8/3/2019 01182949

1/6

CARDIOSMART:Intelligent Cardiology Monitoring System Using G PSlGPRS NetworksM. Elena, J.M. Quero, S.L.Toral, C.L. Tarrida, J.A. Segovia, L.G. Franquelo

Dpto. de Ingenieria E le ctr hi caEscuela Superior de Ingenieros.Camino de 10s Descubrimientos sln 41092Universidad Sevillamar@gte.esi.us.es

Abslmd -Cardiosmart project is based on B eortable terminal for the-cquisition, pre-processing and transmission of Cardiac signalsand th e GPRS network (PA C) used to send the ECG signal to ahost computer i n the medical services provider centre or aspecialist consulting room. T he PAC terminal includes a GPRSmodem for data transmission, a GPS device to provide anaccurate location of the patient, and an intelligent heartpathology detection system.The objective of this project consists of the development of aEuropean Cardiology On-line Monitoring System usingGPRSIGSM w ireless comm unication technology. The utilisationof electrocardiogram transmission will improve efficiency ofmedical care and service fo r patients if they could be monitoredconstantly by health care providers. A direct and alm ost instantmedical support is provided, specially to those patients thatvanish during the heart attack.This work has been funded by the European Comission IST-2001-35073.Keywords- GPRS, ECG (Electrocardiogram), SMT (SurfaceMount Technologv), PAC (Qortable terminal fo r the-cquisition, pre-processing and transmission of cardiac),packets, protocol.

I. INTRODUCTIONActual cardiology monitoring systems are improved interms of storage capacity or autonomy. But new mobilecommunications technology is opening new ho rizons for newideas that will improve the quality of life of patients[l-2].Portability and autonomy are concepts very close to actualmobile communications. So the junction of this concepts ledto new applications that could not be exploited some monthsago.T o our best knowledge, it is the first time that a portable

terminal fo r the acquis ition, pre-processing and transmissionof cardiac signals (PAC) allow s the continuous detection andon-line GPRS data transmission in cardiology environment.Previous researches has been oriented following thisperspective during last few years. The first system productdeveloped allowed the patients to transmit their ECG to a 24-

0-7803-7474-6/02/$17.00 82002 IEEE

hour duty medical centre. This system also includes a QRSdetection algorithm for automatic syncope detection withoutthe participation of the patient [3].Next step consisted of using the new GSM transmissionpossibilities. A prototype including a GSM data modem has

been developed and it has been proved that concept wastechnically feasible. Nevertheless, despite of thetechnological evolution, communication infrastructure andadvanced hardware needed for complex high-qualitytelemedicine services, they remain very expensive. GSMtransmission cost is related with time of connection, leadingto a very expensive continuous monitoring system. Also thepower consumption of a continuous GSM data transmissionled to a very reduced autonomy.

The main conclusion of these experiences was thenecessity of joining together portable equipment, continuousmonitoring system, power consumption, cost o f transmissionand optim isation of the amount of data to be transmitted.

Our proposed solution to solve the transmission problemis the use of the GPRS network [4]. This novelcommunication protocol is going to allow a non expensivetransmission and a cost related with the amount of datatransmitted (the user is going to pay the amount of datatransmitted, independent of the connection time). Moreover,GPRS provides a bandwidth minimum of 64 Kbytes.An additional improvement consists of reducing theamount of data to transmit, taking into account that themajority of the monitored information is a normal ECGsignal. Nevertheless, the interesting information for thespecialist is just the abnormal ECG signal. Instead of doingthe signal processing after the transmission, it will he donebefore. If we combine an intelligent detection system withdata compression of information, the amount of data is notonly reduced but also optimised [5-61.The main technical problems to be so lved are:

1. To guarantee the reliability of the components andcommunication channel. Design, manufacturing and

3419

8/3/2019 01182949

2/6

2.

3.4.

5 .

validation of this medical device must comply withmedical specifications and obtain European certification.To achieve electromagnetic compatibility between theSignal Conditioning Module and the CommunicationModuleTo obtain maximum autonomy (at least, 24-hour)minimising power consumption.To reduce the manufacturing and functioning cost at aminimum, making new technology accessible to anysocial level.To achieve a minimum size and weight to guaranteeuser's acceptability.

.

Figure 1.A block diagram of network

In this paper the development of a new terminal (PAC)with portability, autonomy, signal acquisition and digitalprocessing, data compression and encryption, and a GPRSlink is suggested. GPRS modem provides a data channel andalso a GSM voice channel for the direct communicationbetween patient and specialist. ECG information istransmitted to a host computer with a database, so thespecialist will diagnose and p ropose actions to the patient. Italso allows a continuity of care, even if the patient isgeographically far from the cardiologist. [7]. t consists of theintegration of three critical blocks in just one device: anelectrocardiograph, an efficient digital processing block anda GPRS/GSM modem. I f the medical center cardiologistneeds information, he will connect to the medical center totransmit the recorded ECG without the attention of thepatient.

