US20040106875A1 - Medical testing telemetry system - Google Patents

Abstract

A medical testing system includes telemetry features whereby physiological data collected by a collection device at a medical facility is transmitted to a remote processing center for analysis by a trained analyst to provide a test result. In one embodiment, the collection device is a heart rate monitor capable of collecting data with which heart rate variability can be assessed. The heart rate monitor includes a display on which is displayed a waveform showing the breathing performance of the patient during data collection along with standards against which to compare the waveform in order to determine the extent to which the patient followed a predetermined breathing regimen during data collection. The operator of the monitor can use the performance waveform to assess how well the test was taken (i.e., how well the patient complied with the prescribed breathing regimen) and can accept or reject the physiological data accordingly. Also described is a medical testing telemetry system including two processing centers, with each collection device being capable of communicating with both processing centers. Each collection device randomly chooses one of the processing centers for analysis of the collected physiological data. The two processing centers are interconnected in order to permit physiological data and test results to be replicated and stored at both sites.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS
• Not applicable.[0001]
STATEMENT REGARDING FEDERALLY FUNDED RESEARCH
• Not applicable.[0002]
BACKGROUND OF THE INVENTION
• Heart rate variability has been measured and evaluated to provide an indicator of a patient's autonomic nervous system function. The autonomic nervous system, including the sympathetic and parasympathetic systems, governs involuntary actions of cardiac muscle and certain body tissue. Autonomic neuropathy affects the nerves that serve the heart and internal organs and produces changes in many processes and systems. Autonomic neuropathy is most commonly linked to diabetes; however, several causes are possible, including alcoholism, sleep apnea, and coronary artery disease. Thus, evaluation of the autonomic nervous system function has wide applicability, from diagnosing and treating patients with diabetes to detecting patients at risk for sudden death due to cardiac arrest.[0003]
• Heart rate variability monitors perform signal analysis on physiological signals, such as ECG signals, in order to measure the interval between certain phenomena, such as the interval between peaks (i.e., R-waves) of the QRS complex, or the R-R interval, to provide an indication of heart rate versus time. Methods and apparatus for accurately detecting R-R intervals are described in U.S. Pat. No. 5,984,954, entitled “Methods and Apparatus for R-Wave Detection.”[0004]
• Various tests have been developed to exercise the autonomic nervous system for purposes of measuring heart rate variability. Two illustrative tests are the Valsalva test and the Expiration/Inspiration (E/I) test, which is sometimes referred to as the metronomic test. The Valsalva test requires that the patient forcibly exhale to a predetermined pressure, such as 40 mmHg, for a predetermined duration, such as 15 seconds, during which the heart rate is monitored. Thereafter, the patient rests for a predetermined duration. The result of the Valsalva test is a ratio of the highest heart rate (as indicated by the shortest R-R interval) during the breathing maneuver to the lowest heart rate (as indicated by the longest R-R interval) during a recovery period after the maneuver. In accordance with the E/I test, the patient is instructed to breathe deeply at a frequency of 6 cycles/minute, which has been shown to produce maximal heart rate variability in healthy individuals. The result of the E/I test is a ratio of the average of the heart rate peaks to the average of the heart rate troughs. Several other tests for exercising the autonomic nervous system are used, including the standing test in which the patient's heart rate in both supine and standing positions are compared, and frequency under the power spectrum density curve tests.[0005]
• Heart rate variability tests are generally performed in a physician's office, at a hospital, or other medical facility. The accuracy of the test results is a function of many factors including the extent to which a patient complies with the particular breathing regimen of the test, the signal processing techniques used to evaluate heart rate variability, and the skill of the medical technician or other operator of the heart rate monitor in administering the test.[0006]
SUMMARY OF THE INVENTION
• It is an object of the present invention to improve the accuracy of heart rate variability test results.[0007]
• It is a further object of the invention to facilitate training of medical personnel operating heart rate monitors in order to further improve the accuracy of heart rate variability test results.[0008]
• These and other objects of the invention are achieved by a heart rate variability system including heart rate monitors for collecting physiological data from patients at a medical facility and a processing center located remotely from, and in communication with the heart rate monitors. The processing center receives the physiological data and analyzes the data to provide test results based on the patient's heart rate variability and indicative of the patient's autonomic nervous system function. The processing center may transmit the results to the heart-rate monitor at which the data was collected. In one illustrative embodiment, the analysis performed at the processing center includes use of an automated technique for detecting R-R intervals and also includes intervention by a trained analyst to more accurately identify R-R intervals and anomalies in the resulting heart rate versus time waveform. With this arrangement, the accuracy of the heart rate variability test results is improved due to the use of rigorous automated heart rate variability detection techniques at the processing center and intervention by trained analysts.[0009]
• Also described is a medical testing system including collection devices for collecting physiological data from patients at a medical facility and a remote processing center for analyzing the physiological data, with each of the collection devices including a display for displaying a waveform showing the patient's performance during collection of the data. Also displayed are performance standards against which to compare the performance waveform in order to determine the extent to which the patient followed a predetermined breathing maneuver during data collection. A user interface of the heart rate monitors is responsive to inputs indicating acceptance of the physiological data if the comparison reveals less than a predetermined deviation between the performance waveform and the performance standards or rejection of the physiological data if the comparison reveals greater than a predetermined deviation. In one embodiment, the test results are compared to predetermined acceptance criteria at the processing center and are rejected if the comparison reveals greater than a predetermined deviation between the results and the predetermined acceptance criteria.[0010]
• With this arrangement, the accuracy of the test results provided by the processing center is enhanced, since such test results are based only on raw physiological data collected during “well-performed” testing. Stated differently, errors in test results caused by poor test taking are reduced. Thus, because bad physiological data generally will be rejected by the operator of the heart rate monitors and test results falling outside of predetermined acceptance criteria are rejected at the processing center, the accuracy and reproducibility of the tests is improved.[0011]
• According to a further aspect of the invention, a medical testing system utilizes at least two redundant processing centers. The system includes at least one collection device in communication with first and second processing centers, each operable to receive physiological data from the collection device, analyze the physiological data to provide a test result, and optionally transmit the test result back to the collection device. In one embodiment, the collection device randomly selects one of the processing centers for receipt of physiological data.[0012]
• The use of two processing centers advantageously provides analyst availability even in the event of a failure at one of the processing centers or in the communication link to one of the processing centers. Further, use of two processing centers in the medical testing environment of the present invention provides the additional advantage of permitting system changes to be made and extensive, Federally mandated testing to be performed without impacting processing center access, since testing can be performed at one processing center while the other processing center supports collection devices.[0013]
• The two processing centers are interconnected, preferably by two, redundant communication links. In normal operation, physiological data transmitted to either processing center and test results generated at either processing center are replicated for storage at the other processing center. With this arrangement, since all patient test results are stored at both processing centers, either processing center is capable of providing historical, or trending data to patients and their physicians. Further, in the case of a fault at one of the processing centers relating to its ability to analyze data and generate test results, the unanalyzed physiological data can be analyzed at the other processing center.[0014]
