TWI328442B - Detecting atrial fibrillation, method of and apparatus for - Google Patents

Description

</ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; The present invention generally relates to a method and apparatus for detecting atrial fibrillation by monitoring and analyzing a pulse, which uses an algorithm to eliminate abnormalities in the heart rhythm of atrial fibrillation. [Prior Art]

The heart is the main blood supply organ, which is the main pump that supplies blood through the body. The heart contains two upper chambers, the so-called atrium, and two lower chambers, called the ventricles. The right atrium receives hypoxic blood, while the left atrium receives oxygenated blood from the lungs. When the atrium is filled with blood, the outlet valve in the heart opens and the atrium squeezes blood into the ventricle. Then, the right ventricle injects hypoxic blood into the lungs, and the left ventricle injects the oxygenated blood to all parts of the body. In this way, the heart operates mainly like the same two-way pump. The regulator inside the heart, the so-called sinus node, signals every heart. This signal is emitted by the sinoatrial node in the right atrium, simultaneously; down to the interatrial septum to the atrioventricular node. This normal state is 'normal normal f-heart rhythm. The contraction of the ventricle is various, and it is various. Atrial fibrillation is abnormal in the heart rhythm - the transformation mode, the way of remnant contraction. * The mode of electrical activation of the room continues. The pulse of the room (4) is generated quickly and highly irregularly. It reaches the ventricle, and the ii, , and Q仃 filter functions only allow part of the pulse transmission mode, and the pattern of the earlier Hi is highly irregular. This irregular person: Analysis of ^ has not been tied to a bacterium pattern (Bootsma

Intervals in Patients with Atrial 5 1328442

Fibrillation at Rest and During Exercise. Circulation 41: 783, 1970). The term "irregular" as used in this application refers to a disorderly heartbeat pattern that is found only in atrial fibrillation. Atrial fibrillation is one of the most common types of medical care required for arrhythmia. Atrial fibrillation can be caused by a variety of cardiac conditions, such as angina, myocardial infarction, and high jk pressure. These conditions may cause the atrium to be pulled or injured&apos; and thus cause irregularities in the heart system. Atrial fibrillation may also be associated with lung problems or thyroid disorders&apos; and has severe morbidity and possibly fatality. Anyone, young and old, male or female, including visually impaired/visual blind people, may have atrial fibrillation. The occurrence of atrial fibrillation may be intermittent or habitual. The most common form of atrial fibrillation is the formation of a blood clot in the left atrium that may cause a stroke. However, many people with atrial fibrillation are not aware of their abnormal heart rhythm. Some people in the medical profession have therefore advocated self-testing of the pulse to detect possible atrial fibrillation. However, the disclosure of this document is generally limited to indicating how to self-detect the pulse of the individual and to make additional judgments in conjunction with descriptive information. The reason for using a pulse to detect atrial fibrillation is because the pulse is usually consistent with the heartbeat. The contraction of the left ventricle ejects gold into the aorta, and the resulting pressure wave is the pulse detected in the arterial system. However, when atrial fibrillation occurs, there is an irregular change in the time between heartbeats. When the time interval between heartbeats is long, blood can be injected into the ventricle for a longer period of time. Because of this heartbeat after this longer interval, the ventricles will eject more blood. A large amount of blood enters the active vein, causing the heartbeat systolic pressure to be higher. Conversely, 'when the time interval between heartbeats is short, the ventricle has only a short time to inject blood, because the heartbeat of 6 1328442 after this short interval is less blood jetted, causing the The secondary heartbeat systolic pressure is lower. In some cases, the time interval between heartbeats is too short, causing the systolic pressure of the subsequent heartbeat to be too low, so that the diagnosis cannot be diagnosed. This phenomenon of ventricular contraction, which cannot be diagnosed in the arterial system, is caused by the so-called "pulse shortness". This is quite common in atrial fibrillation. In the case of short pulse, the ventricular center hopping mode is irregular, but because of the shortest interval between heartbeats, it cannot be measured by pulse, so there will be less irregularities in the pulse mode. Therefore, the method of determining whether there is atrial fibrillation by analyzing the time interval of ventricular beats may not be equally effective when applied to the pulse.