Besides, automatic pathology detection is included beforethe transmission. The idea of this ECG pre-processor is toreduce the amount of data transmitted. Instead of acontinuous link with the specialist in which the majority ofthe information is useless, only the problematic ECG istransmitted.

11. TELEMEDICAL NETWORKA block diagram of the whole system is showed in Figure

1. It is a basic scheme of the cardiology network based on the

PAC term inal, the host center and internet accessThe m ain components in the system are:

I .

2.

3.4..

A portable data-acquisition console (PAC), is connectedto every patient in the network and will transmit theECG.A medical service provider (MSP) uses another GPRSmodem to allow communication from several PACs,using only the telephony network to preventuncontrollable Internet delays.A communication protocol over GPRS is used totransmit a continuous ECG with a minimum delay.A GS M voice channel is used to allow a doctor toestablish a direct call with the patient.An internet access to a database host center allowspatient monitoring from an authorised European hospitalor private doctor.

The system will work as an on-line mobile telemedicalsystem, providing autonomy to the patient and real-timecardiac disease diagnostic. Besides, patients require anintelligent system capable of detect heart pathologies, inwhich they must not be worried about the moment intransmitting the electrocardiogram (ECG) to the specialist.They claim for an automatic detection of the heartdysfunction and the subsequen t transmission to the do ctor.

From the functional point of view, patients will bemonitored using a PAC from any hospital of the network intwo modes:1. Continuous mode. ECG signal i s continuouslytransmitted to the host center and monitored from ahospital.Intelligent mode: Once the processor has detected anabnormal heart activity, it automatically connects with

the medical centre to transmit the information.Request mode. A hospital could activate a PAC at anytime to receive the ECG of a particular patient.

2.

3.

A ) Porta ble Dala-Acauisition Console /PAC1

Figure 2. A block diagram of PAC

3420

8/3/2019 01182949

3/6

A block diagram of the PAC terminal is showed in Figure2. It must be a portable equipme nt of small size to allow a 24hour connection of the patient with the followingsubsystems:1. ECG Conditionine Module: Consisting of three or ten

electrodes attached to standard patches, amplificationand filtering stages. Special instrumentation amplifiersare chosen from previous design s.Simal Processing Module: To implement the wholedigital processing stage in cluding data conversion, heartrate detection, pattern recognition, compressionalgorithm and signal cryptogra phy.GPRS M odule: Including a data and a voice channel forthe direct communication between the patient and thecardiology specialist.GPS Module: To provide the exact location of thepatient.Power Module: To supply the power to all modules withminimum energy consumption.

2.

3.

4.5 .

The previous GSM prototype integrates an 8-bitmicrocontroller. In this proposal the use of a 32-bitmicrocontroller from the MCORE Motorola family issuggested. This microcontroller includes all necessaryhardware (RAM and Flash memories, coprocessor, Digitaland Analog IiO signals, low-power modes...) to fulfil allelectronic requirements i n this applications.This wireless link is both voice and data GPRSiGSMinterface. The communication is bi-directional: the ECGcaptured can be transmitted to the medical center, and directcalls may he establish from the host. As the voicecommunication interface of the modem is available, amicrophone and a loudspeaker has been included. All theintegrated circuits used have the possibility of a shutdown

mode, to save battery.E ) SignalFrocessing Module

Because of the automatic recognition of heart failure is ademand o f the patients for im proving their quality of life, thedigital processor must implement several ECG pre-processing steps. They are illustrated in Figure 3.A QRS detector must he implemented for the heart ratecalculation. Sup raven tricu lar tachycardia, bradycardia andsyncope diagnoses are based on this algorithm [8]. It must betaken into account the noise interference due to theelectronics and the GPRS modem. A neural networks fo rpattern recognition t echn ique s will classify the different kind

of beart diseases: blocks, flutter, atrial and ventricularfibrillation and supraventricular and ventricular scape, bycomparison with the normal ECG.As GPRS cost is related with the amount of data, acompression algorithm based on wavelets is going to beimplemented. They have been demonstrated to be very

efficient to reduce the number of packets transmitted (meancompression ratios up to 8.1 in GS M network). The last taskof the processor is the encryption of the ECG signal, becausenational and international regulations force the privacy ofthis personal information.At last, the final algorithm will be tested usinginternational biomedical databases (i.e. MIT-BIH).

