|Publication number||US3755783 A|
|Publication date||Aug 28, 1973|
|Filing date||Aug 4, 1971|
|Priority date||Aug 4, 1970|
|Also published as||DE2139073A1|
|Publication number||US 3755783 A, US 3755783A, US-A-3755783, US3755783 A, US3755783A|
|Inventors||Astarjian G, Hristov H, Nachev C|
|Original Assignee||Inst Technicheska Kib Pri Ban|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (3), Referenced by (8), Classifications (11)|
|External Links: USPTO, USPTO Assignment, Espacenet|
limited States Patent [1 1 Astarjian et al.
1451 Aug. 28, 1973  ARRANGEMENT FOR ANALYZING 3,616,790 ll/l97l Harris 128/206 A IRREGULARITIES IN REPETITIVE BIOLOGICAL PROCESSES Primary Examiner-Donald J. Yusko  Inventors: Garo Bohos Astarjian; Hristo Radev Attorney-Arthur Klem Hrlstov; Chudomlr Klrilov Nachev, all Of Sofia, Bulgaria 57 ABSTRACT [73 1 Assign: Instimt Po Technichesifa Kibemeflka A biomedical analyzer detects the start and stop of difpri Sofia Bulgana ferent types of cardiac rhythm irregularities in a moni-  Fil d; A 4, 1971 tored patient and displays the results in real time. Each successive impulse representative of a dominant, nor- [211 App! 168316 mally repetitive component of the patients heartbeat is instantly classified with respect to the elapsed time  Foreign Application Pri it D t from the occurrence of a preceding impulse. An on-line Aug 4 1970 Bulgaria 15377 computer adapted to recognize any of M predetermined irregular sequences of impulses responds to the  us CL. 340/168 B 126/2 06 A 346/33 ME successive classified impulses to outpulse a first indica-  Int. Cl h l 5/04 tion at the start of each irregular sequence and to fur- 58 1 me of H 68 ther outpulse one of T second indications at the conclu- 346/33 l28/2O6 sion of each sequence, each second indication being l unique to the separate one of the T sequences. Each 56] References Cited first and second indication is displayed on a suitable recorder in the time slot of a simultaneously occurring UNITED STATES PATENTS unclassified impulse. 3,658,055 4/1972 Abe et al. 128/206 A 3,616,791 11/1971 Harris 128/2.06 A 13 Claims, 9 Drawing Figures 2 7 1 1 1 a f r 1 r3 7 i l I i no -i V8 1 T l MEMORY E] A b B l c l l z u I E] u u f 4 i I F 1 LOGIC p Ei [El E1 LOGIC H r RECORDER M.V. CIRCUITRY 9 cmculm, r- E e1 i in -11 5 V 1 5 o, 0,, I I; wt; E] U a 1 i M. V. B I E i I snow 1 I al|||||||i |llimrlllrlilis H M SHEET 2 [If 7 PATENTEUnusaa I973 FIG 2A FIG. 2B
PATENIEmusza ms 3.755783 sum 3 0f 1 FIG. 3
'PAIENIEmum ms ABNORMAL SEQUE NCE ABNORMAL SEQUENCE ABNORMAL SEQUENCE IIJII ABNORMAL SEQUENCE ABNORMAL SEQUENCE IILII ABNORMAL SEQUENCE IIN SHEET 5 BF 7 X X ISOLATED BLOCKING OF THE HEART TYPE 1 a 7 a a f XN XN+| ISOLATED BLOCKING OF THE HEART H TYPE I: a 8 a a 1" "q -+1 ISOLATED BLOCKING OF THE HEART TYPE :11
d Tr a d f" T X X I S N NH ISOLATED BLOCKING (s |,2,- OF THE HEART H TYPE m a 41 a D 1' 7 T /XN /XN+I ISOLATED BLOCKING OF THE HEART H TYPE I a a 1' Tm 4 -+z GROUP OF DELAYED X IMPULSES H H n+3 r r '7 a t 7 T BRADYCARDIA *-l /XN /XN+2 XN+7 v H H H H XN+3 "m4" ll 0 y s s s s of PATENTEDmsza ms .5 7 55; 78 3 SHEETSBF? FIG. 5 y
PATENTEflmcaa ms SHEET 7 0F BINARY N COUNTER FIG. 7
l I l DIGITAL 44 TO ANALOG CONVERTER /45 DRIVE PEN MOTOR RECORDER DIGITAL T0 COMPUTER ANALOG PRINT-OUT CONVERTER I l l A B C p ARRANGEMENT FOR ANALYZING IRREGULARITIES IN REPETITIVE BIOLOGICAL PROCESSES BACKGROUND OF THE INVENTION In one type of prior art biomedical analyzer, an electrocardiogram representative of a patients cardiac rhythm is recorded on a magnetic tape or the like. After a plurality of such records are accumulated, the taped information is suitably converted and sent over telephone lines to a remote general purpose computer. The latter is programmed to analyze each recorded electrocardiogram to ascertain whether the patients cardiac response is normal or abnormal and, if the latter, into what category the abnormality falls. Such a remote off-line analysis is not particularly suitable to local situations where a patients heart must be continually monitored for sudden changes in any number of ways that must be instantaneously detected and treated.
