march 2015 simulation of wearable ecg monitoring device...

International Journal of Engineering Trends and Technology (IJETT) – Volume 21 Number 2 – March 2015

ISSN: 2231-5381 http://www.ijettjournal.org Page 72

Simulation of Wearable ECG Monitoring Device

using MATLAB and J2ME Wireless Toolkit Madhur Gabhane

#1, Zahir Aalam*

2

#, *Department of Information Technology, Thakur College of Engineering and Technology, University of Mumbai, India

Abstract— Owing to an increase in the rate of cardiovascular

diseases, it is of utmost importance to provide appropriate

healthcare services to the masses in the form of wearable devices

that are wireless and work in a ubiquitous environment. The

simulation of one such wearable device is shown in this paper.

The device continuously monitors, ECG and if there is any

change in the ECG, sends MMS of the changed ECG to patient’s

mobile phone, which is interfaced to the hardware device via a

Bluetooth interface; and in turn, the patient’s mobile phone will

send that ECG image to a mobile phone at the hospital. The

purpose of this paper is to show simulation of this device using

MATLAB and Java 2 Micro Edition (J2ME) Wireless Toolkit

(WTK).

Keywords— Wearable Devices, Simulation, Mobile Phone,

MATLAB, J2ME WTK, ECG.

I. INTRODUCTION

Electrocardiogram (ECG) is a noninvasive tool widely used

for many years to perform basic cardiac monitoring in a

clinical set-up [1]. With advances in technology, the ECG

recording equipment are available in a smaller form factor.

Due to this improvement it is now practically possible to

develop wearable ECG (W-ECG) equipment for cardiac

monitoring in ambulatory conditions. This project uses the

patient’s ECG under normal conditions for initial setup, stores

this as a reference against which comparisons are made with

the real time ECG signals of the patient in a non-clinical setup

and finally, if any abnormality is found; this ECG plot is

stored digitally in the W-ECG equipment and is sent via

wireless transmission to the hospital.

With advancements in technology, it is now possible to

create wearable devices for Healthcare and diagnostics

purposes [2]. Technology can be introduced in the form of

wireless sensors to form a wireless communication network

that would widely help patients and healthcare professionals

by communicating data in a faster way thereby providing

mobility to the patient. One such device is an ECG

(Electrocardiogram) monitoring device [3]. The device

measures changes in the ECG of the patient, calculates the

change in the ECG parameters and change if any, notifies the

wireless mobile devices. The purpose of this paper is to show

simulation of this device, after which it would be rather easy

to construct the device for practical uses.

II. ARCHITECTURE

A. Description

The Block diagram shown in Figure 1 is the overall outline

of the system proposed. The system that is proposed consists

of three major modules, the hardware, the patient’s mobile

phone and mobile phone at the hospital’s end. The

corresponding modules of the actual system and its simulating

environment are:

B. Working

The Hardware continuously keeps on monitoring the ECG

and compares it with existing ECG plots and if the ECG

parameters are not in the range of the specified ECG plots, the

hardware sends MMS of the ECG to the mobile phone of the

patient; and finally this mobile phone will send that MMS

image of the ECG to the mobile phone at the hospital. The

paper shows working of this system in the form of simulation

using MATLAB and J2ME WTK.

TABLE I

SYSTEM MODULE AND ITS’S CORRESPONDING SIMULATION

Module of the System Proposed Simulation Environment of that Module in the System

Hardware MATLAB

Mobile Phone of Patient J2ME WTK Emulator 1

Mobile Phone at Hospital J2ME WTK Emulator 2

III. SOFTWARES USED FOR SIMULATION

A. MATLAB

MATLAB [2013b] – a fourth generation programming

language is used for simulating the hardware, creating and

manipulating the ECG signal; comparing ECG signal with

threshold ECG plots.

B. Java 2 Micro Edition Wireless Toolkit (J2ME WTK)

J2ME WTK– version 2.5.2 is used for simulating the

mobile phones.

http://www.ijettjournal.org/



Fig. 1 Block Diagram of System Proposed

C. Simulation Approach

The generation of ECG waveform is done using

MATLAB.

The MATLAB code continuously displays the current

ECG plot of the patient. This plot can be modified using

the Graphical User Interfaces (GUI) interface provided.

The creation of GUI”s has been done using GUIDE

(Graphical User Interface Development Environment),

the MATLAB graphical user interface development

environment [4].

Various options have been provided to manipulate the

ECG signal.

These options control the variable values for ECG

parameters, viz. amplitude of P-wave, length of PR

segment, distortion of QRS – complex, etc.

If these options are used, the necessary variables

associated with them are changed. This causes the ECG

plot to refresh under the current conditions.

Thus, after a certain threshold value of parameters is

breached, a Portable Network Group (PNG) image file

is generated.

This file is accessed by J2ME program code for sending

MMS from one emulator to other [5].