C) Medical Service Provider An d Host CenterThe communication system module is used to connect thehost with o ne PAC at a remote location. The database systemmodule saves the patient records along with their ECGs andother relative information such as clinical treatment,symptoms, etc. The schema of the database includes all th efields that requires at the appropriate format. Its opendatabase architecture helps its adaptation from largedatabases which can use it as a telemedicine gateway to oth er

systems located at rural or isolated areas. This module feedsthe comm unication system and the PAC modules with ECG sand patients data. A direct and almost instant medical supportis provided, as a voice channel is included in the GSMconnection . A 24-hour duty service detects rapidly cardiacdiseases in advance.

Figure 4. A on-line electrocardiogram

3421

8/3/2019 01182949

4/6

Additionally, the host computer implements an internetsite, so the information can be consulted from hospitals orother specialists, even if they are far from the host computer[ 9 ] . The system including the portable terminal plus a host

computer with external access may become a completecardiology network. A RS-232-C serial communication linkis needed to provide communication with a persdnalcomputer. Figure 4shows anECG signal transmitted on-line.

: UMTS Application

GPRS

TerminalMobile

MobileApplication

GPRS

IP Tunnel

Figure 5. GPRS CommunicationProtoeol

0) PRSProfocolThe implemented GPRS protocol is showed in previousfigure (Figure 5 ) , where communication is established

between the patient portable terminal (PAC) and themedical service provider center (MSP). In the high levelthere is an application layer transparent to user. Thisapplication depends on the medical informationrequirements and data normalization, maintaining acontinuous data transmission in a high quality.The data packets size depend on the mobile provideran d GPRS technology to guarantee an on-linecommunication, based on protocol implementationstandards. Our prelim inay probes establish a data packetsof 1500 bytes as maximum, depend on the transmittedmessage. This packets have attached an errors detectionand correction algorithm to each side of communication.After using a data-packets order number and an useridentifier, a sliding window protocol allows informationrecuperation. Once establishment phase has finished, anoriented-connection protocol is used due to needs ofinformation veraciously.

IV. ROTOTYPEA prototype including a GPRS/GSM data modem (seeFigure 6 ) has been developed and it has been proved that

concept was technically feasible. This prototype have notstill included intelligent mode.

Figure 6.A prototypephotoofPAC

3422

8/3/2019 01182949

5/6

From the electronic point design of view (Figure 7) , the validated with a 99.5% pulse detection succeed during themost critical task has been the integration of an validation process. Th e feedback information from theelectrocardiograph and the data modem. Special care has medical center has demonstrated that the algo rithmbeen taken in order to minim ise the electromagnetic implemented is well suited for the majority of patients.interference that a power RF stage can exert on anelectrocardiograp h that am plifies signals in the range ofmV. This goal has been achieved designing a specialshielding scheme to avoid ECG distortion. V. FUTURE WORKS

To improve the quality of the signal, a SO Hz otch filterhas been implemented. Power line interference is the mainsource of noise. Common mode rejection ratio of thedifferential amplifier, the antialiasing low pass filter andthe band reject filter digitally implemented avoid thecorruption of the ECG signal.The integrated modem is a product with a SIMconnector as well as a standard RF connector type MMCX(Miniature Micro Connector).Board dimensions are (in mm) 81 * 5 5 and the weight is

The main target of this project is improving the qualityof life of cardiology patients, as they have not to beconfined in hospitals. They will feel free of walking oreven travelling but keeping contact with their cardiologyspecialist or hospital. A direct and almost instant me dicalsupport is provided, as a voice channel is included in th eGPRS connection.Basically, this general objective will be achieved bymeans of the following detailed measurable objectives:1. Selection of algorithms for QRS detection andpattern recognition, according to the standardsdefined in hiomedical s im al databases. T h e esult~~ 1~~~~~ ~~~.

approxim ately as a mobile phone. T he battery sup ply is 3. 6 must be to detect the maximum number ofV and the prototype power consumption is 275-300 mA pathologies.during packets transmission, descending to 20-25 mA in 2. Selection of algorithms for compression andidle state. Each IS seconds, a new data packet is built and cryptograph y. The result must be to optimise thesent in real time, with 2 or 3 second s duration time. The amoun t of data transmission.sampling rate is 360 Hz . One of the objectives in the project is to determine astandardization of this kind of on-line ECGs, defining theminimum requirements for their transmission. This

L-

objective will b e setting a Spanish GPRS network duringthe first year, with the collaboration of some hospitals andspecialist.This system will also set up a novel collaborativeenvironment to share data for continuity of care. Thequality of telemedicine services must be kept at high

standards. Additionally, telemedicine services inelectrocardiography can be offered by keeping the cost inlow levels. So, we are working now in developing atechnology integration to provide the b est balance betw eenperformance and cost. The possibility of a GPRS/GSMsuppliers collaboration is able to locate the patients insideor outside o f buildings if emergencies appear.Not only the cost of the device is critical, but also theperformance of the compression algorithm, becau se it willdrastically decrease the volume of data and therefore thecommunication cost in GP RS.

