• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.269-273
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• 1999

Combination of mental stress task with noise background is a traditional tool employed in psychophysiology. However, intensity of background noise is a factor affecting both performance on test and psychophysiological responses associated with stress evoked by mental load in noisy environment. In the current study on 7 subjects we analyzed the influence of white noise (WN) intensity (55, 70, and 85 dB[A] ) on psychophysiological responses during word recognition test performed on noise background. There were recorded following physiological variables: electrodermal activity (EDA) , namely, skin conductance level (SCL), skin conductance response (SCR) amplitude (SCR-A), rise time and total number of SCRs (N-SCR); cardiovascular activity, e.g., heart rate (HR), respiratory sinus arrhythmia (RSA) index, pulse transit time (PTT), finger pulse volume (PV), skin temperature (SKT) and respiratory activity, such as respiration rate (RESP-R) and inspiration wane amplitude (RESP-A) during baseline resting state and 40 s long performance on 3 similar Korean word recognition tests with different WN intensity (55, 70, and 85 dB). Electrodermal responses (SCR-A, SCL, N-SCR) demonstrated gradual increment with increased intensity of noise, and this increase of response magnitude with higher intensity of noise was typical also for r skin temperature (phasic SKT decrease) and pulse volume (phasic and tonic PV decrease). However, some cardiovascular and respiratory responses did not exhibit same tendency of gradual increase of reactivity , namely HR, as well as RESP-R and RESP-A showed decrement of response magnitudes. Important finding in terms of cardiovascular reactivity was that 55 and 70dB evoked similar profiles, while 85dB WN resulted in significantly different profile of reactions, suggesting that there exists a threshold level after which intensive auditory stimulation elicits psychophyslological responses pattern of different quality. There are discussed potential autonomic mechanism involved in mediation of observed physiological responses.

• Journal of The Korean Society of Clinical Toxicology
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• v.4 no.1
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• pp.78-81
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• 2006

Mad-honey poisoning is mainly brought about by the honey imported from Napal, Turkey, Brazil and other parts of Europe. This mad honey is extracted from Ericaceae plants of Rhododendron species and contains grayanotoxins that causes poisoning. These toxic compounds exert a specific stimulatory action on membrane permeability to Na+ions in various excitable tissues and cause depolarization of cell membranes. The toxic effects of grayanotoxins contained honey are mainly cardiovascular disturbances with bradycardia, cardiac arrhythmia, hypotension. There are Other symptoms like nausea, vomiting, salivation, dizziness, weakness and loss of consciousness. The precise amount for a toxic dose is not known. In general the severity of the honey poisoning depends on the amount ingested. Two cases of mad-honey poisoning are described here. Both patients showed bradycardia and arterial hypotension after ingestion of honey which was brought from Nepal. They were recovered fully within 24 hours after administration of fluids and atropine sulphate.

• Journal of Veterinary Clinics
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• v.32 no.1
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• pp.101-104
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• 2015

A 4-years-old, intact male Golden retriever dog was presented with abdominal distension and dyspnea. Physical examination revealed arrhythmia and cardiac murmur. Generalized cardiomegaly, pleural effusion and ascites were shown on thoracic and abdominal radiographs. Two-dimensional echocardiography revealed abnormal mitral and tricuspid valve motion, mitral and tricuspid regurgitation, left ventricular eccentric hypertrophy and left atrial dilation. Color-flow Doppler imaging revealed turbulent flow extending into the left ventricle during diastole from the mitral valve orifice, and into the left atrium during systole. Spectral Doppler recordings revealed highly increased early diastolic mitral valve inflow and prolonged pressure half-time of mitral inflow. Based on the echocardiographic examination, the diagnosis was made as the mitral valve dysplasia concurrent with mitral valve stenosis and tricuspid valve dysplasia.

• Journal of Chest Surgery
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• v.25 no.11
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• pp.1362-1368
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• 1992

Between March 1986 and November 1992, thirty-one patients with left main coronary artery stenosis[LMCAS, over 50% of cross sectional area] were revascularized at Seoul National University Hospital. The incidence of LMCAS was 20.8%[31/149]. The male:female ratio was 15:16. Age ranged from 39 to 70 years, with a mean age of 51 years. The anginal syndrome was composed of 23 unstable, 6 stable and 2 post-infarction angina preoperatively. There were sixteen isolated LMCAS, four ostial stenosis and eleven combined distal and /or right coronary artery stenosis. The degree of LMCAS was 50-74% in 21 patients[67.7%], 75-89% in one[3.6%] and 90-99% in 9[29.1%]. There was no case with 100% obstruction. Of the total patients with LMCAS, 11 patients received 4 distal anastomoses, another 11 patients had 3 distal anastomoses, and 8 patients needed 2 distal anastomoses. The overall operative mortality was 12.9%[4 /31], and the incidence of which was higher than the remaing group [6.8%, 8/118]. The causes of death were myocardial infarction[2 patients], ventricular arrhythmia[1 patient] and brain damage[1 patient]. All patients have been followed-up for average 28.9 months[1-76 months]. There was no late death. But one patients experinced anginal recurrence. In conclusion, making allowance for its notorious clinical results and relatively higher incidence in Korea, aggressive surgical techniques such as retrograce myocardial perfusion may be mandatory while we are in a learning phase.

