• Progress in Superconductivity
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• 제9권1호
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• pp.35-39
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• 2007

Myocardial ischemia causes heterogeneity of ventricular repolarization and sometimes produces changes of the ST-T wave in ECG. Therefore, morphological changes of ST-T waveform in ECG have a clinical significance in diagnosing myocardial ischemia. In this study, we investigated the ST-T changes caused by myocardial ischemia in magnetocardiography (MCG). We analyzed MCG patterns of biphasic T, ST segment deviations from baseline, main current angle of $T_{peak}$ and $T_{peak}$ dispersion in 300 CAD patients without ST elevation in ECG, 122 symptomatic patients and 48 normal subjects. MCGs were recorded by multichannel SQUID system in a magnetically shielded room. As results, we found that appearances of the abnormality were strongly correlated with the severity of myocardial ischemia. Also we found that the percentage of the patients showing MCG changes were higher than those in ECG. These results show that morphological changes of ST-T waveform in MCG can be used as a marker of myocardial ischemia.

• Clinical and Experimental Pediatrics
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• 제58권7호
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• pp.263-266
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• 2015

Purpose: Ventricular repolarization is assessed using the QT interval corrected by the heart rate (QTc) via an electrocardiogram (ECG). Prolonged QTc is associated with an increased risk of arrhythmias and cardiac mortality. As there have been few reports regarding the effects of hyperthyroidism on ventricular repolarization, we studied the association between serum free thyroxine (free T4 [fT4]) and thyroid stimulating hormone (TSH) levels and the QTc interval. Methods: Thirty-eight patients with hyperthyroidism (<30 years old) were included, and we used their clinical records and available ECGs (between August 2003 and August 2011) to evaluate the association between their fT4 and TSH levels and their QTc interval. In addition, we studied the ECGs of 72 age-matched patients with no hyperthyroidism (control group) and compared their data with that from the patients group. Results: The QTc duration in patients with hyperthyroidism was significantly prolonged compared to that in the control subjects (P<0.001). In addition, the number of hyperthyroid patients with abnormal prolonged QTc was significantly higher than that in the control group (P<0.001). Among the patients with hyperthyroidism, patients with prolonged QTc and borderline QTc had higher fT4 levels and there was positive correlation between their fT4 levels and their QTc interval (P<0.05). However, no correlation was observed between their TSH levels and their QTc interval. Conclusion: We report that hyperthyroidism is associated with QTc prolongation. The correlation between the fT4 levels and the QTc interval suggests that thyroid status is associated with QTc values and the risk of cardiac mortality.

• Journal of Yeungnam Medical Science
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• 제31권2호
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• pp.94-98
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• 2014

Background: We analyzed the changes in QT dispersion (QTd) in children with Kawasaki disease (KD), and determined the presence of repolarization abnormality in these children even in the absence of coronary artery abnormalities. Methods: Ninety-one children with KD and 20 healthy controls were enrolled in this retrospective study. Serial echocardiographic and electrocardiographic (ECG) measurements in the beginning of treatment, 2nd month and 6th month after the diagnosis were compared. Fifty-one of 91 children had at least 2 serial ECG data. The number of patients who had 3 consecutive ECG data was 23. Results: Among the 67 KD patients with no coronary artery changes, the consecutive mean QTd values were 41.86 ms, 37.84 ms, and 25.47 ms, respectively (26 ms for controls). In the analysis of changes among KD patients without coronary artery abnormalities, QTd showed a significant decrease with time (p=0.01). Especially, the 1st month and the 6th month QTd values were significantly different (p=0.028). The mean QTd values in KD patients with coronary artery changes were significantly higher than those in KD patients with no coronary artery changes at each time (1st, 2nd, and 6th month exam). Conclusion: QTd is significantly increased in children during the early stage of KD. Repolarization abnormality may exist during the acute stage of KD, regardless of the echocardiographic changes.

