding whether atrial fibrillation may have occurred.

[0073] FIG. 6(A) shows data when another subject (in this example, atrial fibrillation patient B) measured blood pressure three times consecutively per measurement occasion according to the conventional method. In this example, as shown in the first to third rows of the table in FIG. 6(A), blood pressure was measured three times consecutively at the measurement occasion in the 19:00 (night) on the measurement date 09 / 16. In the blood pressure measurements at the measurement times 19:32, 19:35, and 19:36, the number of irregular pulse wave occurrences n was 6, 2, and 3, respectively. When these were used as the judgment target data and judged according to the conventional method (if there were two or more measurements in which an irregular pulse wave occurred at least once among three consecutive blood pressure measurements, it was judged that atrial fibrillation may have occurred), the judgment result "AF" was obtained, indicating that atrial fibrillation may have occurred. Next, as shown in the fourth and fifth rows in FIG. 6(A), blood pressure was measured two times consecutively at the measurement occasion in the 6:00 (morning) on ​​the measurement date 09 / 17. In the blood pressure measurements at 06:08 and 06:11, the number of occurrences of irregular pulse waves n was 3 and 4, respectively. In this case, only two blood pressure measurements were taken, so the conventional method did not collect enough data to be judged, resulting in a result of "insufficient number of measurements." Next, as shown in the sixth to eighth rows in FIG. 6(A), blood pressure measurements were taken three times in succession at the measurement opportunity in the 12 o'clock hour (daytime) on the measurement date of 09 / 17. In the blood pressure measurements at the measurement times of 12:49, 12:50, and 12:51, the number of occurrences of irregular pulse waves n was 2, 4, and 6, respectively. When these were used as the judgment data and judged according to the conventional method, the judgment result "AF" was obtained, indicating that atrial fibrillation may have occurred. Similarly, the judgment result "AF" was obtained for the measurement opportunity in the 19:00 hour (night) on the measurement date of 09 / 17, shown in the ninth to eleventh rows in FIG. 6(A). Thus, according to the conventional method, if blood pressure measurements are taken less than three times for a certain measurement opportunity for the subject for some reason (such as the subject taking an incorrect number of measurements or a blood pressure monitor malfunction), the number of measurements is insufficient and a determination is not made as to whether or not atrial fibrillation may have occurred.

[0074] The data of blood pressure values ​​SYS, DIA, pulse rate PLS, and number of occurrences of irregular pulse waves n for atrial fibrillation patient B shown in Fig. 6(B) correspond to data extracted from the first blood pressure measurement among the measurement occasions in Fig. 6(A) in order to carry out the first embodiment of the present invention. Specifically, the data in the first row (measurement date 09 / 16, measurement time 19:32) of the data from 19:00 (night) on the measurement date 09 / 16 shown in the first to third rows of the table in Fig. 6(A) is adopted as the data in the first row of the table in Fig. 6(B). In addition, the data in the fourth row (measurement date 09 / 17, measurement time 06:08) of the data from 6:00 (morning) on ​​the measurement date 09 / 17 shown in the fourth and fifth rows in Fig. 6(A) is adopted as the data in the second row in Fig. 6(B). Similarly, the data in the sixth row (measurement date 09 / 17, measurement time 12:49) among the data for the measurement date 09 / 17 at 12:00 (daytime) shown in the sixth to eighth rows in Fig. 6(A) is adopted as the data in the third row in Fig. 6(B). Also, the data in the ninth row (measurement date 09 / 17, measurement time 19:35) among the data for the measurement date 09 / 17 at 19:00 (night) shown in the ninth to eleventh rows in Fig. 6(A) is adopted as the data in the fourth row in Fig. 6(B). According to the first embodiment, at the measurement occasion when the data in the third row in Fig. 6(B) (measurement date 09 / 17, measurement time 12:49) was obtained, the determination target data D3 was complete, and the determination result "AF" was obtained, indicating that atrial fibrillation may have occurred. In addition, at the measurement occasion where the data in the fourth row in FIG. 6B (measurement date 09 / 17, measurement time 19:35) was obtained, the judgment data D4 was collected, and the judgment result "AF" was obtained, indicating that atrial fibrillation may have occurred. As described above, according to the first embodiment, since only one blood pressure measurement data is used per measurement occasion, the judgment result "AF" was obtained at each measurement occasion from the measurement occasion in the third row (measurement date 09 / 17, measurement time 12:49) where the judgment data for atrial fibrillation patient B was collected. Therefore, according to the first embodiment, it is sufficient to perform one blood pressure measurement per measurement occasion when the subject wears the cuff 20 on the measurement site, so that it can be said that the number of measurements per measurement occasion is unlikely to be insufficient.