BRIEF DESCRIPTION OF THE DRAWINGS
• The foregoing features of this invention, as well as the invention itself, may be more fully understood from the following description of the drawings in which:[0015]
• FIG. 1 is a block diagram of a medical testing telemetry system according to the invention;[0016]
• FIG. 2 is a block diagram of an illustrative collection device in the form of a heart rate monitor for use in the system of FIG. 1;[0017]
• FIG. 2A shows an exemplary breathing performance waveform of pressure versus time for use in connection with the Valsalva test;[0018]
• FIG. 2B shows an exemplary breathing performance waveform of volume versus time for use in connection with the E/I test;[0019]
• FIG. 3 is shows an illustrative database structure for the heart rate monitor of FIG. 2;[0020]
• FIG. 4 is a block diagram of an alternative medical testing telemetry system incorporating a processing center redundancy feature of the invention;[0021]
• FIG. 5 is a more detailed block diagram of the redundant processing centers of FIG. 4;[0022]
• FIG. 6 is a flow diagram illustrating the transfer of raw physiological data from a collection device to a processing center;[0023]
• FIG. 7 shows an illustrative database structure for the processing centers of FIG. 5; and[0024]
• FIG. 8 is a flow diagram illustrating operation of analyst workstations at the processing centers of FIG. 5.[0025]
DETAILED DESCRIPTION OF THE INVENTION
• Referring to FIG. 1, a block diagram of a medical[0026]testing telemetry system10 includes a plurality ofcollection devices14a, . . .14n, each one coupled to a remotely locatedprocessing center20 by acommunication link24. It is contemplated that thecollection devices14a-14nbe located at a physician's office, hospital, or other medical facility.
• The[0027]collection devices14a-14nare operable to measure physiological signals of a patient which are processed to provide a corresponding test result. The collection devices optionally may perform preliminary, real-time signal processing on the collected data, as will be described further in connection with the illustrative heart rate monitor of FIG. 2. However, it is contemplated that the accuracy and thus, the usefulness of the test results is improved by having a trained analyst located at theprocessing center20 analyze the physiological data to provide final test results. The test results may be transmitted by theprocessing center20 to the collection device at which the physiological data was collected, as is described below. Alternatively, the test results may remain at the processing center, for example for viewing over a web browser.
• Each[0028]collection device14a-14nis coupled to theprocessing center20 by a communication connection, or link24 which includes the public telephone system and may be implemented with various types of hard-wire or wireless media and may further include one or more public or private networks, such as a local area network (LAN) or a wide area network (WAN) which may be part of the Internet.Typical communication links24 are implemented with Plain Old Telephone Service (POTS) lines or a combination of POTS and voice T1 lines. In one illustrative embodiment, thecommunication link24 includes a T1 line comprising 24 digital channels at theprocessing center20 and individual POTS lines at eachcollection device14a-14n. A telephone company switch coupled between thecollection devices14a-14nand the processing center performs the necessary multiplexing and demultiplexing functions. Thecommunication link24 may also include a radio frequency (RF) connection which allows the operator of adevice14a-14nto move the device without requiring a hard-wire connection to a telephone line.
• In one illustrative embodiment, each of the[0029]collection devices14a-14nis a heart rate monitor of the type shown in FIG. 2, which is operable to collect physiological data from patients for use in evaluating the patient's heart rate variability and thus, autonomic nervous system function. It will be appreciated by those of ordinary skill in the art that although much of the following description of thetelemetry system10 of FIG. 1 and thealternative telemetry system130 of FIG. 4 relates to the illustrative heart rate variability application, the apparatus and techniques described herein may be used in connection with other types of medical testing apparatus, such as electrocardiogram machines, x-ray machines, and MRI machines, while still achieving the described advantages.
• Referring to FIG. 2, the illustrative[0030]heart rate monitor14 includes aprocessor26, auser interface28, amemory32, adisplay36,data acquisition elements40, andpatient interface elements44. Theprocessor26 executes programming instructions by which a patient's heart rate variability is analyzed in real-time in response to the measured physiological data, such as an ECG signal and, optionally, also a blood pressure signal. In the illustrative embodiment, theprocessor26 at the collection device performs R-wave detection processing on the patient's ECG signal to generate the heart rate versus time signal for real-time display. The R-wave detection processing performed on the ECG signal to generate the heart rate versus time signal by theprocessor26 may be the same as, or different than the R-wave detection processing performed at theprocessing center20. In the illustrative embodiment, both the heartrate monitor processor26 and theprocessing center20 implement an R-wave detection scheme of the type described in U.S. Pat. No. 5,984,954, entitled “Methods and Apparatus for R-Wave Detection,” which patent is incorporated herein by reference in its entirety. However, the heart rate versus time data generated at theprocessing center20 and used to compute the test results (e.g., the Valsalva and E/I ratios) is the result of a combination of R-wave detection processing techniques and trained analyst intervention.
• The[0031]processor26 may take various forms, such as a conventional microprocessor of a standard personal computer, workstation or other microprocessor-driven device. As one example, theprocessor26 is an INTEL-compatible microprocessor of an IBM-compatible personal computer running the MICROSOFT WINDOWS graphical user interface. In fact, theheart rate monitor14 may be implemented using a standard personal computer chassis with certain components (e.g., the data acquisition components40) provided in the form of circuit modules adapted for insertion into I/O ports of the computer. Amodem38 permits a dial-up connection to be established with theprocessing center20 over aPOTS line24.
• The[0032]memory32 includes a Random Access Memory (RAM) for temporary data storage and a device with read/write access for permanent data storage, such as a hard drive. Adatabase34 is provided for storing patient information, test session information, and test results provided by theprocessing center20. One illustrative format for thedatabase34 is described below in conjunction with FIG. 3. In the illustrative embodiment, raw physiological data and test performance data are stored in files external to thedatabase34.
• The[0033]user interface28 may be provided by a number of conventional devices, such as a keyboard, touch screen, arid/or mouse. In one illustrative embodiment, theuser interface28 includes a touch screen incorporated into thedisplay36 and the display is a s flat panel LCD display. It will be appreciated by those of ordinary skill in the art that many of the components described herein may be implemented with various hardware and software.
• The[0034]data acquisition components40 of theheart rate monitor14 include anECG amplifier46, afirst pressure transducer48 for measuring the pressure at which the patient exhales for use in connection with the Valsalva test and asecond pressure transducer49 for measuring the patient's inspiration flow for use in connection with the Expiration/Inspiration (E/I) test. While the illustrativeheart rate monitor14 is described herein in connection with performing the Valsalva and E/I tests, it will be appreciated by those of ordinary skill in the art that other tests of heart rate variability using the illustrateddata acquisition elements40 may also be performed with theheart rate monitor14. It will also be appreciated that other physiological signals, such as blood pressure, may be collected by theheart rate monitor14 by adding corresponding data acquisition and patient interface components and software.
• The[0035]ECG amplifier46 operates with a conventionalECG patient interface54, such as electrode pads adapted for attachment to a patient's chest, and includes signal processing circuitry for conditioning the measured ECG signal for further processing. One suitable commercially available ECG amplifier is of the type sold by Serena Medical Electronics Co., Inc. of San Jose, Calif. under the product name ECG Isolation Amplifier Module Model ECG-170. The output of theECG amplifier46 is converted into a digital signal by an analog-to-digital (A/D)converter50.
