Electrocardiogram (ECG) Monitoring System using Bluetooth technology

Transcription

1 Electrocardiogram (ECG) Monitoring System using Bluetooth technology Zarina Md Amin, Suryani Ilias, Zunuwanas Mohamad Department of Electrical Engineering, Polytechnic of Sultan Abdul Salahuddin Abdul Aziz Shah, Shah Alam Selangor, Malaysia. Electrocardiogram (ECG) is a diagnostic tool used periodically to evaluate the electrical function and heart muscle. This tool is very easy to operate but requires a lot of training, especially when making sketches of ECG assessment. ECG can measure heart rate and rhythm, using electrodes placed on the skin. It can show blood flow to the heart muscle. A uniform system has been developed for routine placement of electrodes for ECG electrodes where the ten needed to produce 12 views of the heart's electrical [1, 2]. In contrast, heart rate monitoring requires only three electrodes which are placed on the right arm, left arm and left chest. This monitoring can only measure heart rate and rhythm, but not a complete ECG monitoring. Data extracted from the ECG can be used to find a variety of heart diseases such as breathing difficulty, chest pain, fainting and palpitations or feel the pulse of an abnormal chest. Figure 1 shows how the connection leads are connected to the patient's ECG and Figure 2 displays the ECG graph Figure 1: Figure 2: Showing a patient connected to the 10 lead ECG trace with Grid 1

2 (Source: en.wikipedia.org) (Source: cvphysiology.com) Recent efforts have been made to increase the capacity to produce data of patients more quickly and easily. Rather, the technology leader in medical engineering also looks deeper into how technology can help the hospital make monitoring more effectively and quickly without frequently visiting patients. In 2003, just two years after the Bluetooth wireless technology was used officially in the world. U.S. Food and Drug Administration (FDA) approved the first Bluetooth used in medical devices. It is the Serial Port Adapter for emergency room equipment, designed for applications such as wireless printing electrocardiogram or send medical images in the air [3]. Most recent example is the Bluetooth technology used in blood glucose meters which has been able to capture data using a PDA or laptop. This paper introduces a mobile system in which the heart's electrical activity is transmitted to the mobile via Bluetooth and released, processed, stored and visualized in real time. Long-term healthcare services for the elderly people are in the centre of attraction in all developed countries presently. Since the chronic diseases are very common among elderly people, it is necessary to monitor their physiological parameters constantly especially for those who live alone at home [5]. In addition to this, the main causes of sudden death in elderly people are heart malfunctions if they are not discovered in time. So, the electrocardiogram (ECG) signal must be continuously monitored [6]. It is evident that the importance of monitoring the ECG as diagnostic needs of a patient. The cardiovascular crisis is glaringly evident in developing countries. Both the urban and rural areas are experiencing a mounting epidemic of cardiovascular (CV) disease, which was until recently considered a disease of the 'urban rich' [7]. With changing technologies, communication technologies and telemedicine, in which data is transmitted in several ways indirectly from visiting doctors, have been increasingly used. Mobile telemedicine system becomes more important at all times, especially in remote patient care or in travels, away from the reference hospital treatment [8,9]. Many ECG studies - Bluetooth has identified prototype wireless ECG monitoring system and is able to read the ECG signal from the patient, send a signal via a Bluetooth link, and displays the ECG waveform 2

3 personal computer (PC) [10]. This type of system is desirable because it can operate without depending on the line of sight in the obstacles in between. Bluetooth enabled ECG monitoring system consists of three parts, the ECG sensors, signal processing circuit also PC and display interface. Bluetooth-enabled ECG Monitoring System Circuits, have ECG sensor built to detect, amplify and filter out the weak electrical signals obtained from the patient's body. Generally ECG analog signals from the sensors are converted into a binary bit sequence by using the analog-to-digital converter. Digital bits are stored in the microcontroller cushion before shipment. Signal processing circuit, act as intermediate nodes between ECG sensor circuit and a PC. The ECG data is sent to the display device via a Bluetooth link. ECG INSTRUMENTATION BLOCK LOW PASS FILTER MICROCONTROLLER FINAL STAGE BUFFER & ISOLATION BARRIER MODULE BLUETOOTH MODULE PC (LECTURER MONITORING CNTER) Figure 3: Block Diagram 3 electrodes are used to detect the ECG signal. Signal obtained represent an Einthoven bipolar lead. By convention, potential difference between right arm (RA) and left arm (LA) are measured, where positive electrode attached on the LA and on RA the negative electrode stick. Meanwhile electrodes on right leg (RA) function as reference electrode for recording. In principle the potential difference between LA and RA are within 1-3mV and ECG changes in 3