IV. RESULTS

Figure 2 shows the generation of ECG signals by the

MATLAB, as it appears on the GUIDE.

Fig. 2 ECG signal under monitoring

The GUI interface provided for manipulating the ECG

signal is as shown in Figure 3; this figure illustrates the

various buttons that can be used to simulate any required

changes in the ECG parameters. Fundamentally, only four

parameters are present. These have been chosen on the basis

of some identified illnesses [6].

The P-wave in the ECG can help determine Atrial

Premature Beat (APB). This can be made out due to

its shapeless appearance or even due changes in

amplitude.

The PR segment precedes the QRS complex, however,

if it is prolonged over 0.2 seconds, the first degree

atrioventricular block can be diagnosed.

The QRS complex helps determine myocardial

infarction (heart attack). The Q and S parameters in the ECG

vary, causing the QRS complex to be distorted. Thus we can

make out that a myocardial infraction has occurred [7].




Fig. 3 GUI Interface in MATLAB with Buttons for change in ECG Parameters

Figure 4 shows Emulator 1 sending emulator (resembling

the patient’s mobile device) and Emulator 2 receiving

emulator (resembling the mobile device at hospital).

Fig 4 J2ME WTK Emulators for sending and receiving ECG images

Fig. 5 GUI Interface in MATLAB with change in PR-segment duration

Figure 5 shows the MATLAB interface with a slight

change in the duration of PR-segment

Similar changes can be observed for parameters- P-wave

and QRS complex. After each change in a parameter, the

respective callback function in MATLAB has been

programmed to check the variation level. If this goes beyond a

safe threshold, an image file is generated in the resource

folder of the J2ME application for sending it as a Multimedia

Message. This image file is of the PNG format and is only

2KB in size. This file is accessed by the J2ME program code

for MMS. In J2ME, this file acts as the resource for sending a

Multimedia Message. This sending of Multimedia Message

has been facilitated by means of the SUN JAVA Wireless

Toolkit 2.5.2. The Wireless Toolkit provides development

environment for J2ME applications and also serves as a

testing tool by means of emulating the mobile screen.

Essentially two files are created in the text editor, which

are saved in the Java format. The MIDlet file - MMSMIDlet

uses a non-blocking, event-driven notification mechanism to

receive messages. It opens a server mode connection that can

receive incoming messages. However this server mode

connection can also be used to send messages. The class file -

MMSSender is used by the MMSMIDlet file to send multipart

messages. Since this file contains a connection created in the

client mode, it can only send messages. Both these files act as

source codes for the mobile device application, and when the

application is run on WTK simulator, these codes enable the

sending and reception of image.




Fig. 6 Receiving Emulator showing change in PR-segment duration

After a change in the values of the PR-segment duration

and P-wave amplitude, modified ECG images are received on

the emulators of J2ME WTK, figure 6 and figure 7,

respectively.

Fig. 7 Receiving Emulator showing an increase in the P-wave amplitude




Fig. 8 Receiving Emulator showing a negative P-wave and a distorted QRS complex

V. CONCLUSION

Advances in the field of Information and Communication

Technology has made it possible for the construction of small

sized wearable devices which are able to work in a wireless

environment, on their own, without the involvement of the

patient. The simulation results obtained were carried out to

show the working of the proposed system and thus it is now

practically possible to implement such a system for uses in

real time environments. The implementation of the system

proposed is simple and feasible, and can serve a host of

patients suffering from heart related diseases.

REFERENCES

[1] Subhasis Chaudhuri, Tanmay D. Pawar and Siddhartha Duttagupta, “Review of ECG Analysis,” in Ambulation analysis in Wearable ECG, Springer, 2009, pp. 15-21.

[2] Borromeo S, Rodriguez-Sanchez C, Machado F, Hernandez-Tamames JA and de la Prieta R, “A Reconfigurable, Wearable, Wireless ECG System,” presented at IEEE Int. Conf. EMBS, Lyon, France, 23rd-26th Aug. 2007.

[3] Madhur Gabahne and Zahir Aalam, “Design and Modeling of wearable ECG (Electrocardiogram) monitoring device for Heart Patients,” unpublished.

[4] Brian R. Hunt, Ronald L. Lipsman and Jonathan Rosenberg, A guide to MATLAB: for beginners and experienced user, 2nd ed. Cambridge University Press, 2006.

[5] James Keogh, J2ME: The Complete Reference, Berkeley, California, McGraw-Hill/Osborne, 2003.

[6] Dr. Aswini Kumar (2014, Nov. 14), ECG in 100 steps [Online]. Available: http://www.lifehugger.com/doc/120/ecg-100-steps

[7] P. E. Trahanias. “An Approach to QRS Complex Detection using Mathematical Morphology,” IEEE Trans. on Biomed. Eng., vol. 40, no. 2, pp. 201-205, Feb. 1993.


march 2015 simulation of wearable ecg monitoring device...

Documents