• The[0036]pressure transducer48 is coupled to aconventional patient interface56, such as a mouthpiece into which a patient breathes. Thepressure transducer48 measures the pressure differential across a diaphragm within the mouthpiece to provide a pressure transducer output signal indicative of the pressure at which the patient breathes. The pressure transducer output signal is digitized by the A/D converter50. When themouthpiece56 is used in connection with thepressure transducer49, one end of the mouthpiece is covered. Thepressure transducer49 provides to the A/D converter an output signal indicative of the patient's inspiration flow. The digitized ECG, pressure, and inspiration flow signals are coupled to theprocessor26.
• According to one aspect of the invention, the pressure and inspiration flow signals which provide breathing performance data are used to evaluate how well a patient performs a particular test. The performance data may also be used to provide feedback to the patient in order to enhance patient compliance with a particular breathing maneuver, as described in a U.S. patent application Ser. No. 08/942,710, entitled “Method and Apparatus for Enhancing Patient Compliance during Inspiration Measurements.”[0037]
• More particularly, a breathing performance waveform illustrating parameters of the patient's breathing during the collection of physiological data for each test is displayed on[0038]display36 to the operator of themonitor14 in order to permit an assessment to be made as to how well the particular test was performed (i.e., how closely the patient complied with the breathing maneuver associated with the test). Also displayed are standards against which the operator can readily compare the breathing performance waveform. In one embodiment, performance standards are superimposed on the breathing performance waveform in order to facilitate ready comparison of the performance data to the standards. The operator can then accept or reject the raw physiological data as a function of the extent to which the performance data falls within the standards. If, for example, the operator determines that the patient did not closely comply with the specified breathing regimen during data collection, then the raw physiological data can be rejected and new data collected. Alternatively, if the operator determines that the patient closely conformed to the specified breathing regimen, then the raw physiological data is accepted and transmitted to theprocessing center20 for analysis.
• In one illustrative embodiment, the raw physiological test data is stored in a temporary data file in[0039]memory32 until the operator indicates acceptance or rejection of the test via theuser interface28 based on evaluation of the performance data. If the test is accepted, then the temporary data file is renamed and placed into thecollection device database34, following which the operator can transmit the data to theprocessing center20 for analysis and generation of test results. Alternatively, an indication of rejection of the test data causes the temporary data file to be deleted.
• With this arrangement, the accuracy of the test results provided by the[0040]processing center20 is enhanced, since such test results are based only on raw physiological data collected during well-performed testing. Stated differently, errors in test results caused from poor test taking are reduced. Thus, because bad physiological data is rejected, the reproducibility of the tests is improved.
• Referring also to FIG. 2A, an illustrative[0041]patient performance waveform60 shows pressure versus time during performance of the Valsalva test. Also displayed in the form of a numerical value is astandard deviation62 which represents the extent to which the patient's breath pressure deviates from the nominal desired 40 mmHg value. The performance standards superimposed on thewaveform60 may include a maximumpressure value Pmax64, a minimumpressure value Pmin66, a maximumbreath interval Tmax68, and a minimumbreath interval Tmin70. It will be appreciated by those of ordinary skill in the art that other performance standards may also be displayed.
• The operator is provided with guidelines for accepting or rejecting the test data. For example, the operator may be instructed that if the breath pressure remains between Pmax and Pmin for a duration between Tmax and Tmin and the standard deviation is less than a specified percentage, then the test data can be accepted since such conditions indicate that the patient substantially complied with the prescribed breathing maneuver.[0042]
• Referring to FIG. 2B, in the case of the E/I test, a[0043]patient performance waveform74 shows volume over time, which is provided by integrating the measured inspiration flow signal. Also displayed are standards for use by the operator in assessing the value of the physiological data in the form of a deep breathingmaximum value Vmax78 and a deep breathingminimum value Vmin80. In the illustrative embodiment, the deep breathing maximum value is set equal to the volume of a reference breath taken by the patient and the deep breathing minimum value is set equal to 60% of the reference volume. In this example, the operator may be instructed that substantial compliance with the desired breathing regimen requires that four of every six breathes fall between the deep breathingmaximum value78 and the deep breathingminimum value80. It will be appreciated by those of ordinary skill in the art that other measures of test performance, performance standards, formats of presentation, and operator instructions are possible.
• Preferably, once raw physiological data is accepted and transmitted to the[0044]processing center20 for analysis, an analyst verifies the operator's decision to accept the physiological data. For this purpose, the test performance data (e.g. breath pressure versus time for the Valsalva test) is transmitted to the processing center along with the raw physiological data. In the illustrative embodiment, the analyst is provided with the same test performance information as the heart rate monitor operator (e.g.,waveform60 of FIG. 2A andwaveform74 of FIG. 2B) for purposes of verifying the accept/reject decision.
• According to a further aspect of the invention, an operator of the[0045]heart rate monitor14 can transmit to theprocessing center20 test performance data known to be the result of a poorly administered test for the purpose of having a trained analyst study the test performance data and provide consulting advice as to the likely cause of the problem. For example, where an E/I test performance waveform74 (FIG. 2B) illustrates that the patient is breathing to a volume between 200% and 300% of the reference breath volume, the analyst can infer that the reference breath volume was improperly measured and instruct the operator to re-measure the reference breath volume.
• Referring also to FIG. 3, an illustrative format for the[0046]collection device database34 is shown. In the illustrative embodiment, thedatabase34 is a Microsoft Access 97 database. However, it will be appreciated by those of ordinary skill in the art that various database packages may be used. It will also be appreciated that the database structure shown in FIG. 3, as well as the structure of the database at the processing centers (FIG. 7), is illustrative only and may be readily varied to achieve different database efficiencies and goals.
• The[0047]database34 includes a Patients table100 in which patient demographic information is stored, a Sessions table102 containing a single entry for each test session, where a test session includes one or more tests performed on a patient at a given time, and a Tests table104 containing data types common to each of the tests performed in the respective session. Each patient is identified in the Patient's table100 by a unique identifier (Patient_id) unrelated to the patient's actual identity. Although the entry in the Patient's table100 for a given patient contains fields for his name, it is the Patient_id that is used throughout thesystem10 to identify the patient in order to preserve patient confidentiality. The Sessions table102 contains information describing the test session, including, but not limited to the Patient_id, the date, the start and stop times of the session, the date that the collected physiological data is transmitted to theprocessing center20, whether the data has been analyzed and if so, when analysis occurred. Each entry in the Sessions table102 has one or more corresponding entries in the Tests table104 according to how many tests are performed during the given session.
• Also provided are tables corresponding to each of the types of tests performed by the[0048]heart rate monitor14 which include, in the illustrative embodiment, a Valsalva table110, a Metronomic (E/I) table114 and a Stand table118. Each entry in the Tests table104 has a corresponding entry in one of the Valsalva table110, the Metronomic table114, and the Stand table118 once the test results are returned to the collection device.
• Following analysis of the raw physiological data by the[0049]processing center20 and transmission of the test results to theheart rate monitor14, the test results are entered in the appropriate one(s) of the tables110,114,118. For example, the Valsalva ratio (i.e., ValsalvaRatio) is entered in the Valsalva table110 and the E/I ratio is entered in the Metronomic table114 (i.e., AvgMaxHR_div_AvgMinHR).