Figure 7. A photo ofboard

Notice that the batteries used in this device must not becharged while it is being connected to the patient, and willhave to be substituted for their charge. To the hest of our knowledge, there is no a similarelectronic device cauable of using the current mobile

generation, although researches h a v e designed andsimulated an integrated mobile telemedicine syste m usingth e second generation of wireless network [21.GPS module will be optional in the final application, asit can be substituted by the information provided by thetelephony network.

The need of the data privacy and an efficienttransmission bandwidth is directing the study of dataencryption algorithms.Pulse detection algorithm has been tested for thesewaveforms with patients between 5 and 65 years old inorder to set the threshold values. These values has been

3423

8/3/2019 01182949

6/6

VI. CONCLUSIONSThe design and realisation of a novel intelligent andportable electrocardiograph device with a GPSIGPRS link(PAC) for monitoring the heart activity of patients and the

automatic detection and transm ission of fundam ental heartfailures have been proposed with restrictions of space andconsumption. The module comprises several subsystems:microcontroller system for data signal analysis,communication subsystem including GPRSMjSM standardlinks and power subsystem. This prototype can be usedautonomously, with the modem GPSIGPRS equipment.The main target of the prototype consist of providingcustomers a 24 hour me dical teleassistance service.The main risk of the project is to achieve a good balancebetween signal processing capabilities and powerconsumption, as, to our knowledge, there no exists anyintelligent cardiology portable device as the one proposedin this project in the market. Additionally, the host

computer could implement an Internet site, so theinformation will be consulted from hospitals or otherspecialists, even if they are fax from the host computer.The system including the portable terminal plus a hostcomputer with external access may become a completecardiology network that will improve the quality of life ofpeople.The experience achieved in this system could beextended to other medical specialties and other Europeancountries during the second year. The adjustments of thesystem to other countries in Europe will allow to extendthe initiative to the rest of the European Community andsetting up a novel collaborative environment to share datafor continuity of care.To summarise, the main innovation of the proposal isthe integration of a set of subsystems using newtechnologies, such us GPRS data transmission and GS Mvoice link, to solve the problems of cost and continuousmonitoring of the current cardiology devices. Thisprototype is medical asserting pending.

REFERENCES[ l ] 0. Ferrer-Roca, La Telemed icina: Situacidn Actual yPerspectivas, Fundacidn R etevision-Auna, Ed. 200[2] B. Woodward, R.H. Istepanian and C. Richards,

"Design of felemedicine system us ing a m obiletelephone", IEEE Transactions on InformationTechnology in Biomedicine , Vol. 5 , N". I , March2001, pp.13-15.[3] G.M. Friesen, T.C. Jannet, M.A. Jadallah, S.L.Yates,S.R. Quint and H.T. Nagle, A Comparison of NoiseSensivip of Nine QRS Detection Algorithm s, IEEETrans. Biomed. Eng., vol. 37, no. 1, pp. 85-98,Aug. 1990.[4] M.Elena, J.M. Quero, C.L. Tarrida and L.G. Franquelo,"Design of a mobile felecardiology sysfem usingGPRS/GSM Technology"EMBS 2002.

[5 ] Robert S.H. Istepanian and Arthur A. Petrosian,"Optimal Zonal Wavelef-Based ECG DaraCom pression fo r a Mobile Telecardiolo&y System" ,IEEE Transactions on Information Technology inBiomedicine ,Vol. 4, N". 3, September 2000, pp.200-211.

161 B.G. Celler and P. Chazal. "Low Computational costclassifiers for ECG diagnosis using NeuralNetwo rks", Proceeding of the 20" AnnualInternational Conference of the IEEE Engineering inMedicine and Biology, vol. 3, Nov 1998, pp. 1337-1340.[7] A Thanos, G Economakos, G Papakonstantinou, PTsanakas, L Nikolaidis, Y n Open System for ECGTelemedicine and Telecare",1999 pp. 1-4[SI J.W. Hurst and R.C. Schlant, The Heart, McGraw-Hill,Health Professions Division, Ed. 1990.[9] T. Penzel, B. Kemp, G. Klosch, A. Schlogl, J. Hasan,

A. Varri and I. Korhonen, "Acquisitionof Biomedicalsignals databases", IEEE Engineering in Medicineand Biology mag., Vol. 20, no . 3, MayIJune 2001, pp .25-32.

3424