Design of remote real-time monitoring system for high-risk heart patients

1 Introduction

Cardiovascular diseases are often very critical, with severe symptoms and rapid changes. Once an attack occurs, it may cause great pain to the patient and even lead to syncope or sudden death. In particular, coronary heart disease, cardiomyopathy, a history of arrhythmia, a family history of sudden cardiac death, heart transplant history and other conditions are characterized by sudden onset, randomness and high sudden death rates. Death may usually occur within 1 hour after the onset of acute symptoms. Malignant ventricular fibrillation may even cause sudden death within 12 minutes. Patients with the above serious heart diseases are high-risk heart patients [1]. Therefore, how to make early diagnosis of high-risk heart patients, especially the vast majority of out-of-hospital patients, before the onset of the disease, and to guide rescue personnel to rush to the scene for rescue as soon as possible when the disease occurs, is the key to reducing the incidence of death among high-risk heart patients out-of-hospital due to lack of timely rescue. Electrocardiogram is a common and effective means of diagnosing heart disease. High-risk heart disease patients have a variety of high-risk electrocardiogram manifestations when they faint or die suddenly [2]. The continuous dynamic monitoring and analysis of electrocardiograms can help to detect and diagnose such diseases in an early stage.

Remote electrocardiogram monitoring plays a very important role in the prevention and treatment of heart disease. It has attracted great attention from scholars at home and abroad. PSTN-based remote electrocardiogram monitoring systems, in-hospital telemetry electrocardiogram monitoring systems, and the latest remote mobile monitoring systems based on embedded mobile computing devices have been successfully developed [3,4], meeting the basic requirements for continuous dynamic remote electrocardiogram monitoring of heart patients. However, in actual clinical promotion, the existing remote electrocardiogram monitoring systems or remote mobile electrocardiogram monitoring systems, especially for the monitoring of high-risk heart patients outside the hospital, still have shortcomings such as limited patient range of activity, lack of simultaneous multi-person monitoring function, and lack of patient geographic positioning function.

In view of the special background of medical monitoring and clinical rescue requirements of high-risk heart patients, this paper has developed a functional prototype based on GSM/GPRS wireless mobile communication system and GPS global satellite positioning system to achieve real-time monitoring, analysis and early diagnosis of ECG signals of high-risk heart patients outside the hospital, to prevent sudden death of patients to the greatest extent, and enhance patients' sense of security and comfort of life.

2 Working principle

The remote real-time monitoring system for high-risk heart patients given in this paper consists of two parts: a remote mobile terminal and a hospital monitoring center. A hospital monitoring center can monitor multiple patients at the same time. The remote mobile terminal is carried by the patient to monitor the patient's ECG signals anytime and anywhere, and transmit the ECG data to the hospital monitoring center in real time through the GSM/GPRS wireless mobile network so that doctors can make timely diagnosis. When the patient's ECG is abnormal, the hospital monitoring center will automatically alarm and prompt the doctor on duty; at the same time, the GIS system of the monitoring center automatically indicates the patient's current geographical location based on the GPS information uploaded by the mobile terminal. For patients with high-risk ECG manifestations and symptoms of illness, the doctor on duty will make an early diagnosis and issue a call for help; rescuers will quickly arrive at the scene to provide assistance based on the patient's geographical location provided by the command, to prevent the patient from sudden death to the greatest extent possible.
The main function of the embedded mobile terminal of this system is to collect the patient's three-lead ECG signal in real time. On the one hand, after simple analysis, some basic information is displayed on the mobile terminal to provide a local early warning function; on the other hand, the compressed ECG information and GPS longitude and latitude information of the patient are uploaded to the database of the hospital's central monitoring system through the GPRS communication network in batches.

The hospital monitoring center is the center of the entire remote real-time monitoring system. Its main function is to realize remote centralized monitoring, storage, analysis and early diagnosis of ECG signals of remote mobile monitoring terminal users, as well as playback and printing functions, and remote monitoring of the parameters and status of each terminal; combined with the powerful spatial location analysis function of the GIS platform, it can track, locate and display the geographical location of mobile users.