• Additional entries in the[0050]database34 following receipt of test results include unique identifiers of the patient, test session, and each analyzed test in the form of an AnalysisSitePatient_id entry in the Patients table100, an AnalysisSiteSession_id entry in the Sessions table102, and an AnalysisSiteTest_id entry in the Tests Table104, respectively. Also entered into thedatabase34 in response to receipt of a results file is an AnalysisStatus entry in the Sessions table102 which indicates the status of the test session data as having been analyzed or not, and possible entries in the Error table120. More particularly, if a particular test is rejected at the processing center, then an identifier of the test (i.e., Test_id) is entered in an Error table120, along with the reason for rejection.
• Optional tables include a BaselineBPs table[0051]124 and a StandBPs table126, both of which are intended for use with heart rate monitors equipped with a blood pressure acquisition device. In certain cases, it is desirable to measure instantaneous blood pressure with the patient in a supine position and then in a standing position. The two blood pressure measures are compared and evaluated along with heart rate variability in order to diagnose various disorders, such as orthostatic hypotension. Each entry in the Sessions table102 may have an optional series of entries in the BaselineBPs table124 that correspond to the baseline blood pressure readings obtained during the Baseline test and an optional series of entries in the StandBPs table126 that correspond to blood pressure readings obtained while the patient is standing.
• In order to support a remote client software update procedure, the[0052]collection device database34 contains a Version table128 in which the version of the structure ofcollection device database34 is stored. The database structure version corresponds to the software version with which it was introduced.
• The “results file” which contains test results uploaded from the[0053]processing center20 to thecollection device14 also identifies the most recent version of the client software available (i.e., the software run on the collection devices which is responsible for physiological data acquisition, data transfer to the processing center, signal analysis to provide real-time heart rate versus time data, etc.). Each time a results file is received by acollection device14, the collection device compares the software version of its executable file with the most recent software version specified in the results file. If the client software versions differ, then the collection device is scheduled to receive a software update. In one illustrative embodiment, thecollection device14 initiates downloading of an update application containing the updated software from theprocessing center20 after a predetermined duration. In addition to the latest version of client software, the update application specifies the database structure version required of thecollection device database34 in order to run the updated software. If the update application specifies a database structure different than the database structure version contained in the Version table128, then the update application also updates the structure of thedatabase34 and enters the updated database structure version in the Versions table128.
• Referring also to FIG. 4, an alternative medical[0054]testing telemetry system130 incorporating a processing center redundancy feature of the invention includes a plurality of collection devices132a-132nand twoprocessing centers140 and142. As will become apparent to those of ordinary skill in the art, a minimum of twoprocessing centers140,142 is necessary in order to achieve the benefits described below. However, more than two interconnected processing centers may be desirable in certain applications. Illustrative collection devices132a-132nare heart rate monitors of the type shown in FIG. 2.
• Each of the collection devices[0055]132a-132nis capable of communication with thefirst processing center140 via acommunication link134aand with thesecond processing center142 viacommunication link134b.Like the communication links24 of FIG. 1,links134a,134binclude the public telephone system and may be implemented with various types of hard-wire or wireless transmission media and may include one or more public or private networks, such as a local area network (LAN) or a wide area network (WAN) which may be part of the Internet.Typical communication links134a,134bare implemented with POTS lines or a combination of POTS and voice T1 lines. Thus, each collection device132a-132nrequires configuration of two point to point protocol (PPP) networking configurations in its modem. In one illustrative embodiment, each link134a,134bincludes a T1 line comprising 24 channels at theprocessing center140,142 which are demultiplexed through the telephone system to provide24 connections via POTS lines for coupling to collection devices. Preferably, each of thelinks134a,134bis implemented by a different carrier in order to mitigate failures due to equipment trouble or clerical errors.
• In a preferred embodiment, each of the collection devices[0056]132a-132nrandomly selects one of the processing centers140,142 for transmission of physiological data for analysis. For example, where the collection device is aheart rate monitor14 shown in FIG. 2, theprocessor26 of the heart rate monitor executes a routine by which a random one of two possible telephone numbers associated with the twoprocessing centers140,142 is dialed by themodem38. In the event that a dial-up connection cannot be established with the selected processing center, the modem dials the other telephone number. With this arrangement, under normal conditions, the load on the processing centers140,142 is shared substantially equally.
• Use of two[0057]processing centers140,142 advantageously provides analyst availability even in the event of a failure at one of the processing centers or in the communication link to one of the processing centers. Further, in the medical testing environment of the present invention, use of twoprocessing centers140,142 provides the additional advantage of permitting system changes to be made and extensive, Federally mandated testing to be performed without impacting processing center access. More particularly, improvements are continuously made to the software with which the analysts process physiological data to provide test results and software governing the operation of the processing centers. The Federal Food and Drug Administration (FDA) requires significant testing of any modifications to approved medical systems. With the two-processing center topology of FIG. 4, such improvements can be made as they are developed without the inconvenience of system down time, since the improvements can be tested at one processing center while the collection devices132a-132nare supported by the other processing center.
• The processing centers[0058]140,142 are interconnected by a pair ofredundant communication links148,150, as shown. It will be appreciated by those of ordinary skill in the art that the particular choice of communication link type can be varied. As with the links between collection devices and processing centers, thelinks148,150 between the two processing centers can be implemented with various hard-wire or wireless transmission media and may include one or more public or private networks. In the illustrative embodiment, one of thelinks148 is a data T1 line and theother link150 is a data ISDN line. Preferably, the twolinks148,150 are of either different types and/or are controlled by different carrier companies, in order to reduce incidences of failed communication between the processing centers.
• In normal operation, both the physiological data received at either[0059]processing center140,142 and test results generated at eitherprocessing center140,142 are replicated and stored at both processing centers. With this data synchronization arrangement, data backup is achieved. Further, since all patient test results are stored at both processing centers, either processing center is capable of providing historical, or trending data to patients and their physicians, as may be desirable any time tests are performed. For example, every time test results are generated by a processing center and uploaded to a collection device, previous test results of that patient may be uploaded as well. Another advantage of the interconnected processing centers storing replicated data occurs in the case of a fault at one of the processing centers140,142 relating to its ability to analyze data and generate test results (e.g., inoperable analyst workstations). In this case, the unanalyzed physiological data can be analyzed at the other processing center.
• Additional optional connections to one or more public and/or[0060]private networks160 can be made to one or both of the processing centers140,142 in order to enhance features of the medicaltesting telemetry system130. As one example, thenetwork160 may be used to permit customer service personnel to assist operators of the collection devices132a-132nhaving difficulty administering tests. In this case, such customer service personnel can be located at a further remote site connected to a processing center through a private network or the Internet. An analyst at one of the processing centers can forward to the customer service representative information regarding poor test performance data and the expected cause (e.g., an inaccurately measured reference breath volume of an E/I test). The customer service representative can then contact the operator and provide instruction to how to improve test performance.