[0075] FIG. 7(A) shows data when another subject (in this example, a healthy subject C) measured blood pressure three times consecutively per measurement occasion according to the conventional method. In this example, as shown in the first to third rows of the table in FIG. 7(A), blood pressure was measured three times consecutively at the measurement occasion in the 4 o'clock (morning) on ​​the measurement date 08 / 01. In the blood pressure measurements at the measurement times 04:51, 04:52, and 04:53, the number of occurrences of irregular pulse waves n was all 0. When these were used as the judgment target data and judged according to the conventional method, the judgment result "Non-AF" was obtained, indicating that there was no possibility of atrial fibrillation occurring. Next, as shown in the fourth to sixth rows in FIG. 7(A), blood pressure was measured three times consecutively at the measurement occasion in the 13:00 (afternoon) on the measurement date 08 / 01. In the blood pressure measurements at the measurement times 13:35, 13:36, and 13:37, the number of occurrences of irregular pulse waves n was all 0. When these were used as the data to be determined and a determination was made according to the conventional method, a determination result of "Non-AF" was obtained, indicating that atrial fibrillation was not likely to have occurred. Similarly, a determination result of "Non-AF" was also obtained for the measurement opportunity at 22:00 (night) on the measurement date of 08 / 01 shown in the 7th to 9th rows in FIG. 7(A), indicating that atrial fibrillation was not likely to have occurred. Also, a determination result of "Non-AF" was obtained for the measurement opportunity at 5:00 (morning) on ​​the measurement date of 08 / 02 shown in the 10th to 12th rows in FIG. 7(A), indicating that atrial fibrillation was not likely to have occurred. In this way, according to the conventional method, a determination result of "Non-AF" was obtained for healthy subject C at each measurement opportunity, indicating that atrial fibrillation was not likely to have occurred.

[0076] The data of blood pressure values ​​SYS, DIA, pulse rate PLS, and number of occurrences of irregular pulse waves n for healthy subject C shown in Fig. 7(B) correspond to data extracted from the first blood pressure measurement among the measurement occasions in Fig. 7(A) in order to carry out the first embodiment of the present invention. Specifically, the data in the first row (measurement date 08 / 01, measurement time 04:51) of the data for 4:00 (morning) on ​​measurement date 08 / 01 shown in the first to third rows of the table in Fig. 7(A) is adopted as the data in the first row of the table in Fig. 7(B). In addition, the data in the fourth row (measurement date 08 / 01, measurement time 13:35) of the data for 13:00 (afternoon) on measurement date 08 / 01 shown in the fourth to sixth rows in Fig. 7(A) is adopted as the data in the second row in Fig. 7(B). Similarly, the data in the seventh row (measurement date 08 / 01, measurement time 22:53) among the data for the 22:00 (night) on the measurement date 08 / 01 shown in the seventh to ninth rows in Fig. 7(A) is adopted as the data in the third row in Fig. 7(B). Also, the data in the tenth row (measurement date 08 / 02, measurement time 05:00) among the data for the 5:00 (morning) on ​​the measurement date 08 / 02 shown in the tenth to twelfth rows in Fig. 7(A) is adopted as the data in the fourth row in Fig. 7(B). According to the first embodiment, at the measurement occasion when the data in the third row in Fig. 7(B) (measurement date 08 / 01, measurement time 22:53) was obtained, the determination target data D5 was complete, and the determination result "Non-AF" was obtained, indicating that there was no possibility of atrial fibrillation occurring. 6B (measurement date 08 / 02, measurement time 05:00), the judgment result "Non-AF" was obtained, indicating that there was no possibility of atrial fibrillation occurring, as the judgment target data D6 was complete. Thus, according to the above-mentioned first embodiment, for healthy subject C, from the measurement opportunity in the third row (measurement date 08 / 01, measurement time 22:53) when the judgment target data was complete, the judgment result "Non-AF" was obtained at each measurement opportunity, indicating that there was no possibility of atrial fibrillation occurring.

[0077] Thus, from the comparison of the judgment results in Fig. 5(A) with those in Fig. 5(B), the comparison of the judgment results in Fig. 6(A) with those in Fig. 6(B), and the comparison of the judgment results in Fig. 7(A) with those in Fig. 7(B), it was verified that according to the first embodiment of the present invention, it is possible to accurately determine whether or not there is a possibility that atrial fibrillation has occurred. Also, from the comparison of the judgment results in Fig. 6(A) with those in Fig. 6(B), it can be said that in the first embodiment of the present invention, since it is sufficient to perform one blood pressure measurement per measurement opportunity in which the subject once attaches the cuff 20 to the measurement site, a shortage of the number of measurements per measurement opportunity is unlikely to occur.