Bert K. Bootsma, Adriann J. Hoelen, Jan Strackee and Frits L. Meijler et al., entitled Analysis of RR Intervals in Patients with Atrial Fibrillation at Rest and During Exercise, Circulation, Volume XLI, May 1970, describing the use The ECG analyzes the time interval between ventricular contractions. In this article, the mean value of the standard deviation divided by the interval of ventricular beats was evaluated in the normal state and atrial fibrillation. This article found that using this formula can accurately distinguish between atrial fibrillation and normal sinus rhythm. However, this is based on an electrocardiogram to determine ventricular contraction and cannot be applied to the pulse interval. Due to the short pulse of atrial fibrillation, the results determined by the ventricular contraction of the electrocardiogram cannot be applied to the time interval determined by analyzing the pulse. In particular, the degree of short pulse is determined by the method used to determine the pulse. If a method only detects a pulse with a high systolic pressure, then the number of pulses measured will be less than that measured by another method with higher sensitivity. The more sensitive the technology, the more pulse counts will be detected, but it may also cause more false positives.

7 For example, when using a finger probe and a light source and a photodetector, when the light volume is measured, if the sensitivity of the instrument is raised, even if the light is f, the finger is moved and detected. Bo. When the sensitivity of the instrument is set to the highest, the normal sinus rhythm is detected as an irregular pulse due to the miscellaneous force generated by the finger movement. When the sensitivity is set to the highest, the instrument is not suitable for home settings to detect atrial fibrillation. However, when the sensitivity is set to the lowest, only a few veins are detected. Therefore, any instrument or algorithm that wants to detect atrial fibrillation by pulse must be designed specifically for the purpose of detecting atrial fibrillation. In addition to this, there are many common heart rhythm abnormalities that do not increase the risk of stroke. For example, early-onset atrial contractions or early-onset heart-to-contraction can be found in many people, even in people without heart conditions. These occur intermittently, but are more common than atrial fibrillation and generally do not require treatment. Therefore, instruments designed to detect atrial fibrillation should include an algorithm that excludes detected early-onset heartbeats from irregular rhythms. If the instrument designed to detect atrial fibrillation is not able to eliminate the early onset of heartbeat, the number of false positives will be too high, and the practicality of the instrument will be greatly limited. People who often use the instrument to detect unexplained atrial fibrillation will quickly discard the instrument because most of the abnormal readings are from early onset heartbeat rather than atrial fibrillation. U.S. Patent No. 6,485,429 describes a method and apparatus for measuring arrhythmia using a vibrating blood pressure monitor. This patent discloses a method for measuring multiple heart rhythm abnormalities including upper ventricular contractions, early ventricular contractions, atrial fibrillation, paroxysmal upper heart rate, hyperphagy, and cardiac to rhythmia. A study done by the inventor of the patent using the patented commercial product found that the device only detected 66.6% of patients with atrial fibrillation, but detected 85.7% of early onset ventricular systolic 1328442 (Forstner KW, American Society of Hypertension 16th Annual Meeting 2003, page 25). Early onset ventricular contraction is much more common than atrial fibrillation. Therefore, when the intention is to detect only atrial fibrillation, if a device detects a very high proportion of early-onset ventricular contractions, but the proportion of atrial fibrillation detected is relatively low, the instrument is of little use. Other patents that detect abnormal heart rhythms, if used to detect atrial fibrillation, also produce a very high percentage of false positives. U.S. Patent No. 6, 〇95, 984 describes an embodiment (Part 1_2-1), and more than 0% of the pulse variations are considered abnormal. The most common arrhythmia, sinus arrhythmia, is defined by its definition (Braunwald, E. Heart Disease A textbook of Cardiovascular Medicine 1992, p 674), and the rate of heartbeat variability is over 10%. The algorithm of U.S. Patent No. 6,095,984 causes multiple sources of erroneous readings, and is not specifically designed to specifically detect the pulse of atrial fibrillation, so the method and apparatus of the patent cannot detect atrial fibrillation' and is not suitable for home monitoring of the atrium. Trembling. The algorithm for detecting atrial fibrillation by irregularities in the pulse interval should be designed to reduce the effects of early onset heartbeat. One method of reducing the impact of early onset heartbeat is to limit the number of beats used to determine the regularity of the pulse interval. For example, if the early onset of heartbeat occurs every 20 times, then limiting the analysis to only ten beats can reduce the likelihood that early onset heartbeat will occur during this analysis. This method was used in a lawsuit and published in PACE by Wiesel et al., 27=39-643 (2004). This method was used in this study to analyze 45 patients with a threshold of 0, of whom 54 were found to have atrial fibrillation. The study uses ~ algorithm to calculate an irregularity index, which is the standard deviation obtained by dividing the time interval between pulse bursts by the average time interval between pulse bursts. ^ 9 1328442 Analysis of only the automatic oscillatory blood pressure The last ten strokes recorded by the meter. If the index of all records exceeds G G6, it will be reduced to irregular. This study found that 1% of patients with atrial fibrillation were measured, and 16% of patients without atrial fibrillation also detected irregularities (1 sensitivity for atrial fibrillation was 100/. and specificity was 84%). Compared with the method used by F〇rstner, this method has made great progress in detecting the rate of atrial fibrillation.