Certain real-time systems have been developed which can be employed to measure and analyze a patient's cardiac response as it occurs. In one such scheme, a succession of impulses derived from the electrocardiogram is divided into sampled intervals having equal numbers of impulses, and the irregularities of each sample are measured with respect to the average frequency of the cardiac rhythm during such sample. This scheme has the disadvantage of being able to detect only a relatively few types of irregularities.
More recently, a computer-aided arrangement has been proposed which analyzes the electrocardiogram output by determining whether the elapsed time between successive impulses is (a) within predetermined limits, (b) shorter than the lower limit, or (c) longer than the higher limit, with the latter two categories representing irregularities. Both the regular and irregular portions of the separated impulses are stored in memory. Unfortunately, with this scheme the information stored in memory is not recoverable in a format suitable for monitoring the real time distribution of the separated irregularities.
SUMMARY OF THE INVENTION These disadvantages are overcome with the use of a real-time biomedical analyzer in accordance with the invention. In one embodiment suitable for analyzing electrocardiograms, a sequence of impulses representative of a principal component of a patients heart rhythm is coupled to an impulse classifier. The classifier has a first pair of monostable multivibrators triggered by each successive impulse for establishing a first time zone, wherein the next succeeding impulse is classified in (a) a normal category, if it occurs within the first time zone, or (b) a first abnormal category if it occurs before the lower time limit of the first time zone. The classifier is also provided with a second pair of monostable multivibrators triggered at the conclusion at the first time zone for establishing a second time zone wherein an impulse following the one that triggered the first timezone is classified in a second abnormal category if it occurs within the second time zone.
Further pairs of additional monostable multivibrators may be provided for establishing other unique time zones to define other categories of irregularities.
A plurality of combinational AND gates associated with the multivibrators define parallel outputs of the classifier, wherein each impulse applied to the classifier effectively excites either (1) a first output representative of the presence of a normal impulse, or (2) one of a plurality of second outputs individually representative of impulses in the separate abnormal categories.
An on-line computer is adapted to recognize any of T predetermined sequences of the so-classified impulses that define medically recognized categories of cardiac irregularities which may be classified as single, group and systematic irregularities. The computer responds to the outputs of the classifier to outpulse (a) a first indication at the start of any of the T recognized sequences, and (b) one of a plurality of second unique indications upon the termination of an associated one of the T sequences. The first and second indications may be displayed in real time on a suitable recorder, which may illustratively be a pen recorder driven in synchronism with separate unclassified impulses, or a computer printout which numerically displays along with such first and second indications the number of impulses between successive indications.
BRIEF DESCRIPTION OF THE DRAWING The invention will be described in further detail in the following description taken in conjunction with the appended drawing, in which:
FIG. 1 is a block diagram of a real time biomedical analyzer suitable for carrying out the invention;
FIGS. 2a and 2b are timing diagrams of illustrative categories in which impulses representative of a normally repetitive biological process are classified in accordance with the invention;
FIG. 3 is a schematic diagram of an arrangement suitable for classifying impulses in the manner indicated in FIG. 2;
FIGS. 4a and 4b are timing diagrams illustrating different sequences of classified impulses which define plurality of medically recognized cardiac irregularities;
FIG. 5 is a flow diagram of a computer suitable foruse in the arrangement of FIG. 1 and programmed to recognize each of the abnormal sequences of classified impulses indicated in FIG. 4; and
FIGS. 6 and 7 are block diagrams of two forms of recording devices suitable for displaying the outputs of the programmed computer of FIG. 1 in real time.
