• 전기학회논문지
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• 제59권6호
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• pp.1143-1149
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• 2010

In this study, we propose a novel method to detect and enhance the feature of ST-segment which offers the crucial information for the diagnosis of myocardial infarction and ischemia. With this aim, PQRST features of Electrocardiogram initially are detected and subsequently ST-segment are estimated. And Dynamic Time Warping(DTW) transformation is applied recursively to minimize the difference in time between ST-segments and calculate the minimum cumulative distance that decides the degree of similarity among ST-segments. As of the results, the inherent characteristic of ST-segment can be emphasized in terms of time parameter and thus the diagnostic features of a ST-segment can be revealed further.

• 한국정보통신학회논문지
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• 제15권10호
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• pp.2223-2230
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• 2011

심전도는 심근허혈, 부정맥, 심근경색과 같은 심장질환의 진단에 이용된다. 특히 심근허혈은 ST 세그먼트의 형태 변화가 나타나는데, 이러한 변화는 일시적으로 나타나며 특별한 증상을 동반하지 않는다. 따라서 지속적인 모니터링을 통해서 ST의 일시적인 변화를 검출하는 것이 매우 중요하다. 이에 본 연구에서는 심근허혈 진단을 위한 ST세그먼트 형태 분류 알고리즘을 제안한다. 이는 전처리 과정과 적응가변형 문턱치를 통해 R파와 각 특징점을 검출 한 후 S와 T파사이의 굴곡점으로부터 특정한 기울기 정보를 추출하여 ST의 기울기 기준점과 비교함으로써, 검출된 ST를 6가지 형태로 분류하는 방법이다. 개발된 알고리즘은 심전도로부터 ST 레벨 변화 구간을 검출하고, 검출된 구간에 대해서도 ST의 형태를 분류함으로써 심전도 레벨 변화뿐만 아니라 형태에 대한 정보도 제공한다. 제안한 알고리즘의 심근허혈 패턴 진단 성능을 평가하기 위해서 European ST 데이터베이스를 사용하였다. 성능 평가 결과 가장 높은 분류성공률은 99.4%이며, 낮은 성공률은 68.48%를 나타내었다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.176-180
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• 2004

The ST-segment that the beginning part of T wave is the important diagnostic parameter to finding myocardial ischemia. Abnormal ST appears in two types. One is the level change, and the other is the pattern change. In this paper, we describe the monitoring of abnormal ST using PC based system. Hardware of this system consists of transmitter, receiver and PC. The function of transmitter is measuring ECG in three channels which are selected manually and transmitting the data to receiver by digital radio way. Connection with receiver and PC is by RS232C, and the data received on the PC is analyzed automatically by ECG analysis algorithm and saved to file. In the algorithm part for detecting abnormal ST, ST-segments are approximated by a polynomial. This method can detect all of the deviation and pattern change of ST-segment regardless the change in the heart rate or sampling rate. To gain algorithm reliability, the method rejects distorted polynomial approximation by calculation the difference between the approximated ST-segment and original ST-segment. In pre-signal processing, the wavelet transformation separates high frequency bands including QRS complex from the original ECG. Consequently, the process improves the performance of detecting each feature points.

• 대한핵의학회지
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• 제28권2호
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• pp.177-185
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• 1994