• As an another example of a further network connection to one or both of the processing centers, patients and their physicians can be provided with access to test results stored at the processing centers through[0061]network160. Such anetwork160 would include the Internet and require strict security features to be implemented in order to preserve patient confidentiality, such as encryption and/or use of a patient ID and password combination.
• Referring also to FIG. 5, a diagram of illustrative processing centers[0062]140,142 is shown. The elements of the processing centers are substantially identical, with like reference numbers referring to like elements. Thus, for simplicity, the processing center structure and components will be described in connection withillustrative processing center140. The structure of the processing centers140,142 is also illustrative of the structure of theprocessing center20 of FIG. 1, with the exception that therouter182 andcommunication links148,150 between redundant processing centers140,142 may be omitted from theprocessing center20 of FIG. 1 in which thesingle processing center20 supportsmultiple collection devices14a-14n.
• As noted above, the communication links[0063]134a-134nbetween a collection device and the processing centers may take various forms. FIG. 5 shows two illustrative communication link forms, one labeled164aand the other labeled164b. Communication link164ais provided by a voice T1 line coupled to aPortmaster166 and communication link164bis provided by POTS lines coupled to amodem bank168 which is controlled by aremote access server170. ThePortmaster166 is available from Lucent Technologies and contains modems used to demultiplex the 24 multiplexed voice lines comprising theT1 line164a. Use of either or both types ofcommunication links164a,164bis suitable for coupling the processing center to a plurality of collection devices through thepublic phone system162.
• The[0064]Portmaster166 is coupled to a File Transfer Protocol (FTP)server176 through a non-routable hub174 (i.e., a hub that has no further connections beyond those shown in FIG. 5). Theremote access server170 is coupled to theFTP server176 through a non-routable network interface card (NIC)190a(i.e., a network card which sees no further network connections beyond those shown in FIG. 5). As will be described further in connection with FIG. 6, a compressed data file containing physiological data is transmitted from a collection device to theFTP server176 for temporary storage prior to analysis. Also, results files containing test results generated at the processing center are placed on theFTP server176 for downloading to a collection device. In the illustrative embodiment, theprocessing center20 implements the TCP/IP protocol on an Ethernet network.
• A[0065]traffic cop server178 implements a database management routine by which theFTP server176 is monitored for unanalyzed physiological data files and the data files on theFTP server176 are decompressed and placed in adatabase server180 through anon-routable NIC190bto await analysis. The traffic cop application also monitors thedatabase server180 for analyzed tests so that it can generate results files, compress the results files and place them on theFTP server170 for downloading by the respective collection device. In the illustrative embodiment, thetraffic cop server178 is implemented on a standard Intel x86 compatible server running Windows NT.
• The[0066]database server180 contains the physiological data from the collection devices and, after analysis, the test results generated in response to the physiological data. In the illustrative embodiment, thedatabase server180 is implemented with Oracle relational database management system (RDBMS) on a Sun Microsystems Ultra server running the Solaris operating system.
• A plurality of[0067]analyst workstations184a,184b, . . .184nare coupled to thedatabase server180 and are used by trained analysts to process physiological data and provide test results. The workstations184a-184ntake unanalyzed data from thedatabase server180 for analysis, as will be described further in connection with FIG. 8. The test results provided by the analysis are packaged by thetraffic cop server178 and placed on theFTP server176 for downloading by the respective collection device.
• In the illustrative embodiment, the[0068]remote access server170 ofprocessing center140 implements additional functions including that of a file server, archive server and backup server. According to its file server functionality, theserver170 contains the analysis software executed on the analyst workstations184a-184n, as well as other files shared by processing center components. As a backup server, theserver170 periodically creates a snapshot of the data in thedatabase server180 and the software files in the file server portion of theserver170 in order to permit restoration of data if software files are lost. Data which is not necessary for long-term use (e.g., raw physiological data received from collection devices) is periodically moved to the archive portion of theserver170. In the illustrative embodiment, only theserver170 at one of the processing centers140,142 provides backup functionality since the replication of data at bothprocessing centers140,142 would make backup at both processing centers unnecessarily redundant.
• As described above, each of the processing centers[0069]140,142 is coupled to the other withredundant communication links148,150, as shown. More particularly, each processing center includes arouter182 for coupling thelinks148,150 to ahub172 for further coupling to thedatabase server180 andremote access server170 throughroutable NICs190c,190d, respectively, as shown. Thehub172 may be coupled to a further network160 (FIG. 4).
• In the illustrative embodiment, one of the[0070]links148 is implemented with a data T1 line and theother link150 is implemented with a data ISDN line, as shown. Thelinks148,150 are provided primarily to permit physiological data and test results to be replicated and stored at both sites periodically (e.g., every minute). In the illustrative embodiment, data replication (i.e., synchronization) is achieved using the Advanced Replication feature of Oracle 8i Enterprise Edition referred to as Multimaster Replication running on the traffic cop server. As noted above, preferably the twolinks148,150 are provided by different carriers in order to mitigate failures due to equipment trouble or clerical error.
• A[0071]time server186 is provided for maintaining a master clock with which the time clock maintained in the collection devices132a-132ndialing into theprocessing center140 can be synchronized. Use of the time server facilitates process time data collection. For example, the time that it takes the processing center to process physiological data and the collection device to download the test results can be monitored.
• Referring also to FIG. 6, a flow diagram shows an illustrative process by which raw physiological data is transmitted from a collection device to a processing center. The flow diagram more specifically illustrates data transmission from a collection device[0072]132a-132nto one of two redundant processing centers140,142. However, the process is substantially similar to that implemented by a collection device in communication with only one processing center (FIG. 1), with the exception that steps204 and280-288 would be omitted as will become apparent.
• The process commences in[0073]step200 with the operator of the collection device providing an input to transmit data, following which the collection device processor26 (FIG. 2) randomly selects one of the twoprocessing centers140,142 for connection instep204. Instep208, a remote access connection is established by the collection device modem38 (FIG. 2) to the selected processing center. Instep212, it is determined whether the connection has been established.
• If the connection has been established, then the time on the collection device is synchronized to the time maintained by the processing[0074]center time server186 instep216, following which the collection device is coupled to theFTP server176 instep220 in response to input of a valid user name and/or password instep222. The RAS and FTP connections to the processing center remain open until the physiological data transferred to the processing center is analyzed and returned to the collection device in the form of a results file. In the illustrative embodiment, from the time physiological data transmission begins until the results file is transmitted back to the collection device takes on the order of 5 minutes.
• In[0075]step224, it is determined whether a connection to theFTP server176 has been established. If the connection has not been established, then the operator is notified instep290 that the session data must be sent to the processing center later. Alternatively, if the connection is established, then a compressed data file is created instep228 for uploading to theFTP server176, such as may be created by using industry standard PKZip compatible compression. The Zip file includes patient information from the Patient's table100 (FIG. 3), with the exception of the patient's name and other patient identifying information, for patient confidentiality purposes. The Zip file further includes session information from the Sessions table102, test information from the Tests table104, and performance and physiological data from whatever tests were performed. For example, for the Valsalva test, the Zip file includes the breath pressure data and ECG data. And for the metronomic test, the Zip file contains the breath volume data and the ECG data. The Zip file is also time stamped with the time uploading of the file starts. Creation of the Zip file requires input of the collection device ID (i.e. a unique identifier of the collection device) and a session ID (a unique identifier of the session), as shown at230 and232, respectively.
