Method for isolating st-segment of electrocardiosignal on-line and device for its implementation

FIELD: medicine, electrocardiography.

SUBSTANCE: the present innovation deals with measuring parameters of electrocardiosignal (ECS) ST-segment and their analysis to detect deviations against the norm. At every step of quantization one should form the readings of first-order differences and modules of first-order differences. One should memorize N of readings for the modules of first-order differences coming after ECS readings that correspond to the onset of cardiocycle. Then it is necessary to sum up memorized values of modules and at every step of quantization one should compare the obtained current sum value with previous one. It is necessary to memorize the greater of them and according to maximal value one should form threshold level to compare current value of modules sum. Time moments when sum value is at first greater and then lower against threshold level one should consider to be, correspondingly the onset and the end of ST-segment. Time segment between the onset and the end of ST-segment should be considered as duration of ECS ST-signal. Device to isolate ECS ST-signal on-line contains a block for forming ECS, a block for primary ECS processing, a quantization block, a block for isolating the point of cardiocycle onset and measurement of its duration, a block to form first-order differences, a block to form modules of first-order differences, a block to memorize readings for the modules of first-order differences, a block to detect the number of summarized readings for the modules of first-order differences, a summarizing block, a block to form a threshold level, a block for comparison and a key device. The innovation enables to isolate ST-segment more reliably for wider class of electrocardiograms at different modifications of QRS-complex form.

EFFECT: higher efficiency.

2 cl, 12 dwg

 

The invention relates to medicine, in particular to electrocardiography, and can be used for measuring parameters of ST-segment electrocardiogram (EX) and their analysis to detect deviations from the norm. The method implemented in the device, provides for increasing the reliability of the detection area of the cardiac cycle, belonging to the ST-segment.

In automatic estimation of parameters of the FORMER, in particular, in devices, Holter monitoring, one of the main tasks is to estimate the parameters of ST-segment changes of form which are diagnostic indicator of disorders of the cardiovascular system, in particular, coronary heart disease. The precondition for this diagnosis is accurate allocation of land to the FORMER belonging to the ST-segment.

There is a method implemented in the device [1], namely, that distinguish the R-wave, the time allocation of the R-wave mistaken for the beginning of the cardiac cycle (the anchor point), counts from him a specific time interval, to get to the ST-segment, and provide measurements of the displacement of the ST segment at this point, make a formation evaluation bias in the form of an integral over the lifetime of the ST-segment. These values are used to further evaluate the cardiovascular the th system.

The disadvantages of this method are:

1) fixed the duration of the time interval from the peak of the R-wave to the point made at the beginning of the ST segment that causes the error in the estimate of the location of ST-segment associated with changes in heart rate (HR) and variation of the shape of the QRS-complex. When you increase or decrease the heart rate, as well as the individual features of the FORMER point, taken as the beginning of the ST segment, may not coincide with its actual location. The anchor point of the beginning of the ST segment to the top of the R-wave when the modifications of the QRS-complex type QS, Qr, etc. leads to failures of the diagnostic algorithm;

2) fixed the duration of the interval of integration is taken over the duration of the ST segment, in most cases does not coincide with the actual duration, which reduces the accuracy of the estimation of its parameters.

Closest to the proposed method (prototype) is a method of allocating ST-segment [2], which consists in the fact that the signal amplify, filter, detect QRS-complex and allocate a reference point, adjust drift contours, exclude from the analysis is not typical for the patient in the form of abbreviations, average shape of the cardiac cycle at the interval specified duration, determine the coordinates of characteristic points of the cardiac cycle, with highlight to the ninety anchor points, located on the top of the R-wave, measure the duration of TRRcardiac cycle and the search start point ST-segment sliding moving window size of 10 milliseconds (MS) in the search area to the right of the anchor point. If this is the initial coordinate of the left border of the window select separated by 50 MS from the reference point. Compare the amplitude of the signal in the window with the specified threshold smoothness AFJ. If the amplitude a of the signal in the window exceeds a certain threshold smoothness AFJ, then the window is moved to the right to the position in which A<AFJ. The position of the left border of the window on the time axis is taken for the point JN the beginning of the ST segment. The duration of ST-segment counted from the point JN, determined by the formula:

TST=56 MS +0.05 TRR.

The disadvantages of this method are:

1) Snap the pivot to the top of the R-wave leads to the fact that when the variations of the QRS complex associated with diseases (splitting of the R-wave, the transformation of the QRS-complex in QS or Qr etc), possible errors in the allocation of the ST-segment.

2) the Occurrence of a lag data on the size of the moving window (at least). In relation to the allocation of ST-segment this means that information about the detection point JN will be received some time after its occurrence, which makes it impossible for the signal processing in real time and requires complicated procedures for estimating parameters of ST-is egment.

3) the Delay data associated with the process of averaging multiple cardiocycle.

The proposed allocation method ST-segment electrocardiograma in real time allows to eliminate the mentioned disadvantages of the prototype.

Analysis of the ECG as normal (shown in figure 1,a and 2,a), and with various deviations in the form of a QRS-complex, showed that the shape and amplitude of the QRS complex may be varied within considerable limits, until the disappearance of one of the teeth or, on the contrary, his cleavage. However, regardless of these factors, the main distinguishing feature of the QRS-complex from other areas of the FORMER, is the high rate of change of the signal level (increase or decrease)that is characterized by large values of the first derivative on the interval.

When sampling the EX-time analogue of the first derivative is the difference of the first order, i.e. the difference of the amplitudes of the next and previous samples. The authors found that when moving time window of duration equal to the duration of a QRS-complex of TQRSthat includes N discrete samples, along electrocardiograma, the sum of the moduli of the differences of the first order, for certain times, caught in the window, has a pronounced maximum at the end of the QRS-complex, i.e. at the point JN (figure 1,b).

