• 융합신호처리학회논문지
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• 제16권1호
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• pp.29-34
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• 2015

The ECG(Electrocardiograph) ambulatory test as called Holter is performed usually to diagnose several heart diseases causing different arrhythmias. This paper exposes the insights of the design of a 10-lead ambulatory ECG recorder. Reducing the size and minimizing the power consumption of the ECG recorder are crucial to allow long recording time without causing discomfort to the patient. This paper proposes lower hardware design and differential compression algorithm to extend the maximum 72 hours recording time in consideration of smaller and light-weighted recorder size. The performance results by newly introduced compression algorithm are shown and discussed.

• 대한한방내과학회지
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• 제30권2호
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• pp.422-430
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• 2009

Background : Stroke is the second leading cause of death in Korea, following cancer. Stroke consists of ischemic and hemorrhagic stroke, and ischemic stroke can be largely classified as atherothrombotic stroke or embolic stroke. Carotid intima-media thickness (IMT) is an indicator of atherosclerosis used commonly as a screening test for abnormalities of the coronary artery. 24-hour ambulatory ECG is widely used to screen for underlying diseases that causes syncope, palpitation, arrhythmia, etc. Objectives : Since both carotid IMT and 24-hour ambulatory ECG are used to screen for cardiac problems, we endeavored to explore the correlation between carotid IMT and 24-hour ambulatory ECG of stroke patients. Methods : The records of ischemic stroke patients who were admitted to Kyunghee Medical Center Oriental Hospital ward from March 2006 to May 2009 were reviewed. 28 patients who had both carotid Doppler US and 24-hour ambulatory ECG test undertaken during their admission were analyzed. The relationship of abnormal ambulatory results and common carotid artery(CCA) IMT were statistically analyzed using Fisher's exact test and t-test. Results : The mean age of the abnormal ambulatory group was older than the normal group (74${\pm}$ 8.0 vs. 61${\pm}$12.1, p=0.0098). Although insignificant, the abnormal ambulatory group showed much thicker CCA-IMT than normal ambulatory group (2.l7${\pm}$ 1.16 vs. 1.51${\pm}$0.97. p=0.l389). Conclusion: No significant correlation was observed between abnormal ambulatory results and CCA-IMT. However, the difference in CCA-IMT between the two groups was too big to be ignored and further investigation with larger and better controlled trials are warranted.

• 전기학회논문지
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• 제57권3호
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• pp.507-513
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• 2008

In this study, we develope an ambulatory ECG acquisition system by implementing a patch-style and wireless electrode. To alleviate the inherent noisy characteristics of the mobile signal, we apply a matched filter and concurrently detect R-peak values. Moreover, the measure for resolving shape distance is computed to estimate the relative similarity between two ECG signals and to decide whether the abnormal characteristics in ECG exist or not.

• 대한의용생체공학회:의공학회지
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• 제20권1호
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• pp.75-80
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• 1999

홀터 심전계는 일반 심전계와 달리 활동중의 심전도를 기록하므로서 복잡한 심장질환을 효과적으로 모니터링할 수 있으나 24시간 동안의 심전도를 수집하여 진단하기 때문에 급작스런 심장질환에 대해서는 대처할 수 없다. 따라서 본 논문에서는 홀터 심전계와 같은 이동형 심전도 단말기에 900Mhz 대역을 사용하는 부선 데이터 통신망 인터페이스를 첨가하여 심장 이상으로 인한 급사위험이 있는 환자를 감시${\cdot}$관리할 수 있는 보행형 감시 시스템 모델을 제안하고 이동형 심전도 단말기와 담당 의사를 위한 휴대형 단말기를 구현함으로써 무선 데이터 통신망을 이용한 보행형 감시 시스템이 구현될 수 있음을 검증하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 학술회의 논문집 정보 및 제어부문 B
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• pp.920-923
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• 2003

An wearable electrocardiogram (ECG) monitoring system is a widely used non-invasive diagnostic tool for ambulatory patient who may be at risk from latent life-threatening cardiac abnormalities. In this paper, we have a portable ECG monitoring system with conductive fiber which was characterized by the small-size and the low power consumption. The system consists of conductive fibers, one-chip microcontroller, ECG preprocessing circuit, and monitoring software to be able to record and analyze in PC. ECG preprocessing circuit is made of pre-amplifier with gain of 10, band-pass filter with bandwidth of 0.5-120Hz and 2.5V offset circuit for A/D conversion. ECG signals obtained by sensor are included with corrupted noises such as a baseline wandering, 60 Hz power noise and interference noise by body movement. For cancellation corrupted noises in signals obtained by conductive fiber, we used the wavelet decomposition of wavelet transforms in MATLAB toolbox.