DETAILED DESCRIPTION Referring now to FIG. 1, the output of an electrocardiogram of a patient whose cardiac characteristic is being monitored is coupled to a conventional filter 1 suitable for extracting the normally repetitive, dominant R-wave component of the patients cardiac response. The output of the filter l is applied, as a sequence of normally periodic impulses X to the input of an impulse classifier 2 whose function is depicted diagrammatically in FIG. 2'. .z
The scheme of FIG. 2 is designed to classify each successive impulse X into one of a plurality of unique categories a, B, 'y, 11', Ill, 6, g and typified in FIG. 2a by appropriate ones of the vertical dotted lines. The category for each impulse X is determined by the elapsed time T between the occurrence of the impulse X and the occurrence of the next preceding impulse X- Each such category falls within a unique time zone following the occurrence of the impulse X- with each time zone illustratively chosen in accordance with the following Table 1:
TABLE 1 Classification of lmpulse X a (normal) While not explicitly shown in FIG. 2a, each impulse X ordinarily classified as y, 8, 1r, ill, or C, is classified in a separate category y. if the previous impulse X was classified as y, 8, 11, \II, t, or u.
As shown in FIG. 2b, where an impulse X is classified as B, Table 2 below indicates the following additional categories designated p, 0, e and -y for the next succeeding impulse X These latter classifications are defined by time zones dependent on the elapsed time T between the occurrence of the impulse X and the last preceding non-B impulse K as follows:
TABLE 2 Classification of impulse X,., where impulse X is class- While not explicitly shown in 2b, where an impulse X FlG.2a B-impulse X meets the elapsed time requirement of one of the previously mentioned categories 7, 11', ill, and g with respect to the last non-B impulse X such impulse X is likewise classified as 7, 11', III, or g, respectively.
FIG. 3 depicts one form of impulse classifier 2 suitable for instrumenting the functions depicted in FIGS. 20 and 2b and in the associated Tables 1 and 2. The impulses X are applied as triggers to the active inputs of a first group 3 of monostable multivibrators 11, '12, and 13. The multivibrators 11 and 12 are provided with pairs of complementary outputs R, 17. and S, 5.
When the active inputs of the multivibrators l1 and 12 are triggered, the outputs R and S exhibit pulses having durations T and T respectively, which as indicated in FIG. 2a define the limits of the time zone for impulses X classified in the normal category The values T and T are in general unique to each patient being monitored, and may be preset by appropriately adjusting potentiometers 24 and 23, respectively.
The purpose of the multivibrator 13 is to compensate for the finite fall time of the multivibrators l1 and 12 and may be dispensed with if such fall time may be neglected in a particular monitoring situation. in this latter case, the impulses X may be directly applied to both the active and reset inputs of the multivibrators 11 and 12.
Each incoming impulse X is also applied to one imput of an AND gate 18. The output of the gate 18 is applied to the active inputs of a second group 4 of monostable multivibrators 14, 15, and 16. The multivibrators 14 and 15 are provided with pairs of complementary outputs U, U and W W When the active inputs of the multivibrators l4 and 15 are triggered, the outputs U and W exhibit pulses having durations T and T respectively, as also indicated in FIG. 2.
The output U of the multivibrator 14 is coupled through an OR-gate 17 to a second input of the AND- gate 18.
As with the multivibrator 13, the purpose of the multivibrator 16 is to compensate for the finite fall time of the multivibrators 14 and 15, and may be dispensed with if such fall time may be neglected.
The output W of the multivibrator 15 is coupled to the active input of a multivibrator 19 in a third group 5 consisting of multivibrators 19, 20, and 21. The multivibrator 19 is provided with complementary outputs W W When the active input of the multivibrator 19 is triggered, the output W, exhibits a pulse of duration K,T where K, i 1, which may be preset by the potentiometer 23 in conjunction with suitable internal bias circuitry (not shown) in the multivibrator 19.
The output W, is coupled to the active input of the multivibrator 20. The latter has complementary outputs W W When the active input of the multivibrator 20 is triggered, the output W also exhibits a pulse of duration K T which may be adjusted as indicated above.