Use the module the differences of the first order increases the rate of change of the signal amount in the area of a QRS-complex. Thus the influence on the shape of the curve of the sum of modules of the first derivative of other teeth (P, T, abnormal ST-segment), even a large amplitude can be neglected, as at least one order of magnitude lower. The influence of the noise component in the signal decreases due to the summation of signals in the time window. The resulting peak point can be considered as point JN the beginning of the ST segment.

Increasing the duration of the time window TWcompared with TQRSthe point of maximum turns into a "shelf" constant level of duration

TC=TW-TQRS,

aimed towards the ST segment, the beginning of which coincides with the point of JN the beginning of the ST segment, as shown in figure 2,B.

The known composition [3,4], linking the duration of the cardiac cycle (T), QT interval (TQT), QRS-complex (TQRSand ST segment (TST):

Based on these ratios, the total duration of the QRS complex and the ST segment will be

Thus, by setting the duration of the time window transformation TW=TQRS+STwill get:

TC=TW-TQRS,=TQRS+TST-TQRS,=TST.

In a time window of duration Twfit N sampling periods. Denoting the length of time increments in the organization Δ t get

In this case, the moment of reaching the maximum, corresponding to the beginning of the "shelves"coincides with a point JN the beginning of the ST segment, and the length of the plot of the maximum level ("shelves") equal to the estimated duration of the ST segment.

To exclude the effects of changes in the shape and amplitude of the QRS complex on the formation of reference points from which to begin moving a sliding window along the FORMER, as a reference point we can choose a point on the segment of the TR, which is known to correspond to the electrical diastole of the heart and the least susceptible to change shape [5].

The essence of the proposed method consists in the following. Electrocardiogram filter to eliminate interference from the mains 50 Hz, adjust the drift contours, eliminate from the analysis of atypical forms of abbreviations, discretizing time, allocate the anchor point to the beginning of each cardiac cycle and measure the duration T of the cardiac cycle. Then proposed the following sequence of actions. From each pair of successive samples of the FORMER form of the difference of the first order by subtracting from the value of the amplitude of the current reference amplitude value of the previous reference, then form the modules of the differences of the first order. Remember the values of the N samples of the modules of the differences of the first order, following th the reference the corresponding anchor point, while the number N is determined by the ratio

where T is the duration of the cardiac cycle;

Δt is the sampling period.

The time interval on which fit these N samples, the following period Δt, will be equal to the calculated value of TQRS+STi.e. the sum of the durations of the QRS-complex and ST-segment. The memorized values of the module of differentials of the first order, the number of which is N, summarize. Denote this sum as s On each of the next sampling exclude from the stored samples of the modules of the differences of the first order first closest to the beginning of the cardiac cycle count and add another newly formed countdown. For a new set stored samples also determine the sum of the moduli of the differences of the first order S.

Next to each regular sampling compares the current value of the sum of absolute difference of the first order with the previous and remember more of them, and in case of equality of the latter, Smaxthat is used for forming the threshold comparison. The value of Smaxis determined by the amplitude and shape of the QRS-complex of the analyzed cardiomegaly and may vary significantly for different patients, but varies only slightly within a single record ele is traitionally. Next, form a threshold level equal to (0.85-0.98)Smax. The study of a number of ECG with various modifications of the shape of the QRS-complexes showed that the lower limit threshold level is determined by the allowable error in the determination of the duration of ST-segment, and the upper bound on the precision of the elements that define a threshold level. For the practical implementation of the method is most suitable for forming the threshold level range from 0.85 Smaxto 0.9 Smax.

The current values of S sums of N samples of the modules of the differences of the first order at each step, the sample is compared with a threshold level. The point in time at which the value of S becomes equal to or exceeds the threshold level is taken as the beginning of JN ST-segment. The point in time at which the value of S, before exceeding the threshold level becomes equal to or less than the threshold, take the end of JK ST-segment. The time between the beginning of JN and end JK accept for the duration of ST-segment EX.

The proposed method allows a fair comparison with the known method (prototype)select ST-segment for a wider class of electrocardiograms with various modifications of the shape of the QRS-complex. When this signal is received about the presence of ST-segment coincides with the beginning that corresponds to the allocation of ST-segment in realhomemade.

The essence of the invention and possible options for implementation of the proposed method is illustrated in the following graphics:

- figure 3 is a structural diagram of a device that implements the proposed method;

- figure 4, figure 5 - implementation option unit 4 selection start point of the cardiac cycle and measuring its duration;

- 6 - embodiment unit 5 determine the number of summed samples module of differentials of the first order;

- 7 - version implementation of block 8 of storing samples of the modules of the differences of the first order;

- Fig - variant implementation of block 9 summation;

- figure 9 is an embodiment of the block 10 forming a threshold level;

- figure 10 is an embodiment of the key device 12;

- 11, peg - time diagrams explaining the operation of the device as a whole and some of its nodes.

To achieve the technical result consists in increasing the reliability of the allocation of ST-segment variations of the QRS-complex, the acceleration of the procedure of signal processing and ensuring the ability to provide the ST-segment in real time, and the implementation of the proposed method in a device that contains one United block forming electrocardiograma, block primary processing electrocardiograma made to perform amplification, filtering, correction of the drift of the contours and exclusions from the analysis of atypical forms of abbreviations, and block sampling, the first output of which is connected to the input of block selection start point of the cardiac cycle and measure its length, entered the block of formation of the difference of the first order, the processing unit modules of differences of the first order block memory timing modules of differences of the first order, the unit determining the number of summed samples module of differentials of the first order, the summation block, the block forming the threshold level, the unit of comparison and key device. The first output unit connected to the sampling input of the block forming the difference of the first order and to the first input key device, the second output unit sampling connected to the first input unit determining the number of summable discrete samples of the modules of the differences of the first order, a second input connected to the output of the block selection start point of the cardiac cycle and measuring its duration, and the output is connected to the first input of the summation block. The output processing unit difference of the first order is connected with the input of the processing unit modules of differences of the first order, the output of which is connected to the input unit storing samples of the modules to the difference of the first order, the output of which is connected with the second input of the summation block, the output of which is connected to the input of the shaping unit threshold level and the first in the Odom block comparison a second input connected to the output of the shaping unit threshold level, and the output is connected to a second input key device whose output is the output device.

