Apparatus for generating information indicative of a heart condition

Abstract

To provide generation of information indicative of heart failure with reduced ejection fraction "HFrEF".SOLUTION: An apparatus for generating information indicative of heart failure with reduced ejection fraction (HFrEF) includes a signal interface (101) for receiving a signal indicative of cardiac angular rotation and a processing system (102) coupled to the signal interface. The processing system is configured to extract from the signal a temporal portion belonging to a diastolic phase of the heart. The processing system is configured to configure an output signal of the apparatus to represent the presence of heart failure with reduced ejection fraction based on a result of the comparison between the indicator quantity and the threshold value.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates generally to generating information indicative of heart failure with reduced ejection fraction "HFrEF." More particularly, the present disclosure relates to an apparatus for generating information indicative of HFrEF. Furthermore, the present disclosure relates to a computer program for generating information indicative of HFrEF. [Background technology]

[0002] Abnormalities that can occur within the cardiovascular system, if not diagnosed and appropriately treated and / or corrected, can progressively reduce the cardiovascular system's ability to maintain blood flow to meet the body's needs, especially when a person faces physical stress. For example, coronary flow reserve (CFR) is reduced not only by ischemic heart disease but also by heart failure (HF), an increasingly significant global health challenge that imposes significant economic and medical burdens due to high hospitalization, morbidity, and mortality rates. While HF is defined as a syndrome characterized by symptoms and physical examination findings, it can be further differentiated based on left ventricular ejection fraction (LVEF) and classified as HF with reduced ejection fraction (HFrEF), also known as systolic heart failure, and HF with preserved ejection fraction (HFpEF). While the clinical symptoms seen in HFpEF and HFrEF are similar, mortality rates differ, being lower in HFpEF than in HFrEF. In HFrEF, the heart muscle cannot contract adequately, and therefore less oxygen-rich blood is pumped into the body.

[0003] Currently, methods such as cardiography, echocardiography, and cardiac motion-based cardiography, which are based on electromagnetic phenomena related to cardiac activity, are used in the identification and assessment of various cardiac abnormalities. A well-known example of cardiography based on electromagnetic phenomena related to cardiac activity is electrocardiography (ECG), and examples of cardiac motion-based cardiography are gyrocardiography (GCG) and oscilloscope (SCG). Echocardiography is typically based on ultrasound and provides images of cardiac segments, which can provide extensive information about cardiac structure and function, but requires expensive equipment and specialized operating personnel. ECG provides a rapid electrical assessment of the heart but provides little information about the heart's structure. Oscilloscope-based cardiography is a noninvasive accelerometer-based method in which precordial vibrations of the heart are measured, while gyrocardiography is a noninvasive gyroscope-based method that measures cardiac angular rotation. As used herein, the term "gyroscope" encompasses various types of sensors for measuring angular rotation.

[0004] Heart failure with reduced ejection fraction (HFrEF), as described above, is relatively easy to detect using ultrasound-based echocardiography. However, there remains a need for a method of detecting HFrEF that can be implemented using commonly used consumer products, such as smartphones, that allows a user to perform an initial assessment of possible HFrEF at home and transmit the results to a health care system for review. Summary of the Invention

[0005] The following presents a simplified summary in order to provide a basic understanding of some aspects of various invention embodiments. The summary is not an extensive overview of the invention. It is not intended to identify key or critical elements of the invention or to delineate the scope of the invention. The following summary merely presents some concepts of the invention in a simplified form as a prelude to a more detailed description of example embodiments of the invention.

[0006] In accordance with the present invention, a novel apparatus is provided for generating information indicative of heart failure with reduced ejection fraction "HFrEF." The apparatus includes a signal interface for receiving a signal indicative of cardiac angular rotation and a processing system coupled to the signal interface. The processing system includes: extracting from the signal the time portion that corresponds to the diastolic phase of the heart; - forming an index quantity that indicates the energy of the time portion belonging to the diastole, - setting the output signal of the device to represent the presence of heart failure with reduced ejection fraction "HFrEF" based on the result of the comparison between the index quantity and a threshold value; It is structured as follows.

[0007] In light of empirical data, the above-mentioned index quantities indicating the above-mentioned energy related to diastole can be used as indicators of heart failure with reduced ejection fraction "HFrEF".

[0008] The thresholds mentioned above, which are compared to the index quantities, can be determined based on empirical data collected from groups of patients and healthy individuals. The thresholds are not necessarily constant; they may vary depending on the individual under consideration, over time, and / or on several other factors. Similarly, it is also possible to construct a series of thresholds, each representing a particular probability of HFrEF.