The outputs W, and W are coupled through an OR- gate 22 to the active input of the multivibrator 21, which has complementary outputs F, F. When the active input of the multivibrator 21 is triggered, the output F exhibits a pulse of duration K T where K 2 l, which may be preset by the potentiometer 24 in conjunction with suitable bias circuitry (not shown) in the multivibrator 21. i l i The reset inputs of the multivibrators 19, 20, and 21 are coupled to the output of the AND-gate 18.
A logic circuit 6 consisting of a plurality of AND- gates 3143 have outputs that individually define the outputs of the classifier 2. Such outputs in turn represent the categories a, 'y, 0-, 11, 111, C, p, 0, e, 'y, B, and u. The gates 31-43 are individually excited in the manner indicated below when an incoming impulse X is to be classified as specified in FIG. 2.
The output of the gate 42 representing the category B is coupled to a first input of a bistable multivibrator 25, which has complementary outputs Z, Z. The output Z is coupled to one input of an AND-gate 27, whose output is coupled through an OR-gate 30 to a second input of the multivibrator 25. The output 2 is coupled to one input of an AND-gate 28, whose output Q is coupled to a first input of a bistable multivibrator 26 having complementary outputs B, 13. The output B is coupled to an input of the above-mentioned OR-gate 17.
The output S of the multivibrator 12 is coupled to one input of an AND-gate 29, whose output is applied to a second input of the multivibrator 26. The output 5 of the multivibrator 12 is coupled to another input of the AND-gate 28. The impulses X are coupled to additional inputs of the AND-gates 27, 28, and 29.
In addition, in order to establish the specified time zones for each of the categories indicated in Tables 1 and 2, the outputs of the multivibrators 11, 12, 14, 15, 19, 20, 21, 25, and 26 are also selectively coupled to the inputs of the category-establishing AND-gates 31-43 in accordance with the logic equations set forth in Table 3 below:
TABLE 3 Output Category ever a letter in parentheses appears after a classification category, such letter indicates the output line of the computer 7 that is excited at the time that an impulse in such category appears. When no letter appears in parentheses after a category, no output of the computer is excited by the simultaneously occurring classified impulse. (The symbol in the flow diagram, such as in a B, means a or B.)
The manner in which the flow diagram of FIG. 5 executes the desired recognition of the abnormal sequences A through N is summarized in Table 4 below:
TABLE 4 Recognized sequence Computer output line excited during successive impulses in recognized XN start sequence Xma X NH Xms Xw-e XNH The arrangement of FIG. 1 further includes an impulse sequence analyzer 7 coupled to the classified outputs of the impulses analyzer 2. The sequence analyzer 7 is illustratively embodied as an on-line computer suitably adapted to recognize any of the abnormal sequences A through N" of classified impulses depicted in FIGS. 4a and 4b. Such sequences are medically significant as defining different types of cardiac abnormalities indicated on the right side of each depicted sequence. (For comparison, a normal sequence of impulses classified as a is also shown in FIG. 4a).
The computer 7 (FIG. 1) responds to the sequences of classified impulses applied thereto from the classifier 2 by (a) exciting an output line P thereof at the commencement of any of the recognized abnormal sequences A through N," and (b) exciting one of a plurality of output lines A through N thereof upon the termination of corresponding ones of the sequences A" through N. v
The computer 7 includes a memory 8 and a logic circuit 9. The memory 8 is illustratively provided with 16 memory cells a, a only one of which is active at any given moment. Given the function just indicated, a competent circuit designer can hand-wire a special purpose device to instrument this function. Alternatively, if the computer is in the general-purpose category, such function can be instrumented by programming the machine in the manner dictated in the flow diagram shown in FIG. 5. Such program can be set up by any competent programmer. The direction of each arrow indicates the next memory cell excited in response to an incident classified impulse from the classifier 2. Wher- Referring again to FIG. 1, the outputs A-N and P of the computer 7, as well as the output X of the filter l, are coupled to a recorder 10 for displaying the commencement and termination of each of the recognized sequences A" N" in real time.