The unit consists (figure 3) from block 1 forming electrocardiograma, unit 2 primary processing electrocardiograma, unit 3 sampling unit 4 selection of a reference point and measuring the duration of the cardiac cycle, block 5 determine the number of summable discrete samples of the modules of the differences of the first order, block 6 forming the difference of the first order, unit 7 forming modules of differences of the first order, block 8 memory timing modules of differences of the first order of summation block 9, block 10 forming a threshold level, block 11 comparison and key device 12.

Blocks 1, 2 and 3 are connected in series. The first output (signal) block 3 discretization is connected to the input unit 4 selection start point of the cardiac cycle and measuring its length and is connected also to the input of block 6 forming the difference of the first order and the first (signal) input key device 12, the second output (control) unit 3 sampling connected to the first input unit 5 determine the number of summed samples module of differentials of the first order, the output unit 4 selection start point of the cardiac cycle and measuring the duration for which geocycle connected with the second input unit 5 determine the number of summed samples module of differentials of the first order, the output of block 5 determine the number of summed samples module of differentials of the first order is connected with the first (Manager) the input of the summation block 9, the output of block 6 forming the difference of the first order is connected with the input unit 7 forming modules of differences of the first order, the output unit 7 forming modules of differences of the first order is connected with the input of block 8 of storing samples of the modules of the differences of the first order, the output unit 8 remember times connected with the second (signal) input of the summation block 9, the output of summation block 9 is connected to the input unit 10 forming the threshold level and the first input unit 11 of the comparison, the output of block 10 forming threshold level is connected with the second input unit 11 of the comparison, the output of block 11 comparison connected with the second (managing Director) key input device 12, the key device is the output device.

Unit 4 selection start point of the cardiac cycle and measuring its duration can be made on the basis of the device described in [5], according to the scheme given in figure 4. It contains a diagram of 13 double differentiation, two sources 14 and 15 threshold levels, the first level U1>0, and the second U2<0, the comparison circuit 16, the driver clock pulses 17, the first schema And 18, the first binary counter 19, the second scheme 20 scheme 21 conversion pulse point is achala cardiac cycle (reference points)in the pulse of "0" and "Write", the second binary counter 22 and a digital-to-analogue Converter (DAC) 25. Figure 5 shows an embodiment of the circuit of crawney 16 on the basis of two Comparators 24 and 25 and diagrams OR 26. The input circuit 13, which is the input unit 4 selection start point of the cardiac cycle and measure its length, is connected to the output of the block sample 3, with the input of the shaper clock pulses 17. The output of the circuit 13 double differentiation is connected with the first input of the comparison circuit 16, the second and third inputs of which are connected respectively to the outputs of source threshold levels 14 and 15. The output of the comparison circuit 16 is connected to the input R of zero binary counter 19 and to the first input of the first circuit And 18, the second input of which is connected to the output of the shaper clock pulses 17. The output of the circuit And 18 is connected to the input of the pulse. Bit outputs of the binary counter 19 is connected to the corresponding inputs of the second circuit 20, the output of which is connected to the input circuit 21 conversion of pulses of a reference point in pulses of "Recording" and "0", the first output of which is connected to the first input R (0) of the second binary counter 22, and the second output is connected to the first input (Recording) digital to analogue Converter 23. The second entrance (the Account) of the binary counter 22 is connected to the output of the shaper clock pulses 17 and the bit outputs of the counter 22 to connect the trading with the corresponding data inputs D of the DAC 23, the output which is the output of block 4. The comparison circuit 16 counts electrocardiograma with two threshold levels can be performed on two Comparators 24 and 25 and diagrams OR 26 (figure 5).

Unit 5 determine the number of summed samples module of differentials of the first order can be made on the basis of the device taking the square root [6] according to the scheme shown in Fig.6. It contains circuit 27 calculates square root of the ADC 28, the binary counter 29, scheme 30 scheme 31 comparison of two binary numbers, the inverter 32 and the generator 33 pulse Count. The input circuit 27 calculates square root of an input unit 5, and is connected to the output unit 4 for determining the point of beginning of the cardiac cycle and measuring its duration. The output of the circuit 27 is connected to analog input of the ADC 28, bit outputs of which are connected to the group of inputs of the comparison circuit 31, a group of inputs And which are connected with the bit outputs of the binary counter 29, which are, and the output unit 5. The output of the comparison circuit 31 is connected to the input of the inverter 32. The output of inverter 32 is connected to the first input of circuit 30, the second input of which is connected to the output of the generator 33 pulse Count. The output of the circuit And 30 connected to the first input (Expense) binary counter 29, the second input is R (0) is connected to the second output unit sampling 3.

One possible real the sale of block 8 of storing samples of the modules of the differences of the first order is shown in Fig.7. It consists of a shaper 34 pulse start, ADC 35 and the memory register 36. Analog ADC input 35 and the input of the shaper 34 pulse start interconnected and are input unit 8 memory timing modules of differences of the first order, which is connected to the output unit 7 forming modules of differences of the first order. Bit outputs of the ADC 35 is connected to the data inputs D of the memory register 36. The output of the ADC 35 "data availability" is connected to the input (Recording) memory register 36. Bit outputs of the register are output block 8 memory timing modules of differences of the first order.