• The Korean Journal of Pain
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• 제13권1호
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• pp.115-118
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• 2000

Stellate ganglion block is most commonly used in pain clinic because it is an easy procedure and it has broad indications reported that Angina pectoris, tachyarrhythmia and long QT syndrome (LQTS) are indicated. LQTS is a disorder of the abnormalities of cardiac sympathetic innervation and of myocardial repolarization. LQTS is characterized by marked prolongation of the QT interval, often manifestating as syncope, seizures, or sudden death due to polymorphic ventricular tachyarrhythmia known as torsades de pointes. Treatment of symptomatic patients usually begin with beta blocker. The elective treatment of LQTS patients unresponsive to beta blocker is the left cardiac sympathetic denervation. We report a case of LQTS patient who had received stellate ganglion block.

• The Korean Journal of Pain
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• 제31권1호
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• pp.3-9
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• 2018

Long QT syndrome is a cardiac repolarization disorder and is associated with an increased risk of torsades de pointes. The acquired form is most often attributable to administration of specific medications and/or electrolyte imbalance. This review provides insights into the risk for QT prolongation associated with drugs frequently used in the treatment of chronic pain. In the field of pain medicine all the major drug classes (i.e. NSAIDs, opioids, anticonvulsive and antidepressant drugs, cannabinoids, muscle relaxants) contain agents that increase the risk of QT prolongation. Other substances, not used in the treatment of pain, such as proton pump inhibitors, antiemetics, and diuretics are also associated with long QT syndrome. When the possible benefits of therapy outweigh the associated risks, slow dose titration and electrocardiography monitoring are recommended.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1994년도 추계학술대회
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• pp.61-64
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• 1994

This paper describes the construction of an anisotropic three dimensional ventricular model based on the bidomain model. The cardiac artivation process in the normal cardiac cell and the myocardiac ischemic cell are simulated by the Huygen's principle. The depolarization process in the myocardial ischemia displays the delayed activation compared to the normal state. The repolarization process is simulated by the myocardial potential at the arbitrary ellapsed time after activation process.

• 한국초전도학회:학술대회논문집
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• 한국초전도학회 2007년도 High Temperature Superconductivity Vol.XVII
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• pp.52-52
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• 2007

• 보험의학회지
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• 제29권2호
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• pp.22-28
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• 2010

Medical risk selection or mortality analysis is very important in insurance medicine. Among many kind of source articles there have been several limitations. There are few long-term follow-up studies in rare disease, as Romeo's article. We can do mortality analysis of this type using cause of death within the article and assumption of expected mortality q'. In the case of article which is published in foreign country such as Tikkanen et al, we can use comparative group from the control group within source article. It is another way for mortality analysis of limited article. However Retrospective study even performed in Korea, is unusable for estimation of extra-mortality.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.294-294
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• 2000

In this paper, we would like to discuss the signal processing and the algorithm for ECG analysis. The ECG gives us information about the condition of the heart muscle, because myocardial abnormality or infarction is inscribed on the ECG during myocardial depolarization and repolarization. Analyzing the ECG signal, we can find heart disease, for example, arrhythmia and myocardial infarction, etc. Particularly, detecting arrhythmia is more important, because serious arrhythmia can take away the life from patients within ten minutes. The wavelet transform decomposes the ECG signal into high and low frequency component using wavelet function. Recomposing high frequency bands including QRS complex, we can detect QRS complex and eliminate the noise from the original ECG signal. To recognize the ECG signal pattern, we adopted the curve-fitting partially and statistical method. The ECG signal is divided into small parts based on QRS complex, and then, each part is approximated to the polynomials. Comparing the approximated ECG pattern with some kinds of heart disease ECG pattern, we can detect and classify the kind of heart disease.

• 전기의세계
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• 제23권5호
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• pp.47-53
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• 1974

The electrical cardiac pacemaker model described in this paper simulates the most important functional properies of cardiac pacemaker cells. It is a minimum-parameter model which has a simple relaxation oscillator circuit as its main element. The electrical cardiac pacemaker model is analyzed in detail in order to show that its characteristic is similar to that of cardiac pacemaker cells. The main feature of the model is the possibility of controlling the time course phase 4 depolarization, the threshold level and the maximum level of repolarization, the rate of cardiac pacemaker. Emphasis is placed on phenomena of acceleration and frequency entrainment. This particular pacemaker model is very useful for the study of interactions between cardiac pacemakers and the description of the mechanism of arrhythmias.