4 signal frequency from 0.02 to 150 Hz. This low value of the ECG from the sensors (electrodes) requires amplification by an amplifier with a gain of 1000 in the ECG instrumentation block. A low pass filter is used in this system in order to reduce the continuous noise produce by the component. Final stage buffer and Isolation Barrier Module are applied to protect the circuit. Several wireless technologies such as ZigBee, Bluetooth, GSM / GPRS and WLAN or others can be used to transmit the ECG signal. [11 ] In this study, we chose Bluetooth technology based on the fact that Bluetooth is a secure short-range technology that enables besides having a universal accepted standards, which are described in [12]. In particular, Bluetooth standard offer advantages of low EM interference, low cost, reduce power use and confidential data [11]. Furthermore Bluetooth is also available in most wearable devices such as laptop and mobile phones. Bluetooth module is assigned as a slave and PC (lecturer center) are function as a master. The ECG signal is sent continuously to the Bluetooth by using an acquisition unit. A PIC 16F877 microcontroller is used to convert analog signal to digital signal where it will be programmed to perform the following functions: capture and digitize the ECG signal, establish the connection to a PC using a Bluetooth and send data. Lecturer Monitoring Centre monitors student s results of the ECG experiments by receiving and visualizing the data from students group while doing their experiment. Through the user interface, a real time ECG signal can be viewed by the user. The system functions as follows: Communication via Bluetooth with acquisition board ECG visualization ECG storage View the events as it is occurred Hardware structure 4 ECG PIC BLUETOOTH MONITORING SYSTEM

5 Figure 4: Overall System Figure 4 shows the overall hardware used in this project. It consists of ECG board, PIC microcontroller, Bluetooth module and data monitoring system (computer). Data of the ECG is obtained when the microprocessor system is connected to the ECG and transferred to a PC using a Bluetooth connection. ECG circuit has a sensor that controls the PIC microcontroller (ADC and UART) for communication with a Bluetooth module. PIC microcontroller will convert analogue signals digitally at a sample rate based on the resolution of the ECG signal. Then the data from the ECG will be extracted and connected using Bluetooth, which functions as a data acquisition system (DAQ). Change in real time ECG signal on a computer sampled at 250Hz (sampling frequency). Data from the Bluetooth module will send to the USB dongle has been installed on the computer. Communication between Bluetooth module and USB dongle connected to using the assembly langauge and Bluetooth protocol in which digital signals can be processed through layers of wireless networking application. Finally, Visual Basic program displays the signal from the connection device. It is expected that the method will reduce the problem of monitoring systems in teaching and learning. ECG background and the implications for one s health will be explained. Implementation and theory for the ECG electrodes and ECG instrumentation will be provided in the theory. The transmission and data acquisition of the ECG signal via the microprocessor will be described. Interaction between ECG system and Bluetooth with sensor codes is presented. 5

6 Prototypes are reduced the configuration and cable. Bluetooth technology will communicate with the monitoring center and the data can be stored in computer thus pen and paper method can now be reduced in medical laboratory and also hospital environments. Data stored in file format, reducing the space, to improve, and to limit human error. Most importantly, less wire would mean less dangerous and less administrative implemented and also it is easy for the lecturer to monitor the student s data while doing their experiment. In hospital environment, changing the doctor a person would not be a problem, since the data can be saved in the computer and sent it from the previous doctor to the new ones. References [1] [2] [3] Len OTT, The Evolution of Bluetooth in Wireless Medical Devices, July [4] [5] M. B. khodabakhshi, and A. Janqorbani, "Screening and ECG signal using a mobile phone, along with the diagnosis", Thesis, Shahed University, [6] Chan, Brady, Harrigan, ornato, and rosen, ECG in Emergency Medicine and Acute Care, 2005, PP [7] Pamnani Divya, Express Pharma-Fortnightly, insight for pharma professionals, Jan , [8] A. khorovets, "What is an Electrocardiogram?" The internet journal of Health, Vol. 1 Number 2, [9] D. G. Clifford, A. Francisci, and P. E. McSharry, Advanced Methods and Tools for ECG Data Analysis, 2006, pp

7 [10] T. K. Kho, Rosli Besar, Y. S. Tan, K. H. Tee, K. C. Ong, Bluetooth-enabled ECG Monitoring System, Tencon 2005 IEEE Region 10, 2005, pp.1-5. [11] D. Kammer, G. McNutt, and B. Senese, Bluetooth Application Developer's Guide, Syngress Publishing, Rockland, Mass, USA, 2002 [12] Jordan,R.;Abdallah and C.T., Wireless Communication And Networking An Overview. IEEE Antennas and Propagation Magazine, vol 44 Issue:1, pp , Feb [13] R. Bouhenguel, I. Mahgoub, and M. Ilyas, Bluetooth security in wearable computing applications, in Proceedings of the International Symposium on High Capacity Optical Networks and Enabling Technologies, pp , November 2008 [14] The official Bluetooth wireless info site, last accessed:[1/7/2012] [15] Microcontroller data sheet at last accessed :[28/6/2012] 7