The summation block 9, which forms at each step of sampling the amount of N modules of differences of the first order, may be made on the basis of accumulating adder [7] according to the scheme shown in Fig. It consists of a multiplexer 37, the summation 38, the first register 39 storing the current values of the sum, the second register 40 storing the sum of the values of N modules of differences of the first order shaper 41 pulses "Record 1" and "Record 2". The address inputs of multiplexer 37 (inputs) connected to the output unit 5 determine the number of summed samples module of differentials of the first order, and the data inputs (inputs D) - the output of block 8 of storing samples of the modules of the differences of the first order. The outputs of the multiplexer 37, the number of which is s is determined by the bit number, representing in binary form the values of the module of differentials of the first order, connected with a group of inputs And the summation circuit. The outputs of the summation circuit 38 is connected to the data inputs (D) of the first register 39, the outputs of which are connected with a group of inputs To the summation circuit 38 and with data inputs (D) a second register 40, bit outputs which are the output of the summation block 9. The input (Write) registers 39 and 40 are connected respectively with the first ("Record 1") and second ("Account 2") outputs of the pulse shaper 41.

A possible implementation of the block 10 forming the threshold level shown in Fig.9. The unit 10 includes a circuit storing the maximum value of the sum of N modules of differences of the first order, consisting of schematic comparison of binary numbers 42, scheme OR 43, a multiplexer binary numbers 44, the first register 45 storing the maximum value of the sum of N modules of differences of the first order and shaper 46 pulses of "Recording", and shaper threshold level, which can be made on the basis of the second register 47 in the formation threshold in digital form or on the basis of the DAC 48 and resistor divider 49 when forming the threshold level analog (analog variant shown by the dotted line in figure 9). The inputs of the group And of the comparison circuit 42, which is the input unit 10, is connected to the output side summing the Oia 9 and to the inputs of the group And of the multiplexer 44. The output "A>" of the comparison circuit 42 is connected to the enable input VA of the multiplexer 44. Outputs "And=" and "<" are connected respectively with the first and second inputs of the circuit OR 43, the output of which is connected to the enable input VB multiplexer 44.

The outputs of multiplexer 44 is connected to the data inputs (D) of the first register 45, the outputs of which are connected with inputs of the group In the comparison circuit 42 and a multiplexer 44 and with data inputs (D) a second register 47 or inputs of the DAC 48. The input (Write) registers 45 and 47 are connected respectively with the first ("Record 1") and second ("Account 2") outputs of the pulse shaper 46. The DAC output 48 is connected to the input resistive divider 49. If the threshold level is represented in digital form, the output of block 10 forming the threshold level are the outputs of the second register 47, and if in analog form of the output resistive divider 49.

The key device 12 can be implemented on the basis of the analog switches [8] according to the scheme shown in Fig. It contains the key element with the control circuit 50 and inverter 51. The first input is a key element 50, which is the first key input device 12, is connected to the first output of the block sampling 3. The second input is a key element 50 is connected to the output of the inverter 51, the inlet of which is the second input key of the element 12 and is connected to the output of the Comparer 11.

<> The device operates as follows. Block 1 forming electrocardiograma produces a signal is received from the patient's body. Unit 2 primary processing electrocardiograma performs the usual operations: enhance electrocardiogram, frees him from interference frequency filtering and eliminates drift contours using a high pass filter or by separating the signal drift contours using spline approximation with subsequent subtraction of the received signal from the source electrocardiograma [2]excludes from the analysis of atypical forms of abbreviations. Purified from interference EX (11, a) is fed to the input unit 3 sampling where it is converted into a set of discrete samples of the signal, with the following sampling period Δt.

From the first output unit 3 discrete samples EX fed to the input of block 4 selecting anchor points and measuring the duration of the cardiac cycle, the output of which is formed of pulse signals at points in time corresponding to the beginning of the cardiac cycle (11, b), and measured the intervals between them. The output signal of the block 4 are received at the first input unit 5 forming the N summed counts of modules of differences of the first order, which is controlled by clock pulses supplied to the second input unit from the second output unit 3 discr is a record with sampling period Δ t. In block 5 is calculated in accordance with expression (1) the number n As the number N determines the number of summable discrete samples of the modules of the differences of the first order, stored in the block memory 8, the output signals of the block 5 can be represented, for example, in a sequence of addresses of memory cells of the block 8, which reads the values mentioned timing modules of differences of the first order.

Also from the first output unit 3 discrete samples EX fed to the input of block 6, which counts cardiomegaly generates timing differences of the first order. Timing differences of the first order are converted to values of modules of differences of the first order in the block 7. From the output of the unit 7 counts the difference of the first order received in the block memory 8, is designed for memorization of M samples. The choice of M is of the conditions: M≥N.

In summation block 9 under the action of coming to the first output signal from the output of block 5 on each sampling are read-N of the M stored in the block of 8 samples of the modules of the differences of the first order and their summation. The output of summation block 9 is formed on each sampling signal amount S (11 in). The signal S is fed to the input unit 10 forming the threshold level and the first input unit 11 of the comparison, where the current value of S cf the W with a threshold level. In the shaping unit 10 threshold level of the first current sum value S is compared with the previous value and is remembered more important. If the next value of the sum S is less than or equal to the previous, stored previous value of s EX On the interval corresponding to the ST-segment, every regular value of the sum will be equal to the previous one and is equal to Smax(11). The maximum value of the sum of Smaxformed a threshold level of, as mentioned above, (0.85-0.98)Smax. From the output of block 10 forming a threshold level signal this threshold level is supplied to the second input of the comparison. The output of block 11 comparison during the overshoot signal's threshold level is generated pulse signal received at a control input key device 12 (11, g). The key device 12 opens and sends to the output of the device formed in the block sampling 3 discrete samples EX belonging to the ST-segment (figure 11, d shows the envelope of these samples). Next, the parameters of the selected ST-segment can be measured by any known method.

The following is a more detailed description of some blocks of the device.