Although the above limitation only analyzes the sensitivity table of the last ten pulse methods, it is excellent, but there is room for improvement in terms of specificity. Early-onset heartbeat is a heart rhythm abnormal towel. A common symptom that reduces the specificity of the index. For example, a premature ventricular premature heartbeat that occurs before a normal heartbeat will generate a pause after the heartbeat. Early onset heartbeat usually produces a lower pulse pressure than normal heartbeat. This early-onset heartbeat with low pulse pressure is often skipped by the sphygmomanometer and not recorded. Therefore, the early onset of heartbeat will result in a pause that is equal to the time interval between two normal heartbeats. If a patient has a heart rate of 60 beats per minute, the interval between normal heartbeats is one second. When the sphygmomanometer arm measures the early onset ventricular time, there is a two-second interval. The nine-second-second pulse interval and the two-second interval caused by early-onset Bo, the number is 0.29, far exceeding the threshold 〇.06. If the early onset of heartbeat occurs after G-5 seconds after the normal heartbeat, and is made by the domain meter, a long interval followed by a short interval will be formed. The eight-second interval, one 〇5-second interval, and one L5-second interval, the irregular index will still be quite abnormal. .24' and Joseph Wiesel's US Patent No. 6, 5, 9 49 露 disclose a method to remove the influence of the heartbeat by removing the pulse interval shorter than the average. This method improves the τ T two = pressure gauge to some extent (four) heterodyne. However, if there is a calculus = 10 out of the onset of early onset of heartbeat, and a longer interval, you can reduce the number of heartbeats that are shorter and detect the specific sound of atrial fibrillation. The ancient rate, and improved by the automatic sphygmomanometer, every interval - times will be; Heart = frequency-frequency interval If it is not the case between the average time, all the time Bo is because it falls within the average time ^, is shorter than it. If all is removed, the heart rhythm is removed because this mode is not the threshold of t. 4 tremors between the time 'so it will be treated as a small number of "=;: will \ = pressure gauge record for a period of time, may occur 0.5 seconds, respectively: f / and 0.85 seconds of early onset heartbeat If these intervals are more than .5 = except 'may still be caused by other intervals*, it is very high." Reduce the false positive value of early onset heartbeat patients' can use another ~ &amp; nasal method. In atrial fibrillation In the case, there will be no normal heartbeat. In the course of 10 to 40 seconds of a typical blood pressure measurement, there should be no more than half of the time interval is almost the same. On the other hand, even if there is frequent early onset Heartbeat, usually more than half of the heartbeats are normal $bo. Therefore, if a blood pressure measurement finds that most of the time = almost identical, it is highly likely that it is not atrial fibrillation. Household monitoring methods and equipment to detect the atrial fibrillation that can exist in the residual I, and to communicate this situation to the user, to remind the use of I to consult a professional physician for further testing ^ is a method, Can distinguish between atrial fibrillation and treatment. Pulse mode and common abnormality of the risk of serious sinus heart weight compared with helmets, such as the law of premature ventricular systolic heartbeat and ventricular early onset heartbeat. π Erli needs another method and equipment for In the period of time (4) (4) pulse rhythm and store the information for $ and

疋 a non-invasive, relatively 鲔I = method and device, which can be used to detect U

It trembles and is suitable for all ages and is accessible to people with impediments/disorders, and is relatively easy to use. The other is a 'monitoring method and device' that detects the presence of two pulses and displays and stores: i) the number of indirect irregular pulses at a predetermined time; and ii) within the selected interval , the period of continuity between the pulse. There is a need for a monitoring method and equipment, which can perform calculation or heuristic operation on the pulse data of U, and whether the pulse mode is irregular.