Pharmacologic coronary vasodilation in conjunction with myocardial perfusion scintigraphy has become an alternative to dynamic exercise test for the diagnosis and risk stratification of coronary artery disease, especially in patients who are unable to perform adequate exercise. Dipyridamole and adenosine have been used for pharmacologic stress testing with myocardial perfusion imaging. Adenosine is a potent coronary vasodilator with rapid onset of action, short half-life, near maximal coronary vasodilation and less serious side effects. ST segment depression has been reported in about 7-15% of patients with coronary artery disease receiving dipyridamole in conjunction with myocardial perfusion imaging. The exact cause and clinical significance are not known. In order to evaluate the relationship between adenosine-induced ST segment depression during $^{99m}Tc$-MIBI myocardial perfusion scintigraphy and the severity of coronary artery disease, we performed $^{99m}Tc$-MIBI imaging after intravenous Infusion of adenosine In 120 patients with suspected coronary artery disease. Of the 120 patients, 28 also performed coronary angiography. There were 24 patients with ST segment depression during $^{99m}Tc$-MIBI scintigraphy and 96 patients without ST segment depression. Adenosine was infused Intravenously at a dose of 0.14mg/kg per minute lot 6minutes and $^{99m}Tc$-MIBI was injected at 3 minute. We then com-pared the hemodynamic changes, side effects, scintigraphic and angiographic findings. Heart rate increased $90{\pm}19$ beats/minute in the group with ST depression compared with $80{\pm}16$ beats/minute in the group without ST depression(p<0.05). Baseline systolic blood pressure was significantly higher in the group with ST depression($152{\pm}27$ mmHg) than in the group without 57 depression($140{\pm}21$mmHg, p<0.05). Double product at baseline($10.90{\pm}2.77$ versus $9.55{\pm}2.34\;beats/minute{\times}mmHg$) and during adenosine infusion($12.72{\pm}3.89$ versus $10.83{\pm}2.98\;beats/minute{\times}mmHg$) were significantly higher in the group with ST depression(p<0.05). The incidence of anginal chest pain was also significantly higher in the group with ST depression(ST versus 29%, p<0.0001). The $^{99m}Tc$-MIBI images were abnormal in 23(96%) patients with ST segment depression and 66(69%) patients without ST segment depression(p<0.05). In patients with ST segment depression, there were more reversible perfusion defects than in patients without ST segment depression(83 versus 55%, p<0.05). The number of abnormal segments were significantly higher in the group with ST depression($3.05{\pm}2.01$ versus $1.51{\pm}1.45$, p<0.005). In patients with ST segment depression, there were more segments of reversible perfusion defects than in patients without segment depression($2.15{\pm}2.11$ versus $0.89{\pm}1.24$, p<0.05). There were no differences in the angiographic severity by vessel(p ; NS). We concluded that ST segment depression during $^{99m}Tc$-MIBI myocardial perfusion scintigraphy with Intravenous adenosine is related to the severity of coronary artery disease.

• 생명과학회지
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• 제19권1호
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• pp.81-86
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• 2009

12주 유산소 트레이닝 결과, 제 2형 당뇨 대상자의 신체적 특성 및 심혈관계 기능은 향상되었고, 심근허혈을 판단하는 ST-level과 ST-slope가 트레이닝 후 감소함을 나타냈다. 또한, 당뇨에서 자주 나타나는 대표적인 자율신경계 이상 마커인 QTc interval을 감소시켰다. 따라서, 12주 유산소 트레이닝은 심혈관계 기능과 당뇨로 인한 심장허혈, 자율신경계 기능을 증진시킨 것으로 나타냈다.

• 감성과학
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• 제10권2호
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• pp.147-154
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• 2007

심장의 활동을 기록한 심전도는 심장의 상태에 대한 가치 있는 임상 정보를 제공한다. 지금까지 심전도를 이용한 심장 질환 진단 알고리즘에 대한 많은 연구가 진행되어 왔으나, 심장 질환에 대한 국내 진단 결과의 부정확성 때문에 외국의 진단 알고리즘을 사용하고 있다. 이 논문에서는 원시 심전도 데이터로부터 심장 질환 진단의 파라미터인 ST-segment 추출 방법을 제안한다. ST-segment는 관상동맥 질환 예측에 활용되므로 데이터마이닝의 분류기법을 적용하여 질환을 예측한다. 또한 연관규칙 마이닝을 통해 환자들의 임상 데이터로부터 심장 질환자들의 임상적 특징을 예측한다.