Work unit 4 selection of a reference point of the beginning of the cardiac cycle and measuring its length (figure 4) consists in the following. Output unit the sampling 3 discrete counts electrocardiogram (EX), following with sampling period Δt, is fed to the input of the shaper differences of the second order 13, which is the input unit 4. The output of block 13 are signals of the differences of the second order, generated from three consecutive samples EX,

ddUi=Ui-2Ui-l+Ui-2,

where i is the number of samples involved in the formation of ordinary differential second order,

U is the amplitude of the corresponding reference.

The received signals of the differences of the second order are compared by the comparison circuit 16 with two threshold levels, one of which is positive +Unop (output of block 14), and the second negative-Uop (output of block 15). When the signal difference of the second order is between the threshold levels, the output signal of the comparison circuit 16 has a high potential level, which is fed to the input R of the counter 19, allowing his work in the counting mode, and one of the inputs of the first circuit And 18, allowing the passage at its output received at the other input of clock pulses from shaper 17. The repetition period of the clock pulses equal to the sampling period Δt electrocardiograma. Clock pulses from the output of the circuit And 18 arrive at the counting input of counter 19, which carries these impulses. The respective bit outputs of the counter 19 is connected to the corresponding inputs of the second circuit 20. With the persecuted anchor points (FROM pig) in the form of a rectangular pulse of positive polarity appears at the output of the second circuit And 20 only when the counter 19 will count Q of consecutive clock pulses. The output of circuit 20 is taken as a reference point in the cardiac cycle.

The number Q is chosen so that it could be achieved at the expense of consecutive clock pulses only on TR-segment electrocardiograma. On all other segments (PQ, ST) cardiomegaly timing differences of the second order will go beyond the threshold level before the counter 19 will count up to the number q at the output of the comparison circuit 16 will receive a low level signal, which sets the counter 19 to the input R to the zero state and prohibits the passage of clock pulses through the first circuit And 18. When the next input signal difference of the second order in the area between the threshold levels, the counter starts counting clock pulses from the beginning. Thus, at the output of the second circuit 20 is formed by a sequence of pulses (reference points in each cardiac cycle) (FROM pig), the distance between which determines the duration of the corresponding cardiac cycle T, which is in block 5 is converted to the number N of the aggregate counts of the modules of the differences of the first order, is proportional to.

Known typical analog devices [6], implement the operation to retrieve the rootwhere E is the coefficient proportionate the spine with the dimension [In]. Therefore, the duration of the cardiac cycle T should be expressed as proportional to the voltage U, which will be the input (UIfor device root extraction unit 5.

Because when you change T change the number located between the support points of the clock pulses, with the following sampling period Δt, then the transformation T is proportional to the voltage U is made on the basis of the binary counter and a digital to analogue Converter (DAC) (figure 4). Scheme 21 pulse shaping "Record" and "0" emit pulses FROM (Fig), respectively front and rear fronts (signal Recording and Mouth. 0 Fig). The pulse is "0", the counter 22 is set to the zero state, then the counter starts counting clock pulses located between adjacent FROM. At the end of each cardiac cycle pulse Write the contents of the counter 22 is moved into the input register d / a Converter 23. The voltage at the DAC output 23, which is the output of block 4, is proportional to the number regarded the counter 22 of clock pulses, i.e. the duration of the cardiac cycle T, and does not change during the next cardiac cycle.

Unit 5 determine the number of summable discrete samples of the modules of the differences of the first order (6) works as follows.

The number N is summable discrete reference is in the module of differentials of the first order is proportional to the square root of the duration of the cardiac cycle So In unit 4 the duration of the cardiac cycle T is represented as proportional voltage U. In the device 27 in the operation of taking the square root of the input signal UIwhich is proportional to the duration of the cardiac cycle So the Output signal 27 of the extraction of a square root is proportional to. Digital representation of this signaldevice root extraction 27 gives the number N indicates the number of values of modules of differences of the first order are summed in the summation block 9. The conversion signal Uobinary code is implemented using functionally complete ADC 28 (for example, type PW). Address N values of modules of differences of the first order, stored in the block 8 and subject to summation block 9 can be formed by using a binary counter 29 (6). The counter 29 is installed in the original zero state pulse of the Mouth. 0)coming from the second output unit 3 sampling with sampling period Δt. At the counting input of the counter 29 is transmitted through the scheme And 30 heartbeats (T) with period TT≤Δt/Nmaxfrom the output of the generator T 33. On the bit outputs of the counter 29, which is the output of block 5, code is generated addresses, the value of which increases by one when it arrives at midrange the private input of each clock pulse. Code each address is compared by the comparison circuit 31 with code number N, present at the output of the ADC during the next cardiac cycle. In case of equality of codes output "=" of the comparison circuit 31 is formed by a high signal, which is inverted by the inverter 32 and blocks the passage through the scheme And 30 clock pulses from the output of the pulse generator 33 to the counting input of the binary counter 31.

During the time between the installation of the counter 29 to "0" and the stop of the account when the number N bit outputs of the counter to the summation block 9 in turn issued address N samples of the modules of the differences of the first order, stored in the block memory 8, providing a summation latest within one sampling period. With the beginning of the next sampling period, the counter 29 (6) is reset and starts a new cycle address generation. In block 8 of storing samples of the modules of the differences of the first order when this occurs, the shift information in one step (see below), so the number of summed values of the module of differentials of the first order excluded the first and added another.

In block 8 of storing samples of the modules of the differences of the first order are memorizing M samples of the modules of the differences of the first order and the operation of the exceptions in each of the next sampling from among the stored samples of modularity first order nearest to the beginning of the cardiac cycle counting and adding another, the newly formed reference. Unit 8, as noted above, calculated on the memorization of M samples of the modules of the differences of the first order. Since it is a priori unknown number N of summed values of the module of differentials of the first order (this number is determined in block 5 for each of the next cardiac cycle), for reliable operation of the device must satisfy the condition M≥Nmax.