[0078] Regarding the condition that the time interval between measurement occasions is within the allowable period of "one day," it is not necessary to specify an exact numerical value; for example, it is sufficient that the time interval is within one day when rounded off to the nearest whole number (same below).

[0079] In the above example, the measurement occasions are assumed to be one in the morning (04:00-10:00), one in the afternoon (10:00-19:00), and one in the evening (19:00-02:00), but this is not limited to the above. For example, as shown in the fifth to seventh rows of the table in FIG. 8, three measurement occasions may be assumed, such as one in the morning of a certain day, one in the morning of the next day, and one in the morning after that. Specifically, the measurement occasion in the fifth row in FIG. 8 (measurement date 09 / 23, measurement time 08:39) corresponds to one in the morning of a certain day, and the number of occurrences of irregular pulse waves n is 5. The measurement occasion in the sixth row (measurement date 09 / 24, measurement time 08:16) corresponds to one in the morning of the next day, and the number of occurrences of irregular pulse waves n is 2. Also, the measurement opportunity in the seventh row (measurement date 09 / 25, measurement time 08:32) corresponds to one time in the morning of the day after, and the number of occurrences of irregular pulse waves n is 0. In this example, at the measurement opportunity in the seventh row (measurement date 09 / 25, measurement time 08:32), the determination target data D8 is complete, and a determination result "AF" is obtained indicating that atrial fibrillation may have occurred. In this way, in the above first embodiment, three measurement opportunities may be assumed, such as one time in the morning of one day, one time in the morning of the next day, and one time in the morning of the day after that.

[0080] In the above example, the data group obtained from three measurement occasions is used as the data to be judged, but this is not limiting, and a data group obtained from four or more measurement occasions may be used as the data to be judged.

[0081] In the above example, in step S7 in Fig. 3(A), an individual determination result that an irregular pulse wave occurred for each measurement occasion (number of occurrences of irregular pulse waves n) was obtained, but this is not limited to the above. A group of data representing pulse wave intervals for three or more measurement occasions of a subject may be collectively compiled to obtain an average value of the pulse wave intervals, and whether or not atrial fibrillation may have occurred may be determined based on whether or not data of an irregular pulse wave that exceeds a predetermined allowable range for the average value is present in the collectively compiled data group.

[0082] Second embodiment FIG. 9(A) shows a flow for determining whether or not irregular pulse wave data for a subject satisfies a predetermined frequent occurrence condition in the normal blood pressure measurement mode.

[0083] The "predetermined frequent conditions" are as follows: i) The condition that at least one irregular pulse wave data item is present in each of the data sets representing the pulse wave intervals for the most recent two measurement occasions; ii) A majority of the data groups representing pulse wave intervals for the most recent five measurement occasions (i.e., data groups for three or more measurement occasions) each contain one or more irregular pulse wave data points; iii) The condition that at least one irregular pulse wave data item is present in each of the data sets representing the pulse wave intervals for the two most recent measurement occasions taken at the same time each day (morning, afternoon, evening, etc.); iv) The majority of the data groups representing pulse wave intervals for the most recent five measurement occasions taken at the same time each day (morning, afternoon, evening, etc.) (i.e., data groups for three or more measurement occasions) each contain at least one irregular pulse wave. etc.

[0084] When the above frequency conditions i) and iii) are defined, the data to be judged must have individual judgment results (data on the number of times an irregular pulse wave occurs n) for two measurement occasions within the allowable period.When the above frequency conditions ii) and iv) are defined, the data to be judged must have individual judgment results for five measurement occasions within the allowable period.In this way, the number of measurement occasions for which individual judgment results must be defined as data to be judged is determined according to the predetermined frequency conditions.

[0085] In the first example, the frequent condition is the above condition i) "that one or more pieces of data on irregular pulse waves are present in each of the data groups for the most recent two measurement occasions."

[0086] When the subject (in this example, Mr. A, an atrial fibrillation patient) presses down on the measurement switch 52A provided on the main body 10 while the cuff 20 is attached to the part to be measured (FIG. 9 9(A) step S201), CPU 100 first executes a blood pressure measurement process (step S202 in FIG. 9(A)). In this step S202, similar to step S102 in FIG. 2(A), CPU 100 functions as a determination unit and calculates the number of occurrences n of irregular pulse waves as an individual determination result from a data group for the current measurement occasion (in this second embodiment, only in the normal blood pressure measurement mode, the measurement occasion is synonymous with the number of measurements).

[0087] For example, it is assumed here that the data in the first and second rows of the table in Fig. 12 have already been saved, and the data for the current measurement occasion is saved in the third row of the table in Fig. 12. Specifically, in the measurement occasion in the first row in Fig. 12 (the measurement occasion before last; measurement date 09 / 17, measurement time 11:10), the number of occurrences of irregular pulse waves n is 0. In the measurement occasion in the second row (the previous measurement occasion; measurement date 09 / 18, measurement time 21:41), the number of occurrences of irregular pulse waves n is 1. In the measurement occasion in the third row (current measurement occasion; measurement date 09 / 19, measurement time 17:09), the number of occurrences of irregular pulse waves n is 1.