The pulse rhythm is compared. What you need to witness is what you need. It is a method and equipment that uses a sphygmomanometer to detect the pulse mode of the 3 and use it to make a heartbeat. What is just needed is a method and apparatus for detecting the presence of atrial fibrillation, which uses a plethysmograph such as a finger probe with a light source and photodetection to detect irregular pulse patterns. SUMMARY OF THE INVENTION The present invention provides a method and apparatus for determining the presence of atrial fibrillation by: (1) detecting a pulse interval 2 for a short period of time to determine whether the interval forms a disorder or irregularity. (ii) determining whether the pulse interval indicates possible atrial fibrillation, and then; (iii) communicating the information to the user so that they can seek advice from a professional physician to further (S) 12 steps for testing and treatment . This can be done at - time (4) = also provides a method and equipment for the purpose of providing the pulse and rhythm of the pulse and storing the pattern of the period of time and * for comparison. The present invention can also detect that the present invention further compares the modes of the simultaneous segments. By monitoring irregularities, non-invasive methods and devices, by storing and displaying information, such as -K, to detect atrial fibrillation. The number of possible inventions, and the irregularity of the selected interval k for a predetermined time interval may also be based on the duration between the correlations. Whether the rule pulse mode of the present invention exists.仃 calculus or heuristics to determine the monitoring of non-pulse, use the user's limbs such as the arm, inflatable armband, and wrap it around the beat. The time gate between the pulses is determined by the oscillation or auscultation device detecting the pulse. B w, the pulse interval can be detected when the arm band is deflated or stabilized, and the threshold is less than the minimum threshold. The invention allows the at least one or more pulses to be eliminated, and the early-onset heartbeat is prevented from being detected. And the necessary means to reduce the false positives of detecting atrial fibrillation. If the percentage of the pulse interval of 4 in a short period of time exceeds a percentage, the boundary value 'this invention can detect the normal sinus rhythm distributed between the abnormal pulse of a plurality of pulse interval changes, and detect the normal heart rhythm . Pulse monitoring can also be measured based on changes in light transmission between various limbs. Each time the pulse is changed, it will change the light passing through a part of the limb. The change in light transmission is consistent with the pulse, so the time interval between the pulses can be determined accordingly. Pulse monitoring can be performed using other plethysmographs, ultrasonic instruments that measure the arterial motion of each pulse, and ultrasonic waves that detect blood flow in the arteries. Use the above-mentioned "5" to detect the pulse of the invention, and the time between the pulse can be determined as one or more predetermined factors, including two to detect irregularity M#, . . . . . . . . . . . . . . , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , The invention uses the performance of Zengqi^r &amp; eight screens. Whether the beat is possible atrium: the child is:: to determine the irregular veins, the other details of the invention are as follows in the detailed description. Points, will refer to the relevant drawings [Embodiment] One of the inventions is actually implemented, and the gentleman detects the pulse. The versatile armband device is equipped with a vibrating auscultation device. It can be a known arm type. The armband instrument is placed around the limb, such as when the arm is stopped. The time of each pulse is transmitted to the genus. The (4) contains instructions to perform the method as described above. Each time of the pulse, the interval between the pulse and other information into the memory. The memory can contain RAM or other devices The memory contains a hard disk, a floppy disk or other device memory. The processor comprises a microprocessor and an application specific integrated circuit (ASIC), a programmable logic array (programmable logic array; plA) or reduced instruction set chip (RISC), the processor determines whether the mode of the pulse is directed to the atrium of 14 1328442 according to the pulse interval, and the processor then transmits the determination result to - and/or - audible generation Devices, etc. These instruments can display the pulsed material rules, money, possible cardiac motions, or should be used by the nurse, and can display other information, such as pulse number _. ~ Use oscillation in this embodiment The automatic blood-staining method for detecting pulse and blood pressure has been developed. In order to consider the short-pure and normal heartbeat systolic blood pressure at higher arm band pressure, it may be affected by respiratory variability.