Because it is easy to remember the digital signals at the input of the block 8 can be enabled analog-to-digital Converter 35, made, for example, in the previously mentioned chip PV (Fig.7). Remembering M values of modules of differences of the first order made by using a shift register 36.

Work unit 8 memory modules of differences of the first order is the following. ADC 35 on each of the next sampling is included in the mode conversion signal "start", formed from discrete samples EX driver 34, and converts the value of each of the modules of the differences of the first order coming from block 7, in binary code. Bit outputs of the ADC 35 is connected to the corresponding inputs of the data (D) register 36. Writing data to the register when the signal "Ready" on the output of the ADC 35 "End of conversion". First in the register 36 in the cell with the number 1 written in binary code reference module once the barb of the first order, located after the first start point of the cardiac cycle. On each occasion of sampling this code moves the case from cell to cell. After filling in all the M cells of the register 36 in the cell with the number M will be written in binary code count modulus of the difference of the first order, located closer to the beginning of the cardiac cycle than the samples codes which are recorded in the cells with the numbers M-1, M-2,..., 1. For the summation in block 9 will be used by codes N samples stored in the cells of register numbers m, M-1, M-2,..., M-N. At each regular sampling in the cell case 1 will be written to the next reference of the modulus of the difference of the first order, the contents of each cell will move to a neighboring cell, and the case will be excluded stored in the cell number M code nearest to the beginning of the cardiac cycle count modulus of the difference of the first order.

The operation of forming the sum of N samples at each sampling is implemented in the summation block 9. The work of the summation block 9 is as follows. At each step, the sample is composed of N modules of differences of the first order coming from the block 8. Alternate feed them to the input a of the adder 38 (Fig) is provided with a multiplexer 37, the number of inputs is equal to M, i.e. the number of memory cells of the block 8 of storing samples of the modules of the first differences is orado. The address inputs (inputs And multiplexer 37 of block 5 during each sampling period Δt turn receives the address N of the memory cells of the block 8, which stores the values of the module of differentials of the first order that arrives at the data inputs (inputs D) a multiplexer 37. The output of the multiplexer 37 and then to the adder 38 are only N modules of differences of the first order. The entry in RG1 39 each cumulative value of the sum is carried out pulses "Record 1", following with the same period as the clock pulse counter 29 in block 5. Obtained by adding at each step the discretization of the next N modules of differences of the first order value amounts recorded in the register RG2 40. The repetition period of pulses "Record 2" is equal to the sampling period Δt. Pulses "Record 1" and "2" may be formed by a pulse generator 41. The output of the register RG2 40 is the output of the summation block.

As for determining the threshold level is the maximum value in the block 10 are comparison operations at each step of sampling the received current value of the sum of absolute differences of the first order with the previous and remembering more of them and forming a threshold level. The current sum value S is fed to the inputs a of the comparison circuit 42 two DVO is cnyh numbers and multiplexer MX 44 (Fig.9), the inputs To which are supplied with outputs of the first register RG1 45 presents a binary number, the value stored in the previous step discretization. If the current value of an amount more than the previous value stored in the register RG1 45, the output "A>" of the comparison circuit 42 there is high potential that is supplied to the enable input VA multiplexer MX 44. The output MX 44 and further to the input of the register RG1 45 the signal passes from the input multiplexer, i.e. the current value of the sum, which is recorded in the register 45 signal "Recording1", the next period Δt. When this is stored in the register 45, the value of the sum is replaced by the largest value. If the current value of the sum is less than or equal to the previous, combined OR scheme OR 43 signals a high level output "<" and "a=b" is fed to the input resolution VB multiplexer 44. The output MX 44 and further to the input of the register RG1 45 the signal passes from the input To the multiplexer, i.e. the sum value stored in the register 45. Thus, in the register RG1 45 remains the maximum value of the sum of N modules of differences of the first order Smax.

The threshold level is generated from Smaxmay be represented both in digital and in analog form.

In the first case, the signal Smaxrewritten from RG1 45 in RG2 47 signal "Record 2" as well as, as the signal "Write 1" period Δt, and from the output signal RG2 47 excluded several least significant bits. When, for example, 8-bit representation of Smaxexception 5 to the lower 3 bits allows you to generate the threshold level (0.87-0.97) Smax. The signals "1" and "2" can be generated by the pulse generator 46.

In the second case, the binary number Smaxconverted by means of the DAC 48 (shown in Fig.9 by the dotted line) to an analog signal, from which using a resistive divider 49 is formed threshold level.

The key device 12 is intended for transmission to the output device only discrete samples of electrocardiograma belonging to the ST-segment. Because the timing of cardiomegaly generated by the unit sample 3, is a continuous function (voltage) of a discrete argument (time), the key device 12 may be implemented as an analog switch, for example on a chip CN [8]. A key element 50 (figure 10) chip CN closes (connects the input circuit connected to the output 3 of the circuit with the output circuit connected to the output 2 chip figure 10) when a low level signal at the control input 1 (figure 10). Since the output of the Comparer 11 is formed a high-level signal, as shown at 11,G., prior to input 1 on the bottom of the inverter (figure 10 inverter 51). Thus, when the current values of the sum of N samples of the modules of the differences of the first order exceeds a threshold level (11)at the output of the comparison signal is formed of the control key device (11, g), under which the latter passes to the output device as a whole only counts electrocardiograma belonging to the ST-segment.

Technical and economic effect of the proposed method and device for its implementation is to improve the reliability allocation in real-time ST-segment electrocardiograma regardless of possible deviations from the norm of the parameters of the QRS-complex (shape, amplitude, duration) and heart rate variability. A reliable determination of the ST-segment contributes to the improvement of the conditions for its further processing (determine the offset relative to the contour of the slope, convexity or concavity, and so on), which in turn provides better diagnosis of possible diseases of the cardiovascular system.