[0088] Next, in step S203 in FIG. 9A, CPU 100 searches the individual judgment results stored in memory 51, going back from the most recent one (the current measurement opportunity), to determine whether or not all the judgment target data has been collected. In the example in the second and third rows in FIG. 12, individual judgment results (data on the number of occurrences of irregular pulse waves n) for two measurement opportunities are obtained. Therefore, CPU 100 determines that all the judgment target data D9 has been collected (Yes in step S203 in FIG. 9A). However, if all the judgment target data has not been collected (No in step S203), the process ends and the next measurement opportunity is awaited.

[0089] When the above-mentioned data to be determined are available, in step S204 in FIG. 9A, the CPU 100 functions as a determination unit and determines whether the irregular pulse wave data satisfies a predetermined frequent occurrence condition. In the example in the second and third rows in FIG. 12, the number of occurrences n of irregular pulse waves is 1 or more in the previous measurement occasion (measurement date 09 / 18, measurement time 21:41) and the current measurement occasion (measurement date 09 / 19, measurement time 17:09). Therefore, the CPU 100 determines that the above condition i) "that one or more pieces of irregular pulse wave data exist in each of the data groups representing the pulse wave intervals for the latest two measurement occasions" is satisfied (Yes in step S204 in FIG. 9A). For ease of understanding, the rightmost column in FIG. 12 shows the range of the data to be determined D9 and indicates the determination result "frequent irregular pulse wave occurrence" that the frequent occurrence condition is satisfied. If the frequent occurrence condition is not met (No in step S204), the process ends and the next measurement opportunity is awaited.

[0090] If the frequent occurrence condition is satisfied, in step S205 of FIG. 9A, the CPU 100 functions as a notification unit and issues a notification to encourage switching from the normal blood pressure measurement mode to the atrial fibrillation screening mode. For example, as shown in FIG. 11A, a message "Atrial fibrillation mode measurement is recommended" is displayed in the AF display area 504 of the display 50. This notification encourages the user (including subjects, doctors, nurses, and other medical personnel) to switch from the normal blood pressure measurement mode to the atrial fibrillation screening mode (described later). If the user switches to the atrial fibrillation screening mode using the mode change switch 52C (see FIG. 1), atrial fibrillation screening is performed with higher accuracy than in the normal blood pressure measurement mode. Instead of or in addition to the message, a mark encouraging switching to the atrial fibrillation screening mode may be displayed.

[0091] Alternatively, as shown in step S205' in Fig. 9(B), the CPU 100 may function as a mode control unit and perform control to switch from the normal blood pressure measurement mode to the atrial fibrillation screening mode. In this case, as shown in Fig. 11(B), for example, a message "Next time, measurement will be in atrial fibrillation mode" is displayed in the AF display area 504 of the display 50. Note that steps S201 to S204 in Fig. 9(B) are the same as steps S201 to S204 in Fig. 9(A).

[0092] 10 shows a flow of the atrial fibrillation screening mode by the CPU 100 of the sphygmomanometer 1. In the atrial fibrillation screening mode, it is planned to repeat blood pressure measurement three or more times per measurement opportunity.

[0093] When the subject presses down the measurement switch 52A provided on the main body 10 with the cuff 20 attached to the part to be measured (step S301 in FIG. 10), the CPU 100 starts the process in the atrial fibrillation screening mode.

[0094] In this atrial fibrillation screening mode, the CPU 100 first executes a blood pressure measurement process (step S302 in FIG. 10). This step S302 is the same as step S202 in FIG. 9(A) or FIG. 9(B) (specifically, steps S1 to S10 in FIG. 3(A)). As a result, for the current measurement in the current measurement opportunity of the subject, the measurement date and time, blood pressure values ​​SYS, DIA, pulse rate PLS, and the number of occurrences of irregular pulse waves n are stored in the memory 51 in a mutually associated manner.

[0095] 10, CPU 100 determines whether blood pressure measurement (step S302) has been performed a predetermined number of times (three times in this example). If blood pressure measurement has not been performed the predetermined number of times (No in step S303), the process is repeated until blood pressure measurement is performed. As a result, data on three consecutive blood pressure measurements for the current measurement occasion (i.e., the measurement date and time of blood pressure measurement, blood pressure values ​​SYS, DIA, pulse rate PLS, and number of occurrences of irregular pulse waves n) is stored in memory 51.