• In[0076]step234, it is determined whether a results file having the transmitted collection device ID and session ID already exists on theFTP server176, as might occur if a connection is lost after physiological data is transmitted to the processing center and before a results file is returned to the collection device. If such a results file exists, then it is downloaded by the collection device instep238. Alternatively, the Zip file created instep228 is uploaded to the processing center instep242 and placed on theFTP server176.
• It is next determined, in[0077]step246, as part of the FTP protocol, whether or not the Zip file was uploaded successfully. If the Zip file was not uploaded successfully, then the operator is notified instep290 that the session data must be transferred later, as shown. Alternatively, thetraffic cop server178 repeatedly looks on the FTP server for a results file corresponding to the uploaded session data in theloop including steps250,254, and246. Once the results file is found instep254, the results file is downloaded to the collection device instep238.
• Following downloading of the results file to the collection device, the results file is deleted from the[0078]FTP server176 instep258 and the connection to theremote access server170 is closed instep262. Instep266, data from the results file is placed into the collection device database (FIG. 3) and a report is printed at the collection device instep270. Once the operator presses a “done” button instep272, the collection device returns to a main menu instep274. The collection device main menu provides the operator with options to enter patient demographics, view a help system, begin clinical testing, perform system setup procedures, or power off the device. Also, if at any time the operator presses a “send later” button (step278), the device also returns to the main menu instep274, as shown.
• If, in[0079]step212, a connection was not established to the processing center selected instep204, then the other processing center is selected instep280, following which the remote access connection to the newly selected processing center is established instep284. If it is determined instep288 that the connection has been established, then step216 is next performed, as shown. Alternatively, if a connection to the newly selected processing center cannot be established, then the operator is notified, instep290, that the session data must be sent later.
• Referring also to FIG. 7, an illustrative format for the[0080]processing center database350 on the database server180 (FIG. 5) is shown. In the illustrative embodiment, thedatabase350 is an Oracle8i enterprise edition. However, it will be appreciated by those of ordinary skill in the art that various database packages may be used. Thedatabase350 includes a Remote Sites table300 which contains information about the different medical facilities at which collection devices132a-132nare located, such as facility description, name, contact person, address, etc. For each entry in the Remote Sites table, there may be one or more entries in a Remote Units table304 for each collection device132a-132nlocated at the particular remote site. A collection device, or remote unit is identified, in the illustrative example, by a site ID, a unit name, and a description of the device.
• A Patients table[0081]302 contains patient demographic information about each patient for whom data is stored and identifies the patient by the Patient_id only. Patient table entries are processed to provide entries in a Demographics table306 which is used to collect trending data separate from the individual patient data.
• Each entry in the Patients table[0082]302 has one or more entries in a Sessions table308 depending on how many test sessions, each including one or more tests performed on the patient, were conducted for the particular patient. The Sessions table308 contains information describing the test session including, but not limited to the Patient_id, the date, the start and stop times of the session; the date that the collected physiological data is transmitted to the processing center, whether the data has been analyzed and if so, when analysis occurred. Each entry in the Sessions table308 has one or more corresponding entries in a Tests table310 according to how many tests are performed during the given session. The Tests table310 contains data types common to each of the tests performed in the respective session.
• Also provided are tables corresponding to each of the types of tests performed by the collection devices which include, in the illustrative embodiment, a Valsalva table[0083]312, a Metronomic (E/I) table316 and a Stand table320. Each entry in the Tests table310 has a corresponding entry in one of the Valsalva table312, the Metronomic table316, and the Stand table320 once the test results are returned to the collection device.
• Each of the processing center database tables[0084]308,310,312,316, and320 is substantially identical in content to collection device database tables102,104,110,114, and118 of FIG. 3, with the exception that certain processing center tables additionally contain an identifier of theprocessing center140,142 which originally inserted the particular record (originsite_id) and an identifier of the last processing center to update the particular record (lastupdatesite_id). Also, theprocessing center database350 contains an Analysis Site table330 containing an identifier of the processing center at which the database is located (analysissite_id), as shown.
• As noted above, since physiological data is replicated and stored at both[0085]processing centers140,142, either processing center can analyze the data. However, under normal operating conditions, the processing center to which the data was initially transmitted will analyze the data, as will be described further in connection with FIG. 8. Whether a particular processing center initially received the data is determined by comparing the originsite_id associated with data awaiting analysis to the analysissite_id. A match between these values indicates that the data was originally sent to the particular processing center.
• For diagnostic reasons, it is desirable to be able to track tests for which the data was originally sent to one of the processing centers, but was analyzed at the other processing center. If the originsite_id is different than the lastupdatesite_id, then it can be inferred that the physiological data was originally sent to one processing center, but was analyzed or modified by the other.[0086]
• An Acceptance Criteria table[0087]334 is provided for storing predetermined test acceptance criteria with which a decision is made by the processing centers140,142 as to whether or not to accept or reject particular test results, as is described below in conjunction with FIG. 8. In the illustrative embodiment, the Acceptance Criteria table334 contains, for the metronomic test, the minimum and maximum E/I ratios, the minimum and maximum average breath amplitudes, and the minimum and maximum average breath frequency. For the Valsalva test, the Acceptance Criteria table334 contains the minimum and maximum Valsalva ratios, the minimum and maximum average expiration pressures, the maximum standard deviation of expiration pressure, and the minimum and maximum duration of the Valsalva maneuver. For the stand test, the Acceptance Criteria table334 contains the minimum 30:15 ratio (i.e., the minimum ratio of the highest heart rate within a first duration after standing, such as 15 seconds, to the lowest heart rate within a second duration after standing, such as 30 seconds) and the maximum 30:15 ratio (i.e., the maximum ratio of the highest heart rate within a first duration after standing, such as 15 seconds, to the lowest heart rate within a second duration after standing, such as 30 seconds). The table334 further contains the maximum percentage of splined heart rate which represents the maximum percentage of the heart rate signal that may be splined.
• Raw physiological data in the form of ECG data is stored in an ECG Data table[0088]338 and an Errors table324, similar to the Error table120 of FIG. 3, is provided for storing information about rejected tests. A further, Rejection Reasons table332 includes an entry for each reason for rejecting a test. Finally, thedatabase350 contains an Other Data table336 in which test performance data (e.g., breath rate, etc.) is stored. Also provided in theprocessing center database350 is an optional Baseline table326 in which baseline ECG data may be stored (i.e., an ECG signal measured prior to testing). Although not shown in theprocessing center database350 of FIG. 7, the processing center database may include tables (similar to tables124 and126 of the collection device database) in which blood pressure data is stored in applications in which the heart rate monitors are equipped with a blood pressure acquisition device.