Literature

1. RF patent 2026637, class. And 61 In 5/04.

2. The heart monitor. Equipment for continuous monitoring of ECG / Alabakovski, Antilynching, Laanila etc.: edited Alabakovski and Aphemia. M.: Radio and communication. 1993. P.194-204.

3. Bazett H.S. An analysis of time relations of electrocardiograms. Heart 1920; 7:353-376.

4. Mileva KN. Development and study the methods of automatic analysis of the ST segment of the electrocardiogram in real time / abstract. LETI, L., 1989, p.12, 13.

5. RF patent 2195164, class. And 61 In 5/00.

6. Titze U., Schenk, K. Semiconductor circuitry: a reference guide. TRANS. with it. M.: Mir, 1982. 164-167, RIS and 11.47.

7. Ugryumov, H.E. Digital circuitry. SPb.: BHV - Saint Petersburg, 2000. s.89. Is.

8. Chips for consumer devices: a Handbook / Evenascence, VimpelCom, Ipodo, Avereski. M.: Radio and communication, 1989, s, 259.

1. The allocation method ST-segment electrocardiograma in real time, namely, that electrocardiogram (EX) filter, adjust the drift contours, eliminate from the analysis of atypical forms of abbreviations, discretizing time, distinguish the beginning and measure the duration T of each cardiac cycle, characterized in that on each occasion of sampling from a pair of consecutive counts electrocardiograma form a timing difference of the first order, then form the samples of the modules of the differences of the first order and remember N samples of the modules of the differences of the first order, following the reference of the FORMER, corresponding to the beginning of the cardiac cycle, and the number N is determined by the ratio

where T is the duration of the cardiac cycle, Δt is the sampling period, summarize the memorized values of the module of differentials of the first order, then each next step, the disk is misali time exclude from the stored samples of the modules of the differences of the first order first closest to the beginning of the cardiac cycle count and add another newly formed, for a new set stored samples form the sum of the moduli of the differences of the first order, with each sampling compares the current value of the sum of absolute differences of the first order with the previous and remember more of them, and in case of equality of the last maximum of the stored sum value form the threshold level, comparing the current values of the sum of absolute differences of the first order with a threshold level and the point in time at which the sum value becomes equal to or greater than the threshold level is taken as the beginning of the ST segment, and the point in time at which the value before exceeding the threshold level becomes is equal to or less than the threshold, take the end of the ST segment, the length of time between the beginning and the end of the ST-segment is taken for the duration of ST-segment EX.

2. Device for separation of ST-segment electrocardiograma in real-time that contains one United block forming electrocardiograma, block primary processing electrocardiograma made to perform amplification, filtering, correction of drift contours and exclusions from the analysis of atypical forms of abbreviations, and unit sampling, the first output of which is connected to the input of block selection start point of the cardiac cycle and erenia its length, characterized in that the device entered the block of formation of the difference of the first order, the processing unit modules of differences of the first order block memory timing modules of differences of the first order, the unit determining the number of summed samples module of differentials of the first order, the summation block, the block forming the threshold level, the unit of comparison and key device, and the first output unit connected to the sampling input of the block forming the difference of the first order and to the first input key device, the second output unit sampling connected to the first input unit determining the number of summable discrete samples of the modules of the differences of the first order, a second input connected to the output of the block selection point the beginning of the cardiac cycle and measuring its duration, and the output is connected to the first input of the summation block, the output block the formation of the difference of the first order is connected with the input of the processing unit modules of differences of the first order, the output of which is connected to the input unit storing samples of the modules of the differences of the first order, the output of which is connected with the second input of the summation block, the output of which is connected to the input of the shaping unit threshold level and the first input of the comparison, a second input connected to the output of the shaping unit threshold level is, and the output is connected with the second input key device whose output is the output device.



 

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FIELD: medicine; cardiology.

SUBSTANCE: device for processing intervals of electrocardiogram has plate with Q-T (J-T) and R-R scales applied onto the plate. Plate is additionally provided with legs, rod and scale pointer at the end, arrows, and catches disposed at ends of Q-T (J-T) scale, Q-Tc (J-Tc) correlated values curves and Q-Tc (J-Tc) scale related to them. Rod is divided by axis to parts to relate as 1:5 in such a way that shorter part of rod has to be movable leg and longer part has to be the pointer of Q-T (J-T) scale. Pointer takes "0" position of Q-T (J-) scale to rest against left catch when legs close up. Motionless arrow is disposed onto longer part of rod under pointer of Q-T and/or J-T scale at level of "0" position of R-R scale. Slider with lock is mounted onto pointer to move along pointer. Slider is provided with two arrows. Formulas for building curves of Q-Tc (J-Tc) corrected values are given.

EFFECT: higher speed and comfort at processing of electrocardiograms.

3 cl, 8 dwg, 1 tbl

FIELD: medicine, cardiology.

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EFFECT: comfort at usage; higher efficiency at non-invasive application.

2 ex, 2 tbl

FIELD: medicine; cardiology.

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FIELD: medicine.

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2 dwg, 1 ex, 2 tbl

FIELD: medicine.

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FIELD: medicine.

SUBSTANCE: method involves recording rhythmocardiogram. Then, spectral analysis of RR intervalogram components in frequency bandwidth from 0.04 to 0.4 Hz is carried out and information value Z is determined from formula Z=Ahf/Alf, where Ahf is the maximum of high frequency component in bandwidth from 0.14 to 0.4 Hz, Alf is the minimum of high frequency component in bandwidth from 0.04 to 0.14 Hz. Z value being greater than 45 and lower than 14, persons consuming narcotic drugs are detected. Z value being lower than 14, persons consuming sedative drugs like opium, morphine, heroine are detected. Z value being greater than 45, persons consuming psychostimulating drugs like cocaine, amphetamine, efedrone, sydnocarb are detected.

