an embodiment of system 10 of the present invention for the analysis and interpretation of ecg signal data obtained from patient 12 comprises of a multi - tier arrangement of an acquisition unit 14 , algorithm server 16 , and database 18 , as shown diagrammatically in fig1 . as shown in fig2 , acquisition unit 14 is coupled to electrodes 20 applied to the chest and extremities of patient 12 . acquisition unit 14 acquires real time ecg signal data via patient connection cable 22 . selected pairs of electrodes , or leads , are used to acquire standard , multiple lead electrocardiographic signal data . acquisition unit 14 may be a device such as a cardiograph , a bedside patient monitor , a holter patient monitor , or other suitable monitor . acquisition unit 14 can also be a portable / handheld device embedded into a cellular phone , electronic messaging unit , personal data organizer , pager , and the like . acquisition unit 14 includes acquisition circuitry 24 for carrying out initial processing of the ecg signal data , such as lead connection quality determination , filtering , pre - amplification , and the like . acquisition circuitry 24 also includes analog - digital conversion circuitry 26 for converting the analog ecg data signals in cable 22 to digitized signals . acquisition circuitry 24 is connected to signal processor 28 having a central processing unit for controlling the operation of acquisition unit 14 and performing the processing or other use of the signal data carried out in acquisition unit 14 . memory 30 for storing ecg signal data is coupled to signal processor 28 . acquisition unit 14 may also include display 32 for providing a graphic and / or textual showing of the electrocardiographic signal data . display 32 typically comprises a cathode ray tube , liquid crystal display , or other suitable apparatus for providing a visually perceptible indication of the data . alternatively , or additionally , a printer provides a paper copy 34 of the ecg data in strip or sheet form . acquisition unit 14 also includes transmitter / receiver 36 that transmits information from , and receives information for , acquisition unit 14 . acquisition unit 14 is connected to algorithm server 16 . algorithm server 16 may comprise a computer server , for example , that manufactured sold by the general electric healthcare unit of the general electric co . under the designation “ muse .” server 16 contains computer algorithms , programs , or other instructions for carrying out desired analyses and interpretation of ecg signal data . algorithm server 16 preferably contains a plurality of ecg algorithms so as to allow use of different algorithms to obtain different results or to combine results , thereby to obtain a more robust cardiac analysis of the patient . algorithm server 16 is connected to the storage device for database 18 . database 18 may be contained in a central , or mainframe , computer for a health services provider , such as a hospital or clinic . database 18 may comprise a component of a hospital information system ( his ). or , database 18 may comprise a dedicated database for system 10 . previously obtained ecg signal data , as well as other patient information , is stored in database 18 . the connections between the components of system 10 may be wired or wireless . or the connection may be effected through a computer network , such as a secure local area network ( lan ) or wireless lan , a secure wide area network ( wan ) or wireless wan or a secure internet connection . it is also possible for algorithm server 16 and the storage device for database 18 to form components of the same computer server unit . fig3 a - 3e diagrammatically show one manner of operation of system 10 . the operation is shown as a real - time ischemic monitoring of multi - lead ecg signal data . such an operation may typically be carried out in a chest pain clinic to assist in determining the presence of a condition , such as acute myocardial infarction or acute cardiac ischemia , in patients suffering severe chest pain . the operation is initiated by a request to the system , either at one of the components or through a link to / from a remote location such as a cardiology laboratory . as shown in fig3 a , in carrying out such an analysis and determination with system 10 of the present invention , acquisition unit 14 acquires ecg signal data from patient 12 via cable 22 . the signal data will typically be 12 / 15 lead ecg signal data . after the initial processing of the acquired real time data in acquisition circuitry 24 and / or signal processor 28 of acquisition unit 14 , the ecg signal data is uploaded to algorithm server 16 , as shown in fig3 b . as shown in fig3 b , it will be appreciated that in a facility such as a chest pain clinic , or hospital unit in which cardiac monitoring is carried out for numerous patients , a plurality of acquisition units 14 a , 14 b , 14 c may be in communication with algorithm server 16 . algorithm server 16 then runs the appropriate computer algorithm to process the ecg signal data received from data acquisition unit ( s ) 14 . see fig3 c . in an example , the algorithm may be a tracing algorithm that continuously traces the morphology of the acquired ecg signal data . following completion of the running of the algorithm , the results may be sent back to acquisition unit ( s ) 14 , as shown in fig3 d , and displayed in display 32 or 34 of the acquisition unit ( s ) or at some other appropriate location in the clinic or hospital . see fig3 e . a typical example of a display produced by an ecg morphology tracing algorithm in algorithm server 16 is shown in fig4 that shows a display of continuous st - t wave monitoring . fig5 a - g