FIG. 6 shows one embodiment of the recorder 10, which is suitable for use, e.g., where the outputs A-N and P of the computer 7 constitute the outputs of binary stages of successive orders. Such recorder includes a digital to analog converter 44 coupled to the binary outputs of the computer. The output of the converter 44 is coupled to the pen amplifier of a conventional pen recorder 45, so that the pen is driven with an amplitude proportional to the binary weight of the excited output A-N or P of the computer 7. The successive impulses X are applied to the input of the timebase stepping drive motor 46 of the pen recorder 45. The motor 46 steps the pen one position on the time base for each occurrence of an impulse, whether or not a computer output appears. Hence, when the computer is programmed to operate in the manner shown in Table 4, the pen recorder will record both the identification of and the actual time distribution of the starts and stops of each recognized sequence regardless of its length, thereby overcoming the inflexibility of prior-art arrangements that analyze arbitrarily fixed samples having equal numbers of impulses.
An alternative embodiment of the recorder 10 is shown in FIG. 7. A conventional print-out device 47 is provided with a plurality of first channels (not shown) for recording an indication whenever a corresponding first channel input is excited. The device 47 further has a second channel (not shown) for recording a numerical value proportional to the amplitude of a signal applied to the input of the second channel.
The computer output lines A-N and P are individually coupled to the inputs of the first channels of the device 47. The impulses X are applied to the input of a binary counter 47, whose output is coupled to the input of a digital to analog converter 48. The output of the converter 48 is coupled to the input of the second channel of the device 47.
The computer outputs A-N and P are also coupled to inputs of an AND-gate 50, whose output is coupled to reset inputs of the counter 47 and converter 48.
This type of display provides a direct numerical indication of the number of pulses occurring between the start and stop of each of the recognized abnormal sequences, together with an indication of the type of sequence involved.
In the foregoing, the invention has been described in connection with one arrangement thereof. Many variations and modifications will now be evident to those skilled in the art. Accordingly, it is desired that the scope of the appended claims not be limited to the specific disclosure herein.
What is claimed is:
1. A method of analyzing irregularities in a repetitive biological process, which comprises the steps of:
generating a sequence of characteristic impulses corresponding to the successive occurrences of one principal component of the process;
establishing an identical pattern of successive, predetermined time zones following the generation of each successive characteristic impulse;
classifying each of a plurality of successive cycles of the process into one of an arbitrary predetermined number of unique categories determined solely by the time zone in which the associated characteristic impulse is generated relative to the time of occurrence of a preceding characteristic impulse;
detecting the occurrence, within the resulting succession of the categories, of any of T predetermined sequences of the categories, wherein one of such predetermined sequences corresponds to a normal course of the process and the remaining predetermined sequences correspond uniquely to separate recognized irregularities in the process;
generating a first outpulse indication at the start of a detected one of the predetermined sequences and one of T second output indications at the termination of the detected sequence, each of the T second output indications being associated with a separate one of the T predetermined sequences; and
displaying the first and second output indications in real time.
2. In a biomedical analyzer:
means for generating a sequence of characteristic impulses corresponding to the successive occurrences of one principal component of a repetitive biomedical process to be analyzed;
classifying means coupled to the output of the generating means and comprising, in combination, means responsive to the generation of each characteristic impulse for triggering a fixed pattern of successive pulses of predetermined length representative of successive predetermined time zones, and means responsive to the triggering means for producing, in synchronism with each characteristic impulse, one of a plurality of unique indications determined solely by the time zone in which such characteristic impulse is generated relative to the generation of a preceding characteristic impulse; and
computing means coupled to the output of the classifying means and comprising, in combination, means for detecting the occurrence, within the succession of indications from the classifying means, of any of T predetermined sequences of the indications, wherein one of such predetermined se quences corresponds to a normal course of the process and the remaining predetermined sequences correspond uniquely to separate recognized irregularities in the process; a first output; T parallel second outputs; first means coupled to the output of the detecting means for exciting the first output at the start of any detected one of the predetermined sequences; and second means coupled to the detecting means for exciting a unique one of the T second outputs at the termination of an associated one of the detected predetermined sequences.
3. An analyzer as defined in claim 2, further comprising recording means coupled to the outputs of the computing means and to the output of the generating means for individually displaying each output of the computing means in synchronism with the impulse at the output of the generating means.