&gt;, the impact of early-onset heartbeat, developed a set-up algorithm that only analyzes the last ten times of the pulse measured when the armband is pressed. Calculate the mean and standard deviation of the last ten pulses and determine the standard deviation divided by the average quotient. The resulting quotient is compared with a threshold of 0.06. If the quotient is greater than the threshold, then the mode of the pulse is determined to be irregular. As mentioned earlier, this method has been used in a lawsuit and published in Wiesel et al., pace 27:639-643 (2004), for 450 outpatients, 54 of whom developed atrial fibrillation. Atrial fibrillation was detected by one of the blood pressure readings of the method: sensitivity was 100% and specificity was 84%.

All pulse time intervals recorded by the instrument are used to determine an average time interval. If an irregular reading is found, one of two methods can be used to increase the specificity of atrial fibrillation (see Figures 3 and 4). In a first preferred method of the invention (Fig. 1), all of the intervals recorded by the automatic sphygmomanometer are used to determine an average time interval (see Figure 5). All intervals above 25% of the average, or 2% below the average, are excluded (see Figure 6). Calculate the remaining time interval and obtain a new average and standard deviation. Calculate the ratio of the new standard deviation to the new average, and calculate a new irregular index. If this irregularity means less than 0.066 ’, the heart rhythm rule is presumed. If the irregularity index is equal to or greater than 0.066, it is assumed that the heart rhythm is irregular and may be atrial fibrillation.

15 ^ In addition to high, below the threshold value _ after the interval, there is no remaining time A This mode is inconsistent with atrial fibrillation, but a typical early onset heartbeat every two occurrences, then this heart rhythm is a rule . Figure 1 is a schematic diagram of the flow of the method described in the section. Applying this algorithm to 247 irregular items in the previous study (Wl^Sel et al, PACE, 27:639-643 (2004)), all patients with atrial fibrillation are still detected as not Regular heart rhythm, but about half of patients who had previously measured irregular heart rhythm but not atrial fibrillation were reclassified as regular rhythms. This method increases the specificity to 92%' while maintaining sensitivity at 100%. In the second preferred method of the present invention (Fig. 2), all of the pulse time intervals recorded in the instrument are arranged from the shortest interval to the longest interval. Specifically, all time intervals recorded in the sphygmomanometer are arranged from the shortest interval to the longest interval (see Figures 7 and 8). Calculate the standard deviation of the first three time intervals starting with the shortest interval (see Figure 6). The ratio of the standard deviation to the mean is the irregular index of the three intervals. If the irregularity index is less than approximately 〇·01, it means that the three intervals are almost the same. The irregular index is then calculated with the three strokes after the shortest interval. And so on, until the irregular index of the longest three time intervals is calculated. If 50% or more than 50% of the irregularity index is less than about 0.01', the heart rhythm is a regular heart rhythm (see irregular heart rhythm of Fig. 9). Applying this algorithm to the 247 irregular readings in the previous study, all patients with atrial fibrillation still detected irregular heart rhythm, but the previously measured irregular readings were about three-thirds. The second was reclassified as a regular heart rhythm. The specificity of this method is 94% and the sensitivity is still maintained at 100%. Figure 2 is a schematic flow diagram of the method described herein. In another embodiment of the invention, the pulse is monitored by light changes through the limbs of the body, such as fingers. The light is emitted by a light source and passes through the finger or other limb of the subject through 1328442 and is received by a detector. The detector detects the pulse by changing the light transmitted through the limb. The detector can include a conventional pulse measuring instrument. The detector transmits the pulse time of each measurement to a processor. The processor executes the above operational procedures. The sensitivity of the detector can be adjusted in a conventional manner using a sensitivity detector of the light source detector to detect light from the source. When detecting a pulse, place your finger or other limb between the light source and the detector to activate the power source to emit light to reach the detector through your finger. It is an advantage of the present invention to provide a method and apparatus for easily detecting the presence of irregular heartbeats by a plurality of heartbeats, pulse trains, or other measurements. A further advantage is that the present invention distinguishes between atrial fibrillation rhythm and non-atrial fibrillation rhythm containing normal and abnormal heart rhythms. Yet a further advantage provides the invention with relatively simple and non-invasive home monitoring. The present invention comprises an apparatus and method comprising means for storing pulse intervals in a sequence from longest to shortest or shortest to long; means for calculating an irregular index I.sub.l of the first n time intervals, wherein The irregular index I. su b. 1 is the quotient of the mean and standard deviation of the first η time intervals; the irregular index I.sub.2 of the η time interval calculated from the second time interval is calculated. Apparatus, wherein the irregularity index I.sub.2 is a quotient of an average value and a standard deviation of the η time intervals from the second time interval; and a device for continuously calculating the irregularity index I.sub.m, Wherein m ranges from 1 to N-(nl), and η is the total number of pulse intervals; according to the irregular index I.sub.l, I.sub.2, ... I.sub.N-( What percentage of nl), P, is less than a threshold T, determines possible atrial fibrillation, and if Ρ exceeds a critical value of P.sub.cutoff, the rhythm shows 17 1328442