3 System Development

3.1 Embedded Mobile Terminal Design

(1) Hardware Design of Embedded Mobile Terminal The

hardware design of the embedded mobile terminal is based on the Philips LPC2200 32-bit microprocessor with ARM 7 architecture, with the EasyARM2200 processor module of Guangzhou Zhiyuan Electronics Company as the core, and some peripheral modules are expanded to realize the patient ECG data acquisition module, human-machine interface module, GPS module and GPRS module for communication with the hospital monitoring center. The system interface resources are fully utilized. Figure 1 is the hardware system architecture diagram of the entire design.

(2) Software design of embedded mobile terminals

The software design of embedded mobile terminals adopts the currently popular embedded system development technology. First, the real-time operating system uCOS-II is transplanted to the Philips LPC2200 embedded microprocessor, and the functions to be completed by the terminal are refined into several core tasks, which are uniformly scheduled by the uCOS-II real-time kernel. On a macro level, multi-task parallel execution is achieved, and the reliability and real-time performance of the system are greatly improved.

The preemptive operating system schedules tasks according to the priority level. According to the functions to be achieved by the system, the entire software system is divided into the following order of priority from high to low: ECG acquisition task, GPRS communication task, data analysis and LCD display task, GPS task. When the system is running, the system is first initialized, all data structures are initialized, stack space is allocated, and then a message queue for inter-task communication is established, and tasks are established and assigned priority. All new tasks are set to the ready state, and the system program starts to execute from the task with the highest priority.

3.2 Design of hospital monitoring center

The monitoring center system is built based on Windows NT LAN, mainly including GPRS network server, database server, ECG center monitoring workstation and GIS positioning management workstation.

This paper applies the C/S architecture design idea and adopts multi-tasking mode to ensure simultaneous monitoring of multiple remote users. The functional prototype of the entire ECG center monitoring system and GIS positioning management system is developed using Microsoft Visual C++6.0 tools, and the background database uses Microsoft SQL SERVER 2000 relational database system.

3.3 System prototype

Finally, the prototype of the remote real-time monitoring system for high-risk heart patients developed includes the remote embedded mobile terminal prototype shown in Figure 2 and the hospital monitoring center display interface shown in Figure 3. Using this prototype, the 3-lead ECG signal of a subject (located in Shanghai Zhabei Park) is collected in real time. The GPS module receives the latitude and longitude information of the Zhabei Park where the subject is located. After the signal analysis and processing of the terminal, it is transmitted to the laboratory monitoring center (with a real IP address) at the remote end (Fudan University) by the GPRS network for dynamic analysis and display. The monitoring center displays the results as shown in Figure 4. The normal heart rate of the subject is 87 beats/minute. The longitude and latitude are E 121.4525 and N 31.25793 respectively. The GIS map indicates that it is near Shanghai Zhabei Park.

4 Conclusion

Aiming at the special background of high-risk heart disease patients in medical monitoring and clinical rescue needs, this paper develops a system prototype for remote real-time monitoring of high-risk heart patients. The system is based on the GSM/GPRS wireless mobile communication system and the GPS global satellite positioning system, including an embedded mobile unit based on the ARM 7 processor and uCos-II microsystem and a hospital monitoring center software system developed by VC++. The preliminary experimental test on a subject shows that the prototype system can monitor the patient's dynamic electrocardiogram in real time and accurately locate the patient's geographical location.

At present, the research work of this system is only in the initial stage. Whether in theoretical research or specific design and implementation, there is still a lot of work to be done before the final clinical application goal. It can be foreseen that the final successful implementation of this system will make up for some shortcomings of existing remote mobile monitoring systems at home and abroad in actual clinical applications, and better solve the real-time dynamic monitoring of high-risk heart patients outside the hospital under the conditions of daily work, study, and life activities.