[0009] The device may include a sensor system for measuring a signal indicative of cardiac angular rotation. The sensor system may include a gyroscope for measuring cardiac angular rotation. Similarly, the sensor system may include an accelerometer for measuring cardiac acceleration in different directions, and the device may include a processor for computationally estimating cardiac angular rotation based on the accelerations measured in the different directions. Orientation determination mathematics using a three-axis accelerometer is presented, for example, by Pedley M.: Tilt Sensing Using a Three-Axis Accelerometer Freescale Semiconductor Application Note, Document Number: AN3461, Rev. 6, 03 / 2013.

[0010] A device according to an exemplary and non-limiting embodiment may be, for example, a smartphone or another handheld device that includes a gyroscope and / or an accelerometer, and may be placed on a person's chest to measure signals caused by heartbeat.

[0011] It should be pointed out that the signal interface of the device according to the exemplary and non-limiting embodiments may also be capable of receiving signals from an external device including a suitable sensor system, i.e., the device does not necessarily include means for measuring signals indicative of cardiac angular rotation.

[0012] According to the present invention, there is also provided a novel computer program for generating information indicative of a cardiac abnormality based on the above-described signals indicative of cardiac angular rotation, the computer program comprising: - extracting from said signal a time portion that corresponds to the diastole of the heart; - forming an index quantity that indicates the energy of the time portion belonging to the diastole, - setting an output signal to represent the presence of heart failure with reduced ejection fraction "HFrEF" based on the result of the comparison between the indicator quantity and a threshold value; The present invention includes computer executable instructions for controlling a programmable processing system to perform the above-described functions.

[0013] According to the present invention there is also provided a novel computer program product comprising a non-volatile computer readable medium, such as a compact disc "CD", encoded with a computer program according to the present invention.

[0014] The accompanying dependent claims set forth various exemplary, non-limiting embodiments.

[0015] The various embodiments, which are illustrative and non-limiting as to both structure and method of operation, together with additional objects and advantages thereof, can best be understood from the following description of specific illustrative embodiments when read in conjunction with the accompanying drawings.

[0016] The verbs "comprise" and "include" are used herein as open limitations that neither exclude nor require the presence of unrecited features.

[0017] The features recited in the accompanying dependent claims are freely combinable with one another unless expressly stated otherwise.

[0018] It is further to be understood that the use of "a" or "an", ie the singular, throughout this specification does not exclude a plurality.

[0019] Exemplary and non-limiting embodiments and their advantages are described in more detail below with reference to the accompanying drawings. [Brief explanation of the drawings]

[0020] [Figure 1] 1 shows a schematic diagram of an apparatus according to an exemplary and non-limiting embodiment for generating information indicative of heart failure with reduced ejection fraction "HFrEF." [Figure 2]1 shows true positive rate versus false positive rate curves associated with detecting heart failure with reduced ejection fraction "HFrEF" based on a signal indicative of cardiac angular rotation measured by a gyroscope and a signal indicative of cardiac acceleration measured by an accelerometer. DETAILED DESCRIPTION OF THE INVENTION

[0021] Specific examples provided in the following specification should not be deemed to limit the scope and / or applicability of the appended claims. Lists and groupings of examples provided in the specification are not exhaustive unless expressly stated otherwise.

[0022] 1 shows a schematic diagram of an exemplary, non-limiting apparatus 100 for generating information indicative of heart failure with reduced ejection fraction "HFrEF." The apparatus includes a signal interface 101 for receiving a signal indicative of cardiac angular rotation and a processing system 102 coupled to the signal interface 101. The processing system 102 includes: extracting from the signal the time portion that corresponds to the diastolic phase of the heart; - forming an index quantity that indicates the energy of the time portion belonging to the diastole, - setting an output signal of the device to represent the presence of HFrEF based on the result of the comparison between the indicator quantity and a threshold value; It is structured as follows.

[0023] The above-mentioned signals are generated using a sensor system 103 responsive to cardiac angular rotation. In the exemplary situation shown in FIG. 1 , the sensor system 103 is placed on the chest of a person 107. The sensor system 103 may include, for example, a gyroscope and / or an inertial measurement unit (IMU) including both an accelerometer and a gyroscope. The sensor system 103 may be, for example, a microelectromechanical system (MEMS). The gyroscope may be, for example, a Coriolis vibration gyroscope (CVG), which uses a vibrating structure to determine rotational speed. The temporal length of the signal measured using the sensor system may be, but is not necessarily, from tens of seconds to several hours. The output signal of the device may be, for example, a message displayed on a display screen of the user interface 104. The temporal portion belonging to the diastole can be recognized and extracted from the signal using any suitable known method, which may be based, for example, on known waveform complexes relating to systole and diastole.