[0096] Next, as shown in step S304 of Fig. 10, CPU 100 uses the data of three consecutive blood pressure measurements stored in memory 51 as the data to be determined, and determines whether or not atrial fibrillation may have occurred, for example, by a conventional method. Specifically, if an irregular pulse wave occurred at least once in two or more measurements among three consecutive blood pressure measurements, it is determined that atrial fibrillation may have occurred. If an irregular pulse wave occurred at least once in one or less measurements, it is determined that atrial fibrillation may not have occurred.

[0097] Next, as shown in step S305 of Fig. 10, the CPU 100 performs control to display information indicating that atrial fibrillation may have occurred on the display 50 in addition to the blood pressure values ​​SYS, DIA and pulse rate PLS of the last measurement. For example, a message saying "Atrial fibrillation is possible" is displayed, similar to the display in the AF display area 504 in Fig. 4(A). Note that instead of or in addition to the message, a mark encouraging switching to the atrial fibrillation screening mode may be displayed.

[0098] In this way, in the atrial fibrillation screening mode, blood pressure measurements are repeated three or more times per measurement opportunity, and therefore, in this atrial fibrillation screening mode, it is possible to more accurately determine whether or not there is a possibility that atrial fibrillation has occurred, compared to the normal blood pressure measurement mode.

[0099] In the example of Fig. 10, the data group of three consecutive blood pressure measurements for the current measurement occasion is set as the determination target data, but this is not limited to this. A data group of four or more measurement occasions may be set as the determination target data.

[0100] (Variation 1) An example of adopting the above-mentioned frequent condition ii) "the condition that at least one irregular pulse wave data exists in the majority of the data groups representing the pulse wave intervals for the most recent five measurement occasions (i.e., the data groups for three or more measurement occasions)" will be described.

[0101] Looking at the fifth to ninth rows of the table in FIG. 12, in the fifth row (measurement date 09 / 21, measurement time 07:40), the number of occurrences of irregular pulse waves is 1. In the sixth row (measurement date 09 / 22, measurement time 07:50), the number of occurrences of irregular pulse waves is 0. In the seventh row (measurement date 09 / 23, measurement time 08:39), the number of occurrences of irregular pulse waves is 5. In the eighth row (measurement date 09 / 24, measurement time 08:16), the number of occurrences of irregular pulse waves is 2. In the ninth row (current measurement opportunity; measurement date 09 / 25, measurement time 08:32), the number of occurrences of irregular pulse waves is 0.

[0102] In this case, when data of the measurement occasion in the ninth row in FIG. 12 (current measurement occasion) is obtained, the CPU 100 judges that the judgment target data D10 is complete (Yes in step S203 in FIG. 9(A)). Then, in step S204 in FIG. 9(A), the CPU 100 functions as a judgment section and judges whether the irregular pulse wave data satisfies the frequent occurrence condition ii) above. In the example of the fifth to ninth rows in FIG. 12, the number of occurrences n of irregular pulse waves is 1 or more in three measurement occasions: the measurement occasion in the fifth row (measurement date 09 / 21, measurement time 07:40), the measurement occasion in the seventh row (measurement date 09 / 23, measurement time 08:39), and the measurement occasion in the eighth row (measurement date 09 / 24, measurement time 08:16). Therefore, CPU 100 determines that the above condition ii) "that at least one irregular pulse wave data item exists in the majority of the data groups representing the pulse wave intervals for the most recent five measurement occasions (i.e., data groups for three or more measurement occasions)" is satisfied (Yes in step S204 in FIG. 9(A)). For ease of understanding, the rightmost column in FIG. 12 shows the range of the judgment target data D10, as well as the judgment result "frequent occurrence of irregular pulse waves" that indicates that the frequent occurrence condition is satisfied. After this judgment, as described above, processing continues at step S205 in FIG. 9(A) or step S205' in FIG. 9(B).

[0103] (Variation 2) An example of adopting the above-mentioned iii) condition as the frequency condition, "that one or more irregular pulse wave data are present in each of the data groups representing the pulse wave intervals for the two most recent measurement occasions at the same time of day (morning, afternoon, evening, etc.) every day" will be described.

[0104] 13, the measurement dates 09 / 19, 09 / 20, ..., 09 / 25 are shown at the top of the table, and the measurement time periods "Morning (04:00-10:00)", "Afternoon (10:00-19:00)", and "Night (19:00-02:00)" are shown on the side. Each box on the table shows, from top to bottom, the measurement time (e.g., 08:07 in the top left box), the blood pressure values ​​SYS, DIA and pulse rate PLS obtained at that measurement time (e.g., 124 / 76 / 62 in the top left box), and the number of irregular pulse wave occurrences n (e.g., n=0 in the top left box). In this example, attention is focused on a measurement occasion during the daytime on the measurement date 09 / 23 (measurement date 09 / 23, measurement time 16:14) and a measurement occasion during the daytime on the measurement date 09 / 24 (measurement date 09 / 24, measurement time 15:06) in Fig. 13. The latter measurement occasion (measurement date 09 / 24, measurement time 15:06) is considered to be the current measurement occasion.