There is no atrial fibrillation, and if it is less than or equal to a critical value of P.sub.cutoff, the heart rhythm is atrial fibrillation. The present invention has been described in terms of the specific embodiments described above, but those skilled in the art should be able to make changes, modifications, and other uses. The invention is preferably limited to the scope of the following appended claims, and not to the extent of the disclosure. 18 1328442 [Simplified Schematic] Figure 1 is a flow chart of the algorithm (algorithm I) used to determine possible atrial fibrillation in the first method of the present invention. Figure 2 is a flow chart of the algorithm (algorithm II) used to determine possible atrial fibrillation in the second method of the present invention. Figure 3 is a graph showing the time interval of the sinus rhythm of the rule. Figure 4 is a graph showing the time interval of atrial fibrillation. Figure 5 is a graph showing the pulse time interval of sinus rhythm with early onset heartbeat, which is recorded before the application method I, which is recorded as a longer time interval. Figure 6 is a graph showing the resulting pulse time interval after the application of Method I in Figure 5. Figure 7 is a graph showing the time interval of pulsatile rhythm with frequent and varied early heartbeats recorded as longer and shorter intervals. Figure 8 is a graph showing the time interval obtained after the heart rhythm of Figure 7 is stored according to Method II. Figure 9 is a graph showing the pulse time interval of atrial fibrillation after storage according to Method II. [Main component symbol description]

19

Claims (1)

The scope of the patent application: 1 = use the method of calling the '^ axis, the method includes 2 steps: _ - a series of pulse Bo to provide a continuous time interval corresponding to the _ pulse; The continuous time = the average of one of the intervals, according to a certain percentage of the average, the root 2 consecutive time interval 'restandard deviation' where the continuous time 'only takes 4 or between the upper and lower limits Value, and the interval between the lower and lower upper limits is not counted, and the average is recalculated, and the calculated quotient is used to determine possible atrial fibrillation; if the quotient When the threshold is exceeded, the heart rhythm is determined to be atrial fibrillation. 2. A method for determining a heart rhythm that is not atrial fibrillation, the method comprising the steps of: detecting-continuous pulse to provide a continuous time interval corresponding to the series of pulses; determining the One of the continuous time intervals; according to a certain percentage of the average, the upper and lower limits are respectively determined; according to the continuous time interval, the average is recalculated and the standard deviation is calculated, wherein the continuous time interval is only Take a value equal to or between the upper and lower limits, and skip the time interval below the lower limit or above the upper limit; and divide the standard deviation by the recalculated average and calculate the quotient Compared with the -threshold, the possible atrial fibrillation is determined; if the quotient is less than the threshold, the heart rhythm is determined not to be atrial fibrillation. 3. The method of claim i, wherein the lower limit value is between about 0.50 and about 0.90 times the average value, and the upper limit value is 1.1 to 15 times the average value. door. 4. According to the method of applying for the scope of patents / wherein; the threshold is at &lt; S &gt; 20