• Referring also to FIG. 8, a flow diagram shows an illustrative process by which an analyst at a workstation[0089]184a-184n(FIG. 5) analyzes physiological data and provides corresponding test results. The process of FIG. 8 is implemented by each analyst workstation184a-184nin each of the redundant processing centers140,142 of FIG. 4. However, the process is substantially similar to that which is implemented on an analyst workstation in the single processing center embodiment of FIG. 1, with any exceptions noted below.
• The process commences in[0090]step450, following which a main menu is displayed to the analyst instep452. From the main menu, the analyst can power off the program atstep454, view a “queue screen” instep456, or analyze test data, beginning atstep458.
• The queue screen presents a list containing information about all of the tests currently awaiting analysis. The analyst may use this screen to select a specific test for analysis. In the case where the process of FIG. 8 is implemented on one of redundant processing centers[0091]140,142, the queue screen may list only those tests intended for analysis at the particular site (i.e., those tests having an originsite_id matching the analysissite id of the particular processing center). Alternatively, the queue screen may list all unanalyzed tests, with an identifier of the processing center to which the test data was originally sent. Under normal circumstances (i.e., when bothprocessing centers140,142 are functional), each processing center analyzes data that is initially transmitted directly to the particular processing center. This arrangement prevents conflicts in which both processing centers analyze the same data. However, if one of the processing centers is down, then all of the tests awaiting analysis can be analyzed at the operational processing center. For example, as described above, if one of the processing centers receives physiological data but is unable to analyze it, then the operational processing center analyzes the received data.
• Analysis commences in[0092]step458, either directly from the main menu or from the queue screen. In the illustrative embodiment, in which the collection devices are heart rate monitors used to analyze a patient's heart rate variability, the analysis performed at the processing center involves manipulation of raw ECG data in order to enhance the detection of R-waves and thus, the accuracy of test results which are based on accurate measurement of R-R intervals between R-waves.
• The R-wave detection screen displayed to the analyst in[0093]step458 presents a graphical display of the raw ECG data. Superimposed vertical markers indicate R-wave events as detected by a rigorous R-wave detection scheme of the type described in U.S. Pat. No. 5,984,954, entitled “Methods and Apparatus for R-Wave Detection,” which patent is incorporated herein by reference in its entirety. The analyst may actuate user inputs to add or remove R-wave detections. For example, some of the displayed R-wave detections may be so close to each other as to suggest that noise., rather than a peak of the QRS complex triggered the detection. In this case, the analyst may delete one or more such detections. Also presented on the R-wave detection screen is a graphical display of heart rate versus time that is updated dynamically as the analyst adds or removes R-wave detections.
• Once the analyst has added and removed R-wave detections as necessary, a heart rate splining screen can be displayed in[0094]step460 from which the analyst can modify the heart rate versus time waveform by a technique referred to as splining. Splining is a process by which heart rate variations which are likely to be false based on some criteria are ignored and the heart rate versus time signal is smoothed by bridging the gap across such variations. This screen presents a graphical representation of the heart rate versus time waveform, with a graphical representation of the splined heart rate versus time signal superimposed on it. In the illustrative embodiment, the analyst may vary the following splining parameters: maximum heart rate change, maximum heart rate, and minimum heart rate. The analyst may update, or refresh the graphical representations as parameters are changed.
• Once R-wave detections on the ECG signal are edited in[0095]step458 and the heart rate waveform is edited instep460, a final analysis screen may be viewed instep462 on which test results and other data are displayed. The final analysis screen is different for each of the autonomic nervous system tests. In the illustrative embodiment, the final analysis screen provides an indication of any test results which do not fall within predetermined acceptable limits (i.e., acceptance criteria) which are stored in the Acceptance Criteria table334 of the processing center database350 (FIG. 7). For example, illustrative E/I test limits and Valsalva test limits are between 1.00 and 4.00.
• In the case of final analysis for the metronomic test, the screen presents a graphical display of the heart rate versus time, splined heart rate versus time, and inspiration volume data. The extent to which the heart rate data was splined is displayed as a percentage. The analyst is presented with the calculated results of the current test. In one embodiment, a top grid of the results displays the time and amplitude of each heart rate peak and trough used for analysis and a bottom grid displays the E/I Ratio (average of the peak heart rates divided by the average of the trough heart rates), Average Breath Amplitude, Average Breath Standard Deviation and Average Breath Frequency.[0096]
• In the case of the Valsalva test, the final analysis screen presents the analyst with a graphical representation of the heart rate versus time, splined heart rate versus time and expiration pressure data from the current test. The final analysis screen also presents the analyst with the calculated results of the current test. For example, a top grid of the results displays the start time (r1) of the Valsalva maneuver based on the first expiration above a predetermined level, the stop time (r2) of the Valsalva maneuver based on the last expiration above the predetermined level, the maximum heart rate during the Valsalva maneuver (hmax) and the minimum heart rate during a recovery period following the Valsalva maneuver (hmin). The bottom grid displays the Valsalva Ratio, Duration of Maneuver, Average Pressure and Standard Deviation of Maneuver.[0097]
• Following the final analysis of[0098]step462, the analyst may attempt to accept or reject the particular test instep464. If the analyst attempts to accept the test, then it is determined instep468 whether an acceptance criteria check has been passed. The acceptance criteria check refers to an automated determination of whether the test results fall within predetermined acceptable limits stored in the Acceptance Criteria table334 of theprocessing center database350 of FIG. 7 (i.e., the same process which is performed prior to displaying test results from the final analysis screen).
• If the test results pass the acceptance criteria test, then the results are placed on the database server[0099]180 (FIG. 5) and the test is marked as analyzed in the analysis queue instep470, following which the main menu is displayed instep452, as shown. Alternatively, if the test results do not pass the acceptance criteria test, then the routine displays the final analysis screen again instep464 with an indication of the invalid results. In particular, the test result values which are outside of the predetermined acceptance limits are highlighted. In this way, if the final analysis screen indicates a rejected test based on non-compliance with the predetermined acceptance limits, the analyst cannot override this determination and accept the test. Thus, the test is rejected instep464.
• Following rejection of a test in step[0100]464 (either by analyst choice or by non-compliance with the predetermined acceptance limits), a reject test screen is displayed instep466. This screen gives the analyst the option of viewing a rejection reason screen instep474 for the purpose of documenting the reason for rejecting the test results. Instep472, the rejected test is marked as an error (i.e., placing the rejection reason in the Error table324 of the processing center database350 (FIG. 7)), following which the main menu is displayed instep452.
• Having described the preferred embodiments of the invention, it will now become apparent to one of ordinary skill in the art that other embodiments incorporating their concepts may be used.[0101]
• It will be appreciated by those of ordinary skill in the art, for example, that the format of the databases at the heart rate monitors and processing centers are illustrative only and could be readily varied.[0102]
• Likewise, the software executed at the collection devices for transmitting physiological data to a processing center (FIG. 6) and at the processing centers for analyzing the data to provide test results (FIG. 8) could be varied without departing from the spirit of the invention.[0103]
• It is felt therefore that these embodiments should not be limited to disclosed embodiments but rather should be limited only by the spirit and scope of the appended claims. All publications and references cited herein are expressly incorporated herein by reference in their entirety.[0104]