show a further use for multi - tier system 10 . specifically , fig5 shows a use of system 10 in carrying out real - time serial comparison of electrocardiographic data . such a comparison is also often employed in a chest pain clinic for monitoring patients for a condition such as acute myocardial infarction or acute cardiac ischemia . fig5 a - 5g show use of multi - tier system 10 in which two - way data flows occur between algorithm server 16 and an acquisition unit or units 14 and data flow also occurs between algorithm server 16 and one or more databases 18 . after algorithm server 16 obtains real - time data from acquisition unit ( s ) 14 and previously stored data from database 18 , algorithm server 16 can run different types of algorithms for providing a desired analysis of electrocardiographic data , and either send the results back to acquisition unit ( s ) 14 or / and to database 18 . the analysis results and original data from acquisition unit ( s ) 14 can also be sent to attending clinicians if immediate care is needed . as shown in fig5 a , in such an application , data acquisition unit 14 acquires real time ecg signal data from patient 12 via ecg cable 22 . in fig5 b , the ecg signal data from acquisition unit or units 14 is uploaded to algorithm server 16 . for purposes of carrying out the comparison of ecg data , algorithm server 16 requests electrocardiographic data previously obtained from patient 12 from the storage device for database 18 . the requested ecg data will typically be that taken from an immediately previous electrocardiographic examination of patient 12 but any stored ecg signal data desired by a clinician may be obtained from database 18 . the request of data from database 18 by algorithm server 16 is shown in fig5 c and the sending of the previously obtained ecg signal data by database 18 to algorithm server 16 is shown in fig5 d . fig5 c notes that the previously obtained signal data may be found in , and obtained from , a number of database locations 18 , 18 a , 18 b , etc . thereafter , algorithm server 16 runs a serial comparison algorithm , as shown in fig5 e to compare the morphology and other aspects of the most recent ecg signal data obtained from the patient with the previous ecg signal data obtained from the patient . the comparison results may then sent to a suitable device for review by a cardiologist or other clinician . fig5 g shows the use of acquisition unit 14 to display and / or print out the results for this purpose but any suitable display , such as a cardiac laboratory workstation may be used to review the results . the processes shown in fig5 a - 5g proceed in real - time , i . e . as the ecg signal data from patient 12 is received , thus resulting in an acceleration of the process of analyzing and interpreting the ecg signal data and diagnosing the cardiac condition of patient 12 . the process may be repeated as needed or at fixed intervals so that any changes in the cardiac condition of the patient with time will become apparent . fig6 shows a typical serial ecg comparison report generated by algorithm server 16 operating in the manner of fig5 e and that can be displayed on acquisition unit 14 . the algorithm or program contained in algorithm server 16 may be one that allows a clinician , following review of the results produced by ecg algorithm , to provide data or edited interpretations to one or both of acquisition unit 14 or server 16 . see fig5 g at 90 . for example , this allows the operation of apparatus 10 to pull forward a previous diagnosis made by the algorithm in server 16 , or portions of previous diagnosis , if there has been no significant change in the electrocardiographic data from patient 10 , as determined by the data comparison . such a program also permits use of a previous detection of the p - wave portion of the electrocardiographic data in order to improve current rhythm detection . the provision of data or edited interpretations may be provided by an appropriate data entry device , such as keyboard 92 shown in fig5 g . fig7 a - 7e shows an operation of system 10 in a manner in which acquisition unit 14 runs one ecg algorithm and algorithm server 16 runs a different ecg analysis or interpretation algorithm . as shown in fig7 a , acquisition unit 14 acquires an electrocardiographic data from patient 12 via an ecg cable 22 . in fig7 b , acquisition unit 14 employs signal processor 28 to run an algorithm , such as real - time heart beat or arrhythmia detection algorithm stored in the signal processor . also as shown in fig7 b , acquisition unit 14 uploads ecg signal data to algorithm server 16 . as shown in fig7 c , algorithm server 16 runs a different ecg analysis algorithm than that being run in acquisition unit 14 . for example , algorithm server 16 may run a real - time shape analysis algorithm . the data analysis results obtained from the running of the two computer programs can be provided to the clinician for a more accurate diagnosis of the cardiac condition of patient 12 as shown in fig7 d . the shape analysis information obtained from the analysis carried out by the algorithm in server 16 can improve the real - time beat arrhythmia analysis performed by the algorithm running in acquisition unit 14 . in addition to embodiments of system 10 in which algorithms are run in algorithm server 18 and additionally in acquisition / monitor unit 14 , system 10 of the present invention may use other data than the real - time signal data obtained from acquisition unit 14 . for example , additional data may be obtained from database 18 in the manner shown in fig5 c and 5d . such additional data may , for example , comprise that derived from a population of patients . in addition