4. An analyzer as defined in claim 3, in which the outputs of the computing means are binary stages of successively higher order, and in which the recording means comprises, in combination, a pen recorder having a pen amplifier and a time-base drive, a digital-toanalog converter, means for coupling the outputs of the binary stages to the input of the converter, means for coupling the output of the converter to the input of the pen amplifier, and means for coupling the output of the generating means to the input of the time-base drive.
5. An amplifier as defined in claim 3, in which the recording means comprises, in combination, a printout device having a plurality of first channels for individually indicating the presence of an input to each first channel, a second channel for displaying the numerical value of a quantity applied to the input of the second channel, a digital-to-analog converter, means for coupling the output of the converter to the input of the second channel, means for individually coupling the outputs of the computing means to the inputs of the first channels, a binary counter, means for coupling the output of the generating means to the input of the counter, means for coupling the output of the counter to the input of the converter, and means rendered effective upon the presence of an output from the computing means for resetting the counter.
6. An analyzer as defined in claim 2, in which the classifying means comprises aplurality of multi-input coincidence gates having one input coupled to the output of the generating means, the outputs of the coincidence means constituting the outputs of the classifying means.
7. An analyzer as defined in claim 6, in which the classifying means further comprises, in combination, first and second monostable multivibrators each having complementary outputs, first means for simultaneously triggering the first and second multivibrators upon each successive output of the generating means, the first and second multivibrators being responsive when triggered for individually generating pulses having durations of T and T respectively, where T T and means for selectively coupling the outputs of the first and second multivibrators to inputs of predetermined ones of the coincidence gates.
8. An analyzer as defined in claim 7, in which the classifying means further comprises, in combination, third and fourth monostable multivibrators having complementary outputs, second means for normally simultaneously triggering the third and fourth multivibrators upon each successive output of the generating means, the third and fourth multivibrators being responsive when triggered for individually generating pulses having durations of T and T respectively, means rendered effective during the occurrence of a pulse at the output of the third multivibrator for inhibiting the second triggering means, and means for selectively connecting the outputs of the third and fourth multivibrators to inputs of predetermined ones of the coincidence gates.
9. An analyzer as defined in claim 8, in which the classifying means further comprises, in combination, fifth and sixth monostable multivibrators having inputs coupled to the output of the fourth multivibrator, the fifth and sixth multivibrators being triggerable at the conclusion at each pulse at the output of the fourth multivibrator for individually producing pulses having durations of K T and KgTL, respectively, where K, E l and K; l, and means for selectively connecting the outputs of the fifth and sixth multivibrators to inputs of predetermined ones of the coincidence gates.
10. An analyzer as defined in claim 9, in which the classifying means further comprises, in combination, a bistable multivibrator having complementary outputs; means rendered effective upon an output of a selected one of the coincidence gates for triggering a first input of the bistable multivibrator; means rendered effective upon the occurrence of an impulse from the generating means following the triggering of the first input of the bistable multivibrator for triggering a second input thereof; and means for selectively coupling the outputs of the bistable multivibrator to inputs of predetermined ones of the coincidence gates.
11. An analyzer as defined in claim 10, in which the classifying means further comprises means associated with each of the first, second, third, fourth, fifth and sixth monostable multivibrators for establishing the above-mentioned durations of the pulses at their respective outputs when their respective active inputs are triggered.
12. A method as defined in claim 1, in which the establishing step is accomplished by triggering the start of a first one of the time zones at a predetermined time after the occurrence of each characteristic impulse, and triggering the start of a second one of the time zones at a predetermined time after the termination of the first time zone, whereby a third one of the time zones is defined between the time of occurrence of said characteristic impulse and the start of the first time zone and a fourth one of the time zones is defined between the termination of the first time zone and the start of the second time zone, the occurrence of the next characteristic impulse within the first time zone indicating a normal category and the occurrence of such next characteristic impulse in one of the remaining time zones indicating a corresponding one of a plurality of abnormal categories.
13. A method as defined in claim 1, in which at least five time zones are defined during the establishing step. III
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|U.S. Classification||600/515, 346/33.0ME, 340/573.1, 126/2|
|International Classification||G06F17/00, A61B5/024, A61B5/0245|
|Cooperative Classification||A61B5/7264, A61B5/0245|
|European Classification||A61B5/72K12, A61B5/0245|