[0105] In this case, when data from the measurement opportunity during the daytime on the measurement date 09 / 24 (measurement date 09 / 24, measurement time 15:06) is obtained, the CPU 100 determines that the determination target data D11 is complete (Yes in step S203 in FIG. 9A). Then, in step S204 in FIG. 9A, the CPU 100 functions as a determination unit and determines whether the irregular pulse wave data satisfies the frequency condition iii) above. In the above example, the number of occurrences n of irregular pulse waves is 1 or more for both the measurement opportunity during the daytime on the measurement date 09 / 23 (measurement date 09 / 23, measurement time 16:14) and the measurement opportunity during the daytime on the measurement date 09 / 24 (measurement date 09 / 23, measurement time 15:06). Therefore, the CPU 100 determines that the above condition iii) "that at least one irregular pulse wave data item exists in each of the data groups representing the pulse wave intervals for the two most recent measurement occasions during the same time period (morning, afternoon, evening, etc.) every day" is satisfied (Yes in step S204 in FIG. 9(A)). For ease of understanding, the range of the data D11 to be judged is shown in the daytime period column in FIG. 13, along with the judgment result "frequent occurrence of irregular pulse waves" indicating that the frequent occurrence condition is satisfied. After this judgment, the process continues to step S205 in FIG. 9(A) or step S205' in FIG. 9(B) as described above.

[0106] (Variation 3) An example of adopting the above-mentioned iv) frequency condition, "the majority of data groups (i.e., data groups for three or more measurement occasions) representing pulse wave intervals for the most recent five measurement occasions at the same time each day (morning, afternoon, evening, etc.) contain at least one irregular pulse wave data item" will be described below.

[0107] In this example, attention is paid to the measurement occasion in the morning time slot on the measurement date 09 / 20 (measurement date 09 / 20, measurement time 08:36), the measurement occasion in the morning time slot on the measurement date 09 / 21 (measurement date 09 / 21, measurement time 07:40), the measurement occasion in the morning time slot on the measurement date 09 / 22 (measurement date 09 / 22, measurement time 07:50), the measurement occasion in the morning time slot on the measurement date 09 / 23 (measurement date 09 / 23, measurement time 08:39), and the measurement occasion in the morning time slot on the measurement date 09 / 24 (measurement date 09 / 24, measurement time 08:16) in Fig. 13. The measurement occasion in the morning time slot on the measurement date 09 / 24 (measurement date 09 / 24, measurement time 08:16) is assumed to be the current measurement occasion.

[0108] In this case, when data of the measurement occasion in the morning time slot of the measurement date 09 / 24 (measurement date 09 / 24, measurement time 08:16) is obtained, the CPU 100 judges that the judgment target data D12 is complete (Yes in step S203 in FIG. 9A). Then, in step S204 in FIG. 9A, the CPU 100 works as a judgment unit and judges whether the irregular pulse wave data satisfies the above-mentioned iv) frequent occurrence condition. In the above example, the irregular pulse wave occurrence count n is 1 or more in each of the three measurement occasions, namely the measurement occasion in the morning time slot of the measurement date 09 / 21 (measurement date 09 / 21, measurement time 07:40), the measurement occasion in the morning time slot of the measurement date 09 / 23 (measurement date 09 / 23, measurement time 08:39), and the measurement occasion in the morning time slot of the measurement date 09 / 24 (measurement date 09 / 24, measurement time 08:16). Therefore, the CPU 100 judges that the above condition iv) "that at least one irregular pulse wave data exists in the majority of the data groups (i.e., data groups for three or more measurement occasions) representing the pulse wave intervals for the most recent five measurement occasions in the same time period (morning, afternoon, evening, etc.) every day" is satisfied (Yes in step S204 in FIG. 9(A)). For ease of understanding, the range of the judgment target data D12 is shown in the morning time period column in FIG. 13, and the judgment result "frequent AF" indicating that the frequent occurrence condition is satisfied is also shown. After this judgment, the process of step S205 in FIG. 9(A) or step S205' in FIG. 9(B) continues as described above.

[0109] The above frequent occurrence conditions i) to iv) may be adopted individually, or alternatively, they may be used simultaneously in combination. In the case of combined use, when any of the above frequent occurrence conditions i) to iv) is satisfied in the current measurement opportunity, the CPU 100 determines that the irregular pulse wave data satisfies the frequent occurrence condition (Yes in step S204 in FIG. 9(A)). This allows for accurate determination of whether or not an irregular pulse wave occurs frequently.