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4 cl, 6 dwg

FIELD: medicine, diagnostics.

SUBSTANCE: the method deals with monitoring the difference in signals obtained from N pickup units, where N ≥ 2, ECG, pulse, temperature and analysis of the range and variability of their rhythms, nonlinear chaotic fluctuations during the period of registration. During analysis one should detect the values for fractal dimensions of Hirst's index and informational Fischer's index standardized, correspondingly, by the average value during either nocturnal or diurnal period. One should conclude upon improved body state by the normalization of signals' difference of peridiurnal rhythm, increased fractal dimensions, Hirst's index, decreased standardized informational Fischer's index, and one should conclude upon worse physiological or pathophysiological processes according to the opposite alterations. The method enables to widen functional possibilities during diagnostics.

EFFECT: higher accuracy of diagnostics.

3 dwg, 6 ex

FIELD: medicine; cardiology.

SUBSTANCE: electrocardiogram of patients with arterial hypertension is subject to twenty-four-hours monitoring. Spectral analysis of variability of heart beating is conducted and low-frequency, very low frequency and high frequency wave components of heart beating are selected. Strength of wave components of heart beating is determined as general, day and night ones. Generalized factor W is calculated by original relation. Value of W is used for diagnosing absence or presence of hormone-active hyper-plastic process of adrenal glands.

EFFECT: screening testing at out-patient conditions.

2 ex, 2 tbl

FIELD: medicine; cardiology.

SUBSTANCE: electrocardiogram of patients suffering from arterial hypertension is subject to twenty-four-hours monitoring. Spectral analysis of variability of heart beating is carried out. Very low frequency, low frequency and high frequency wave components are selected. General, day and night strength of wave components of heart beating is determined. Any factor is estimated according to the data taken from the spreadsheet. Generalized factor Z is calculated by original mathematical relation. Value of Z is used for judging on level of influence of hormones of adrenal gland onto pace-maker activity of sinus node.

EFFECT: comfort at usage; higher efficiency at non-invasive application.

2 ex, 2 tbl

FIELD: medicine; functional medicine.

SUBSTANCE: method in based upon remote irradiation of human body with set of super wide-band electromagnet pulses with duration of 0,2-1,0 ns, repetition rate of 0,05-30,0 MHZ and average density of flow of energy at irradiated part of human body being equal or less than 0,2 mcW/cm2. Modulation component of pulse repetition rate is selected from received reflected signal which pulse repetition rate is determined by heart activity, which is used for forming heart beat rate signal. The latter is used additionally for estimating index of stress which value of index of stress is included into transmitted communication message of mobile phone.

EFFECT: prolonged monitoring of functional condition of human.

3 cl, 2 dwg

FIELD: medicine, cardiology.

SUBSTANCE: one should register a rhythmocardiogram, detect spectral values for variability of cardiac rhythm, calculate the value of autonomic index, calculate the value of autonomic tonicity by the following formula: AI/lnTp m sq. sec., where AI - autonomic index, lnTp - total power for the spectrum of variability of cardiac rhythm. At values above 3.1 one should diagnose severe flow of autonomic dystonia syndrome, at values being 3.1-2.2 - moderate flow of the mentioned disease, at values ranged 2.1-1.5 - light flow. The method enables to predict the development of hemodynamic disorders.

EFFECT: higher efficiency and accuracy of diagnostics.

3 ex

FIELD: medicine; cardiology.

SUBSTANCE: device for processing intervals of electrocardiogram has plate with Q-T (J-T) and R-R scales applied onto the plate. Plate is additionally provided with legs, rod and scale pointer at the end, arrows, and catches disposed at ends of Q-T (J-T) scale, Q-Tc (J-Tc) correlated values curves and Q-Tc (J-Tc) scale related to them. Rod is divided by axis to parts to relate as 1:5 in such a way that shorter part of rod has to be movable leg and longer part has to be the pointer of Q-T (J-T) scale. Pointer takes "0" position of Q-T (J-) scale to rest against left catch when legs close up. Motionless arrow is disposed onto longer part of rod under pointer of Q-T and/or J-T scale at level of "0" position of R-R scale. Slider with lock is mounted onto pointer to move along pointer. Slider is provided with two arrows. Formulas for building curves of Q-Tc (J-Tc) corrected values are given.

EFFECT: higher speed and comfort at processing of electrocardiograms.

3 cl, 8 dwg, 1 tbl

FIELD: medicine, electrocardiography.

SUBSTANCE: the present innovation deals with measuring parameters of electrocardiosignal (ECS) ST-segment and their analysis to detect deviations against the norm. At every step of quantization one should form the readings of first-order differences and modules of first-order differences. One should memorize N of readings for the modules of first-order differences coming after ECS readings that correspond to the onset of cardiocycle. Then it is necessary to sum up memorized values of modules and at every step of quantization one should compare the obtained current sum value with previous one. It is necessary to memorize the greater of them and according to maximal value one should form threshold level to compare current value of modules sum. Time moments when sum value is at first greater and then lower against threshold level one should consider to be, correspondingly the onset and the end of ST-segment. Time segment between the onset and the end of ST-segment should be considered as duration of ECS ST-signal. Device to isolate ECS ST-signal on-line contains a block for forming ECS, a block for primary ECS processing, a quantization block, a block for isolating the point of cardiocycle onset and measurement of its duration, a block to form first-order differences, a block to form modules of first-order differences, a block to memorize readings for the modules of first-order differences, a block to detect the number of summarized readings for the modules of first-order differences, a summarizing block, a block to form a threshold level, a block for comparison and a key device. The innovation enables to isolate ST-segment more reliably for wider class of electrocardiograms at different modifications of QRS-complex form.

EFFECT: higher efficiency.

2 cl, 12 dwg

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