• Journal of Korean Neurosurgical Society
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• 제42권3호
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• pp.184-190
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• 2007

Objective : The authors retrospectively analyzed clinical and radiographic features of patients who developed symptomatic adjacent segment degeneration (ASD) that required re-operation. Methods : From 1995 to 2004, among 412 patients who underwent posterior lumbar fusion surgery, the authors experienced twenty-six patients who presented symptomatic ASD. Records of these patients were reviewed to collect clinical data at the first and second operations. Results : The patients were 9 males and 17 females whose mean age was $63.5{\pm}8.7$ years. Among 319 one segment and 102 multi-segment fusions, 16 and 10 patients presented ASD, respectively. Seventeen ASDs were noticed at the cephalad to fusion (65%), eight at the caudad (31%), and one at the cephalad and caudad, simultaneously (4%). All patients underwent decompression surgery. Nine patients underwent additional fusion surgeries to adjacent degenerated segments. In 17 patients who underwent only decompression surgery without fusion, the success rate was 82.4%. In fusion cases. the success rate was observed as 55.5%. There were no statistically significant factors to be related to development of ASD. However, in cases of multi-level fusion surgery, there was a tendency toward increasing ASD. Conclusion : Multi-segment fusion surgery could be associated with a development of ASD. In surgical treatment of symptomatic ASD, selective decompression without fusion may need to be considered as a primary procedure, which could reduce the potential risk of later occurrence of the other adjacent segment disease.

• 한국응급구조학회지
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• 제25권1호
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• pp.243-249
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• 2021

A decrease in coronary blood flow leads to an imbalance between the supply of oxygen to the myocardium and its demand, and reversible or irreversible damage to the myocardium could occur depending on the severity of the resultant ischemia and the duration of the imbalance. This imbalance results in a cascade of ischemic reactions in the following order: metabolic abnormalities, diastolic dysfunction, systolic dysfunction, and electrocardiogram changes. Variant angina is caused by the closure of the coronary artery due to reversible coronary artery spasm, resulting in myocardial ischemia and subsequent chest pain as a clinical symptom. Variant angina may be observed as ST segment elevation in electrocardiogram measured when present in chest pain. However, 12-lead electrocardiogram performed after the patient's chest pain resolves does not help in the diagnosis. Since the duration of chest pain appears to be <15 minutes, it is important to perform the 12-lead electrocardiogram when clinical symptoms are present. If nitroglycerin is administered without performing 12-lead electrocardiogram by 119 pre-hospital paramedics, the chest pain would be resolved, making it impossible to identify changes in the ST segment. Before administration of nitroglycerin, changes in the ST segment must be recorded by performing 12-lead electrocardiogram.

• 대한의용생체공학회:의공학회지
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• 제28권5호
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• pp.665-675
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• 2007

The morphological change of ECG is the important diagnostic parameter to finding the malfunction of a heart. Generally ST segment deviation is concerned with myocardial abnormality. The aim of this study is to detect the change of ST in shape using a polynomial approximation method and the reference ST type. The developed algorithm consists of feature point detection, ST level detection and ST shape classification. The detection of QRS complex is accomplished using it's the morphological characteristics such as the steep slope and high amplitude. The developed algorithm detects the ST level change, and then classifies the ST shape type using the polynomial approximation. The algorithm finds the least squares curve for the data between S wave and T wave in ECG. This curve is used for the classification of the ST shapes. ST type is classified by comparing the slopes of the specified points between the reference ST set and the least square curve. Through the result from the developed algorithm, we can know when the ST level change occurs and what the ST shape type is.

• Journal of Preventive Medicine and Public Health
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• 제39권6호
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• pp.485-492
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• 2006

Objectives : To measure the distribution of electrocardiographic ST segment depression, and evaluate its relationships with cardiovascular risk factors based on the cross-sectional studies within a rural Korean community Methods : This study analyzed 1,343 persons, over 40 years old, who participated in a baseline survey during 2002-2005; the exclusion criteria included: a past history of myocardial infarction and angina pectoris, and specific conduction abnormalities. A Standard 12 leads ECG was recorded using an FCP-2101 (Fukuda Denshi Co.). The ST segment depression was retrospectively measured by a physician, according to the Minnesota code classification. Results : ST segment depression was found in 3.6 and 6.4% of male and female participants, respectively. After adjusting for age, gender, smoking, physical activity and obesity differences, high blood pressure showed significant relations with ST depression in females (male ORs=2.67, 95% CI=0.85-8.50; female ORs=2.62, 95% CI=1.29-5.32) Conclusions : As an ischemic ECG sign, ST depression was related to hypertension in female participants. This relationship remained significant, even after cases with left ventricular hypertrophy were removed.