to utilizing data stored in database 18 , apparatus 10 may also use information entered by a clinician utilizing apparatus 10 . as shown by block 100 of fig7 e , the clinician reads the displayed graphic or text ecg results relating to the rhythm and shape of the electrocardiographic data . the clinician then inputs interpreted data into acquisition unit 14 by device 102 for use in the algorithm running in acquisition unit 14 and / or the algorithm running an algorithm server 16 . such an over - reading improves the overall accuracy of the determinations made by apparatus 10 , as well as confirming the accuracy of computerized ecg interpretations made by the algorithms in algorithm server 16 and acquisition unit 14 . other examples of the use of edited interpretation for patient monitoring include real - time arrhythmia analysis based on edited interpretation . in this application , an overall edited arrhythmia is cataloged for improving arrhythmia recognition carried out in acquisition unit 14 . examples of edited arrhythmias that could improve computerized recognition of arrhythmia conditions include learning the r - r interval patterns from a segment of historical ecg signal data and real - time sampled ecg signal data so that atrial fibrillation can be properly identified . the r - r interval is the time interval occurring between the prominent r peaks of the qrs portion of successive heart beat waveforms in the ecg data . another example of edited arrhythmias include verification of pace rhythms and the corresponding rate so that they are properly identified during future episodes of pacing . still further , editing may be used for verification of rate dependent conduction abnormalities so that this arrhythmia may be properly labeled by acquisition unit 14 . another example is a real time contour analysis based on edited interpretation . in this application , the overall edited contour of the waveforms in the ecg signal data is cataloged for improving the contour recognition carried out in data acquisition unit 14 . for example , various intervals occurring in the ecg waveforms , such as the q - t interval , the p - r r interval , and the duration of the qrs complex may be measured and confirmed so that future beats are properly recognized and measured . similarly , the identification of repolarization abnormalities that are not the result of an acute process such as those typical of left ventricular hypertrophy with strain can be used , particularly as reference measurements for improving contour recognition . or , identification of significant s - t interval deviation including the point of measure , such as j + 60 , j + 80 , etc . may be edited so that it can be recognized in future episodes . contour recognition may also be employed to determine the effect of certain drugs on the q - t interval of the waveforms of the ecg signal data . a further non - limiting list of examples of edited information that could be entered in system 10 to improve the computerized analysis performed by the algorithms in data acquisition unit 14 and / or algorithm server 16 includes the following related to ecg morphology : double detection of the qrs feature of the electrocardiographic data fixed by correct labeling of the t - wave portion of the electrocardiographic data ; verification of coupling intervals for premature ventricular contractions ( pvcs ) so that artifacts that occur with different coupling intervals are more likely to be recognized as artifacts ; correct identification of p - wave morphology , or template , for subsequent atrial detections ; correct identification of artificially paced beats so that the algorithms of algorithm server 16 or acquisition unit 14 do not indicate idioventricular rhythms ; correct identification of right bundlebranch block ( rbbb ) or left bundlebranch block ( lbbb ), so that beats can be called aberrantly conducted versus ectopic ; proper identification of q - t interval so that trending can be based on edited measurements ; and proper identification of the p - r interval so that trending of first degree atrioventricular ( av ) block can be done based on an edited measurement . while system 10 of the present invention has been described in connection with fig7 with a single ecg analysis algorithm running in algorithm server 16 , it will be appreciated that , as noted above , multiple algorithms may be used and the results and features combined together to improve the accuracy of the single detection and interpretation . for example , for continuous 12 lead ecg data , it is possible to run 12 lead ecg interpretation , heart - rate - variability , and t - wave - alternans algorithms at the same time on algorithm server 16 . various alternatives and embodiments are contemplated as being within the scope of the following claims particularly pointing out and distinctly claiming the subject matter regarded as the invention .
in a multi - tier patient monitoring data analysis system , an algorithm server is positioned as a middle tier between an acquisition device , such as a cardiograph or patient monitor that can be seen as a lower tier , and a storage device for a database , such as that of a central computer for a hospital or clinic that can be seen as an upper tier . the algorithm server gathers current data from the real time acquisition device and obtains previously stored ecg signal data from the database . the algorithm server contains ecg analysis algorithm and runs one or more algorithms using the current and previously acquired ecg signal data . analysis algorithms may also be run on the acquisition device . the system provides the rapid , extensive , and thorough ecg analysis that is critical to patient welfare .