[0110] Furthermore, the "predetermined frequent condition" in this second embodiment may be the condition described in relation to the first embodiment above that irregular pulse waves occur in two or more of three measurement occasions with one measurement per measurement occasion (number of irregular pulse wave occurrences n is 1 or more), in other words, the condition itself that data on the irregular pulse wave is present in a data group representing pulse wave intervals in two or more of three measurement occasions.

[0111] In the above example, the part to be measured is the upper arm, but this is not limited to this. The part to be measured may be an upper limb other than the upper arm, such as the wrist, or a lower limb, such as the ankle.

[0112] In the above example, the atrial fibrillation determination method according to the present invention is applied to a blood pressure monitor that measures blood pressure by the oscillometric method. However, the present invention is not limited to this, and the atrial fibrillation determination method according to the present invention can be applied to various types of electronic blood pressure monitors, such as blood pressure monitors that measure blood pressure by the tonometry method (a method in which blood vessels are pressed from above the skin so that they are partially flattened, and blood pressure is continuously measured for each beat based on a pulse wave signal).

[0113] The above-mentioned embodiments are merely examples, and various modifications are possible without departing from the scope of the present invention. The above-mentioned embodiments can be realized independently, but the embodiments can also be combined with each other. In addition, the various features of the different embodiments can be realized independently, but the features of the different embodiments can also be combined with each other. [Explanation of symbols]

[0114] 1. Blood pressure monitor 10 Main unit 20 Blood Pressure Cuff 31 Pressure Sensor 50 Display 51 Memory 52 Operation section 100 CPU

Claims

1. An electronic blood pressure monitor for measuring blood pressure based on an arterial pulse wave passing through a measurement site, a cuff pressure control unit that controls the pressure of a cuff attached to a measurement site to be increased or decreased; a pressure detection unit that detects a cuff pressure signal representing the pressure of the cuff during a pressurization process or a depressurization process by the cuff pressure control unit; a blood pressure measuring unit that extracts a pulse wave signal representing the pulse wave superimposed on the cuff pressure signal and measures blood pressure based on the pulse wave signal; a pulse wave interval calculation unit for calculating a data set representing a pulse wave interval based on the pulse wave signal obtained during only one pressurization process or one depressurization process for each measurement occasion for a certain subject; a determination unit that calculates an average value of the pulse wave intervals by aggregating the data group for three or more measurement occasions of the subject, and determines whether or not atrial fibrillation may have occurred based on whether or not data of an irregular pulse wave that exceeds a predetermined allowable range with respect to the average value is present in the aggregated data group; Equipped with The time intervals between the three measurement occasions are within a predefined tolerance period. An electronic blood pressure monitor characterized by:

2. 2. The electronic blood pressure monitor according to claim 1, The determination unit is calculating an average value of the pulse wave intervals for each of the data groups for each of the measurement occasions, and determining whether or not data of the irregular pulse wave is present in the data group, thereby obtaining an individual determination result indicating whether or not an irregular pulse wave has occurred for each of the measurement occasions; Only when the individual determination result that the irregular pulse wave occurred is obtained for two or more of the three measurement occasions, it is determined that there is a possibility that atrial fibrillation has occurred. An electronic blood pressure monitor characterized by:

3. 3. The electronic blood pressure monitor according to claim 2, a storage unit that stores the individual judgment result for each measurement opportunity in association with a measurement date and time; The electronic blood pressure monitor is characterized in that the judgment unit searches back from the most recent individual judgment results stored in the memory unit, and determines whether or not there is a possibility that atrial fibrillation has occurred only when the individual judgment results for three or more measurement occasions satisfy the condition that the time interval between measurement occasions is within the allowable period and are available.

4. 4. The electronic blood pressure monitor according to claim 1, a normal blood pressure measurement mode in which blood pressure measurement is performed only once per measurement opportunity by the cuff pressure control unit, the pressure detection unit, and the blood pressure measurement unit, and an atrial fibrillation screening mode in which blood pressure measurement is repeated three or more times per measurement opportunity, In the normal blood pressure measurement mode, the determination unit determines whether or not the irregular pulse wave data in the collected data group representing the pulse wave intervals satisfies a predetermined frequency condition; an alarm unit that issues an alarm to prompt the user to switch from the normal blood pressure measurement mode to the atrial fibrillation screening mode when the frequent occurrence condition is satisfied.

5. 4. The electronic blood pressure monitor according to claim 1, a normal blood pressure measurement mode in which blood pressure measurement is performed only once per measurement opportunity by the cuff pressure control unit, the pressure detection unit, and the blood pressure measurement unit, and an atrial fibrillation screening mode in which blood pressure measurement is repeated three or more times per measurement opportunity, In the normal blood pressure measurement mode, the determination unit determines whether or not the irregular pulse wave data in the collected data group representing the pulse wave intervals satisfies a predetermined frequency condition; a mode control unit that performs control to switch from the normal blood pressure measurement mode to the atrial fibrillation screening mode when the frequent occurrence condition is satisfied.