[0024] In the exemplary case shown in Fig. 1, the sensor system 103 is connected to the signal interface 101 via one or more data transfer links, each of which may be, for example, a wireless link or a wired link. Data transfer from the sensor system 103 to the signal interface 101 occurs directly or via a data transfer network 105, for example, a telecommunications network. In the exemplary case shown in Fig. 1, the sensor system 103 is connected to a wireless transmitter. Similarly, it is also possible to integrate a device including a processing device 102 with the sensor system. In this exemplary case, the signal interface is a simple wire from the sensor system to the processing device. The device including the integrated sensor system may be, for example, a smartphone or another handheld device that can be placed on a person's chest during the measurement phase.

[0025] According to exemplary and non-limiting embodiments, the device is configured to record signals indicative of cardiac angular rotation. The recorded signals can be measured within a time window having a fixed temporal start point and a fixed temporal end point, or within a sliding time window having a fixed temporal length that moves over time. The device can include an internal memory 106 for recording the signals and / or can include a data port for connecting to an external memory.

[0026] There are many ways to generate an index quantity indicative of the energy associated with the diastolic phase of the cardiac cycle. formula:

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[0027] In the device according to an exemplary and non-limiting embodiment, processing system 102 is configured to maintain a series of thresholds, each threshold representing a particular probability of HFrEF, and processing system 102 is configured to set an output signal of the device to represent the probability of HFrEF based on the result of a comparison between the indicator quantity and the threshold.

[0028] The heart failure (HR) in both heart failure with reduced ejection fraction (HFrEF) and heart failure with preserved ejection fraction (HFpEF) is associated with an extra heart sound, the third heart sound S3, which occurs immediately after the two normal heart sounds S1 and S2, which are associated with the opening and closing of the aorta. The third heart sound S3 occurs approximately 0.12–0.18 seconds after S2, at the beginning of the middle third of diastole. The third heart sound S3 is thought to be caused by the oscillation of blood flow between the ventricular walls, initiated by the inflow of blood from the atria. The reason the third heart sound S3 does not occur until the middle third of diastole is probably because the ventricles do not fill sufficiently during the early part of diastole to create sufficient tension for reverberation. It may also be the result of tension in the chordae tendineae during rapid ventricular filling and expansion.

[0029] In an exemplary and non-limiting embodiment of the apparatus, the processing system 102 is configured to extract temporal portions from the signal such that the extracted temporal portions represent the middle third of the corresponding diastole.

[0030] The processing system 102 may be implemented, for example, with one or more processor circuits, each of which may be a programmable processor circuit with appropriate software, a special-purpose processor, e.g., an application specific integrated circuit "ASIC," or a configurable hardware processor, e.g., a field programmable gate array "FPGA," etc. The memory 106 may be implemented, for example, with one or more memory circuits, each of which may be, for example, a random access memory "RAM" device.

[0031] 2 shows curves 210 and 211 that represent the relationship between the true positive rate and the false positive rate. These curves 210 and 211 relate to the detection of heart failure with reduced ejection fraction (HFrEF) based on a signal indicative of cardiac angular rotation measured by a gyroscope. Curve 210 relates to the situation in which atrial fibrillation is present, and curve 210 relates to the situation in which atrial fibrillation is not present.

[0032] In the exemplary case relating to curves 210 and 211 in FIG. 2 , the gyroscope is a three-axis gyroscope, and the signal indicative of cardiac angular rotation has components indicative of rotation about the x, y, and z directions of a Cartesian coordinate system. The indicator quantity is calculated according to Equation 1 presented above, and a detection result is set to represent the presence of heart failure with reduced ejection fraction (HFrEF) in response to the indicator quantity exceeding a threshold. The true positive rate, also referred to as sensitivity, is the probability that an actual positive, i.e., the actual presence, of HFrEF is detected as a positive. The false positive rate is the probability that a false alarm is generated, i.e., the probability that a positive result is detected when the true value is negative, i.e., HFrEF is not present at all. If the aforementioned threshold is lowered, the true positive rate, i.e., the probability that the actual presence of HFrEF is detected as a positive, increases, but so does the false positive rate, i.e., the probability that a false alarm is generated.

[0033] FIG. 2 further illustrates curves 212 and 213 representing the relationship between the true positive rate and the false positive rate, with curve 212 relating to the presence of atrial fibrillation and curve 213 relating to the complete absence of atrial fibrillation. These curves 212 and 213 relate to the detection of heart failure with reduced ejection fraction (HFrEF) based on a signal indicative of cardiac acceleration measured using an accelerometer. In this illustrative example, the accelerometer is a triaxial accelerometer, and the signal indicative of cardiac acceleration has components indicative of acceleration in the x, y, and z directions of a Cartesian coordinate system. An indicator quantity is calculated in a manner corresponding to Equation 1 presented above, and a detection result is set to indicate the presence of heart failure with reduced ejection fraction (HFrEF) in response to the indicator quantity exceeding a threshold. If this threshold is lowered, the true positive rate, i.e., the probability that the actual presence of HFrEF will be detected as positive, increases, but so does the false positive rate, i.e., the probability that a false alarm will be generated.