• 전기학회논문지
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• 제61권6호
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• pp.865-871
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• 2012

In this study, ambulatory electrocardiogram(ECG) signal and the rhythms of heart beats are visualized in terms of R-R intervals and Heart Rate Variability(HRV) in the environment of an android plaform. With this aim, Graphical User Interface(GUI) is implemented by executing multi-thread Java programming modules including ECG, heart-beats, tachogram and visualization unit. ECG signals are acquired in an android device by receiving the data from ambulatory ECG sensory system. Finite Impulse Response(FIR) filters are implemented to eliminate the baseline wandering noises contained in the ambulatory signals and DC-offset level in R-R interval data. With simulating the normal or stress emotional state of a subject, we can find the fact that HRV can be successfully estimated and visualized in an android smart phone platform.

• 대한의용생체공학회:의공학회지
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• 제12권4호
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• pp.277-284
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• 1991

This study describes the ambulatory ECG monitoring system for the remote autom atic diagnosis. System: tlardware is based on one chip microcomputer(80c31) and its peripherals which consists of A/D, EPROM, RAM, LCD display and two preamplifiers, Power circuits, control logic circuits. A/D converted data were differentiated and low pass filtered. The detection of QRS complex and R point were accomplished by software algorithm based on adaptive threshold computed on low pass fi:leered signal. Rhythm analysis is performed by RR interval and average RR interval. The performance of QRS detection algorithm is evaluated by using MIT/BIH data base. Using this system, the trends of the arrythmia during the long term could be saved and displayed.

• 대한의용생체공학회:의공학회지
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• 제18권1호
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• pp.45-50
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• 1997

In this paper, we designed a Molter analysis system using the visual programming method It differs from the existing analysis system in that the various signal processing algorithms represented by icons were designed by GUI concept which provide unskilled user with easy and convenient analysis environment. In order to analyze ECG signal. we only select the icon representing an algorithm to be applied by mouse and arrange the selected icons upon the order to be jlrocessed on screen. As a result it provides a convenient usage and flexibility of analysis. Also, we can find the optimal algorithm for the ambulatory ECG analysis by comparing the several results obtained from the various analysis configuration.

• 대한의용생체공학회:의공학회지
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• 제11권1호
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• pp.13-18
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• 1990

Frequency responses of ambulatory electrocardiogram systems were measured. Phase shift was assessed by our improved Wagner's method. The characteristics of the systems were found much worse than that of ordinary ECG equipment both in gain and phase responses. The decay of -3dB in amplitude observed in 0.2Hz and the lead of 45 dog in phase was observed in 0.6Hz. In order to investigate which of these 2 responses play major role in generating false S -T deviation, mathe- matical filters were Composed in a computer and actual ECGs were fed. The false S-T deviation were found to be caused mostly by enormous lead in phase, and then, the compensation circuit to diminish the lead in phase was inserted in the commercial systemes. The compensated systems showed no false deviation in S-T segment.

• 제어로봇시스템학회논문지
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• 제15권4호
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• pp.406-412
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• 2009

ECG is used on purpose to keep good health or monitor cardiac function of aged person as well as on purpose to diagnose the disease of heart patients. The ambulatory ECG monitoring system under guarantee of safety and accuracy is very efficient to prevent the progress of heart disease and sudden death. These systems can detect the temporary change of ECG that is very significant to diagnose heart disease such as myocardial ischemia, arrhyamia and cardiac infarction. In this paper, we describe the ECG signal analysis algorithm and measurement device for ECG monitoring. The authors designed a small-size portable ECG device that consisted of instrumentation amplifier, micro-controller, filter and RF module. The device measures ECG with four electrodes on the body and detects QRS complex and ST level change in realtime. Also it transmits the measured signals to the personal computer. The developed software for ECG analysis in personal computer has the function to detect the feature points and ST level changes.