6. 1. A method for determining atrial fibrillation in an electronic blood pressure meter that measures blood pressure based on an arterial pulse wave passing through a measurement site, comprising: The electronic blood pressure monitor is a cuff pressure control unit that controls the pressure of a cuff attached to a measurement site to be increased or decreased; a pressure detection unit that detects a cuff pressure signal representing the pressure of the cuff during a pressurization process or a depressurization process by the cuff pressure control unit; a blood pressure measuring unit that extracts a pulse wave signal representing a pulse wave superimposed on the cuff pressure signal and measures a blood pressure based on the pulse wave signal, The above-mentioned atrial fibrillation determination method includes the steps of: determining a data set representing pulse wave intervals based on the pulse wave signals obtained during only one pressurization step or one depressurization step for each measurement occasion for a given subject; a step of aggregating the data group for three or more measurement occasions of the subject to obtain an average value of the pulse wave interval, and determining whether or not there is a possibility that atrial fibrillation has occurred based on whether or not there is data of an irregular pulse wave that exceeds a predetermined allowable range with respect to the average value in the aggregated data group, The time intervals between the three measurement occasions are within a predefined tolerance period.

11. A method for determining atrial fibrillation in an electronic blood pressure monitor.

7. An electronic blood pressure monitor for measuring blood pressure based on an arterial pulse wave passing through a measurement site, a cuff pressure control unit that controls the pressure of a cuff attached to a measurement site to be increased or decreased; a pressure detection unit that detects a cuff pressure signal representing the pressure of the cuff during a pressurization process or a depressurization process by the cuff pressure control unit; a blood pressure measuring unit that extracts a pulse wave signal representing the pulse wave superimposed on the cuff pressure signal and measures blood pressure based on the pulse wave signal; a pulse wave interval calculation unit for calculating a data set representing a pulse wave interval based on the pulse wave signal obtained during only one pressurization process or one depressurization process for each measurement occasion for a certain subject; a determination unit that calculates an average value of the pulse wave intervals by aggregating the data group for three or more measurement occasions of the subject, and determines whether or not atrial fibrillation may have occurred based on whether or not data of an irregular pulse wave that exceeds a predetermined allowable range with respect to the average value is present in the aggregated data group; Equipped with a normal blood pressure measurement mode in which blood pressure measurement is performed only once per measurement opportunity by the cuff pressure control unit, the pressure detection unit, and the blood pressure measurement unit, and an atrial fibrillation screening mode in which blood pressure measurement is repeated three or more times per measurement opportunity, In the normal blood pressure measurement mode, the determination unit determines whether or not the irregular pulse wave data in the collected data group representing the pulse wave intervals satisfies a predetermined frequency condition; an alarm unit that issues an alarm to prompt the user to switch from the normal blood pressure measurement mode to the atrial fibrillation screening mode when the frequent occurrence condition is satisfied.

8. An electronic blood pressure monitor for measuring blood pressure based on an arterial pulse wave passing through a measurement site, a cuff pressure control unit that controls the pressure of a cuff attached to a measurement site to be increased or decreased; a pressure detection unit that detects a cuff pressure signal representing the pressure of the cuff during a pressurization process or a depressurization process by the cuff pressure control unit; a blood pressure measuring unit that extracts a pulse wave signal representing the pulse wave superimposed on the cuff pressure signal and measures blood pressure based on the pulse wave signal; a pulse wave interval calculation unit for calculating a data set representing a pulse wave interval based on the pulse wave signal obtained during only one pressurization process or one depressurization process for each measurement occasion for a certain subject; a determination unit that calculates an average value of the pulse wave intervals by aggregating the data group for three or more measurement occasions of the subject, and determines whether or not atrial fibrillation may have occurred based on whether or not data of an irregular pulse wave that exceeds a predetermined allowable range with respect to the average value is present in the aggregated data group; Equipped with a normal blood pressure measurement mode in which blood pressure measurement is performed only once per measurement opportunity by the cuff pressure control unit, the pressure detection unit, and the blood pressure measurement unit, and an atrial fibrillation screening mode in which blood pressure measurement is repeated three or more times per measurement opportunity, In the normal blood pressure measurement mode, the determination unit determines whether or not the irregular pulse wave data in the collected data group representing the pulse wave intervals satisfies a predetermined frequency condition; a mode control unit that performs control to switch from the normal blood pressure measurement mode to the atrial fibrillation screening mode when the frequent occurrence condition is satisfied.

Images