[0034] As shown by Figure 2, HFrEF detection based on cardiac angular rotation measurements provides a significantly better true positive rate with a lower false positive rate than HFrEF detection based on cardiac acceleration measurements. Cardiac angular rotation measurements provide better detection results both in the presence of atrial fibrillation as well as in the complete absence of atrial fibrillation.

[0035] A computer program according to an exemplary and non-limiting embodiment includes a software module for generating information indicative of heart failure with reduced ejection fraction "HFrEF" based on a signal indicative of cardiac angular rotation. The software module includes: extracting from the signal the time portion that corresponds to the diastolic phase of the heart; - forming an index quantity that indicates the energy of the time portion belonging to the diastole, - setting an output signal to represent the presence of HFrEF based on the results of the comparison between the indicator quantity and a threshold value; The present invention includes computer executable instructions for controlling a programmable processing system for the purpose.

[0036] In the computer program according to an exemplary and non-limiting embodiment, a software module includes computer-executable instructions for controlling a programmable processing system to calculate an index quantity according to Equation 1 presented above.

[0037] In a computer program according to an exemplary and non-limiting embodiment, a software module includes computer-executable instructions for controlling a programmable processing system to extract temporal portions from a signal such that each extracted temporal portion represents the middle third of a corresponding diastole.

[0038] A software module may be, for example, a subroutine or function implemented using a suitable programming language and a suitable compiler for the programmable processing system and programming language under consideration. It is also worth noting that source code corresponding to a suitable programming language represents a computer-executable software module, since it contains the information needed to control a programmable processing system to perform the actions presented above, and compiling only changes the format of the information. Furthermore, a programmable processing system may be equipped with an interpreter, such that source code implemented using a suitable programming language does not need to be compiled prior to execution.

[0039] A computer program product according to an exemplary and non-limiting embodiment includes a computer readable medium, such as a compact disc "CD," encoded with a computer program according to one embodiment of the present invention.

[0040] In accordance with the exemplary and non-limiting embodiment, a signal is coded to carry information that defines a computer program in accordance with one embodiment of the present invention.

[0041] The specific examples provided in the foregoing description should not be deemed to limit the scope and / or applicability of the appended claims. The lists and groupings of examples provided in the foregoing description are not exhaustive unless expressly stated otherwise. [Configuration 1] - a signal interface (101) for receiving a signal indicative of cardiac angular rotation; a processing system (102) coupled to the signal interface, the processing system comprising: - extracting from said signal a time portion that corresponds to the diastole of the heart; - forming an index quantity indicative of the energy of said time portion belonging to said diastole; - based on the result of the comparison between the indicator quantity and a threshold value, setting an output signal of the device to represent the presence of heart failure with reduced ejection fraction. [Configuration 2] 10. The apparatus of claim 1, further comprising a sensor system (103) for generating the signal indicative of the cardiac angular rotation. [Configuration 3] 3. The apparatus of claim 2, wherein the sensor system includes a gyroscope for measuring the cardiac angular rotation. [Configuration 4] 4. The apparatus of configuration 3, wherein the gyroscope is a Coriolis vibratory gyroscope including a vibrating structure for determining rotational rate. [Configuration 5] The processing system comprises a processing system having a formula:

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Claims

1. a signal interface (101) for receiving a signal indicative of cardiac angular rotation; a processing system (102) coupled to said signal interface, the processing system comprising: extracting from said signal the time portion belonging to the diastole of the heart, forming an index quantity indicative of the energy of said time portion belonging to said diastole; - device (100), characterized in that it is adapted to set an output signal of said device so as to represent the presence of heart failure with reduced ejection fraction, based on the result of the comparison between said indicator quantity and a threshold value.

2. The apparatus of claim 1 , further comprising a sensor system (103) for generating the signal indicative of the cardiac angular rotation.

3. The device of claim 2 , wherein the sensor system includes a gyroscope for measuring the cardiac angular rotation.

4. 4. The apparatus of claim 3, wherein the gyroscope is a Coriolis vibratory gyroscope including a vibrating structure for determining rotational rate.

5. The processing system comprises a processing system having a formula: [Equation 1] where i is an index that increases over time, N is the number of samples in the time portion that belong to the diastole, and x i is the i-th cardiac rotation sample in the x direction of the Cartesian coordinate system (199), and y i is the i-th cardiac rotation sample in the y direction of the Cartesian coordinate system, and z i The apparatus of claim 1 , wherein i i is the i th cardiac rotation sample relative to the z direction of the Cartesian coordinate system.

6. 5. The apparatus of claim 1, wherein the processing system is configured to extract the temporal portions from the signal such that each extracted temporal portion represents a central third of the corresponding diastole.

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