Claims (19)

What is claimed is:

1. A heart rate variability system comprising:

a plurality of heart rate monitors, each located at a medical facility and operable to collect physiological data of a patient from which heart rate variability can be assessed; and

a processing center located remotely from, and in communication with said plurality of heart rate monitors, wherein said processing center is adapted to receive said physiological data from each of said plurality of heart rate monitors and to analyze said physiological data to provide results of one or more tests based on the patient's heart rate variability and indicative of the patient's autonomic nervous system function.

2. The heart rate variability system ofclaim 1 wherein each of said plurality of heart rate monitors is in communication with said processing center through at least one of a POTS line and a T1 line.

3. The heart rate variability system ofclaim 1 wherein said processing center includes:

a processor on which an R-wave detection routine is implemented; and

a user interface adapted to receive an input from an analyst by which R-wave detections are added or deleted.

4. The heart rate variability system ofclaim 3 wherein said user interface is further adapted to receive an input from said analyst by which a heart rate variability waveform generated in response to said detected R-waves is modified.

5. The heart rate variability system ofclaim 1 wherein each of said heart rate monitors comprises a display for displaying a waveform showing the breathing performance of said patient during collection of said physiological data and standards against which to compare said waveform in order to determine the extent to which said patient followed a predetermined breathing regimen during collection of said physiological data.

6. The heart rate variability system ofclaim 5 wherein each of said plurality of heart rate monitors includes a user interface adapted to receive an input from an operator by which said physiological data of said patient is accepted or rejected, wherein only accepted physiological data is transmitted to said processing center for analysis.

7. The heart rate variability system ofclaim 6 wherein said physiological data of said patient is rejected by said operator if comparison of said waveform to said standards reveals greater than a predetermined deviation between said waveform and said standards.

8. The heart rate variability system ofclaim 6 wherein said physiological data of said patient is accepted by said operator if (a) comparison of said waveform to said standards reveals less than a predetermined deviation between said waveform and said standards; or (b) comparison of said waveform to said standards reveals greater than a predetermined deviation between said waveform and said standards and said acceptance is based on a request by said operator for feedback from said processing center.

9. The heart rate variability system ofclaim 1 wherein said processing center is further adapted to transmit said results to the one of said plurality of collection devices at which said physiological data is collected.

10. The heart rate variability system ofclaim 1 wherein said processing center is further adapted to compare said results to predetermined acceptance criteria and to reject said results if said comparison reveals greater than a predetermined deviation between said results and said predetermined acceptance criteria.

11. A medical testing telemetry system comprising:

a plurality of collection devices, each one located at a medical facility and operable to collect physiological data of a patient, wherein each of said collection devices comprises:

a display for displaying a waveform showing the patient's performance during collection of the physiological data and standards against which to compare said performance waveform in order to determine the extent to which said patient followed a predetermined breathing regimen during collection of the physiological data; and

a user interface adapted to receive an input indicating acceptance of said physiological data if said comparison reveals less than a predetermined deviation between said performance waveform and said standards or indicating rejection of said physiological data if said comparison reveals greater than a predetermined deviation between said performance waveform and said standards; and

a processing center located remotely from, and in communication with said plurality of collection devices, wherein said processing center is adapted to receive said accepted physiological data from each of said plurality of collection devices and to analyze said physiological data to provide a test result.

12. The medical testing telemetry system ofclaim 11 wherein each of said collection devices is a heart rate monitor adapted to collect physiological data from which the patient's heart rate variability can be assessed and wherein said test is selected from the Valsalva test, the E/I test, and the standing test.

13. The medical testing telemetry system ofclaim 12 wherein said performance waveform shows breath pressure versus time when said test is the Valsalva test.

14. The medical testing telemetry system ofclaim 12 wherein said performance waveform shows breath volume versus time when said test is the E/I test.

15. A medical testing telemetry system comprising:

a collection device located at a medical facility and operable to collect physiological data of a patient,

a first processing center located remotely from, and capable of communication with said collection device wherein said first processing center is adapted to receive said physiological data of the patient and to analyze the physiological data of the patient to provide a test result based on the physiological data; and

a second processing center located remotely from, and capable communication with said collection device, wherein said second processing center is adapted to receive said physiological data of the patient and to analyze the physiological data of the patient to provide a test result based on the physiological data.

16. The medical testing telemetry system ofclaim 15 wherein said collection device comprises a processor which randomly selects one of said first and second processing centers to analyze said physiological data of the patient.

17. The medical testing telemetry system ofclaim 15 wherein said first and second processing centers are interconnected.

18. The medical testing telemetry system ofclaim 17 wherein said first and second processing centers are interconnected by a plurality of communication links.

19. The medical testing telemetry system ofclaim 15 wherein said first and second processors are further adapted to transmit the test result to said collection device at which said physiological data is collected.

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