• Journal of Chest Surgery
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• v.26 no.2
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• pp.141-147
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• 1993

A total of 40 patients having a diagnosis of atherosclerotic coronary arterial disease were analysed on the operative outcomes according to variables as follows: 1) preoperative risk factors such as age, sex, CCS (Canadian Cardiovascular Society) functional class, type of angina, number of diseased vessel, presence of left main coronary artery stenosis, previous history of habitual smoking and presence of other medical diseases (diabetes mellitus, essential hypertension), 2) preoperative management such as intravenous infusion of nitroglycerine, preoperative IABP (intra-aortic balloon pump) support and whether the operation was scheduled as emergency or not, 3) intraoperative variables such as infusion method and composition of cardioplegic solutions, number of distal anastomosis, use of internal mammary artery, total cardiopulmonary bypass time and total cross clamp time. Complications included operative death in 12.5％, perioperative myocardial infarction in 25.0％ and perioperative arrhythmia in 17.5％. Nineteen perioperative variables were analyzed to identify risk factors for these end points. For operative death, presence of left main coronary artery stenosis (p = 0.056) and cardiopulmonary bypass time (p = 0.029) were significant in the univariate analysis, but presence of left main coronary artery lesion (p = 0.011, $\chi$$^2$= 6.45) and abscence of preoperative of IABP support (p = 0.069, $\chi$$^2$ = 3.30) were independent predictor in multivariate analysis (stepwise linear logistic regression).

• Journal of Chest Surgery
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• v.26 no.2
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• pp.75-79
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• 1993

Myocardial protection against ischemic and reperfusion injuries is still in troublesome eventhough couples of the way of myocardial protection have been applied since 1970's. One of the possibility in myocardial protection is adding Fructose-l,6-diphosphate(FDP) in cardioplegic solution. It is assumed that FDP can promote ATP production under anaerobic condition as well as inhibiting the supressing effect of lactate on phosphofructokinase. We compared the myocardial protecting effects of FDP in crystalloid cardioplegic solution (St. Thomas formula, 10$^{\circ}C$, pH = 7.4) and reperfusate using isolated rat hearts in modified Langendorf apparatus by the parameters of preischemic and post reperfusing heart rate, time to first beat, occurance of arrhythmia, time to stabilization, and the rate of left ventricular pressure developing. Group A (n = 10), containing no FDP in cardioplegic and reperfusing solutions was control. Group B (n = 5), containing FDP in cardioplegic solution, showed statistically significant superiority of postischemic left ventricular pressure development than the control group. Group C (n = 5), containing FDP in reperfusate, showed statistically significant myocardial depressing effect than the controls. Other parameters were unremarkable. The cause is uncertain, but it is assumed that the negative feedback inhibition of FDP in energy metabolism or unknown blocking effect of FDP on certain transmembrane ionic currents is present. In conclusion, 1) FDP in cardioplegic solution has beneficial effect on postischemic left ventricular preservation. 2) FDP is strong acid when is hydrolyzed, so precise acid titration is neccessary. 3) FDP in reperfusate has negative left ventricular preservation, otherwise the mechanism is still uncertain.

• Journal of Chest Surgery
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• v.33 no.3
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• pp.207-211
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• 2000

Backgroud: Conventional cardiac transplantation with each atrial anastomosis designed by Shumway and associates has been used widely in cardiac transplantation because of its simplicity and efficiency. There have been many reports about the postoperative atrioventricular value regurgitation resulting from the alteration in atrial geometry after cardiac transplantation by Shumway's technique. New surgical technique of direct anastomosis of superior vena cava, inferior vena cava, right pulmonary vein and left pulmonary vein was introduced to overcome the those problems. We performed this study to test the feasibility of this new surgical technique prior to application to clinical practice. Material and Method: Conventional cardiac transplantation was performed on 12 mongrel dogs(Group I) and cardiac transplantation with new surgical mthod of direct anastomosis of SVC, IVC, left and right pulmonary veins was performed on 11 mongrel dogs(Group II). After weaning from cardiopulmonary bypass, we compared the postoperative rhythm, hemodynamic data, and echocardiographic findings between two groups. Result : The cardiopulmonary bypass time and graft ischemic time were 119.0$\pm$4.4 minutes, 162.0$\pm$4.5 minutes respectively in group I, and 140.0$\pm$7.1 minutes, 180.5$\pm$5.4 minutes respectively in group II. The cardiopulmonary time and graft ischemic time in group II were longer than those of group I (p<0.05). There were 3 cases of failure to weaning from cardipulmonary bypass onein group I and two in group II, and this difference was not significant statistically. Sinus rhythm was regained postoperatively in 58% (group I) and 82%(group II), without statistical significant between 2 groups. Postoperative echolcardiography showed 2 cases of tricuspid value regurgitation and 1 case of mitral regurgitation in group I, and no regurgitation of atrioventricular value in group II. Conclusion: Although these was no statistically significant difference between 2 groups, there was tendency of less arrhythmia and less atrioventricular valvular regurgitation in group II. We suggested that the new surgical technique could be a useful strategy in heart transplantation, especially in the case of size mismatching between donor and recipient.

• Journal of Chest Surgery
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• v.53 no.3
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• pp.127-131
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• 2020

Background: This study was conducted to evaluate the safety and efficacy of left atrial appendage (LAA) excision using a vascular stapler. Methods: Fifty consecutive patients (mean age, 68±9 years) who underwent LAA excision using a vascular stapler during concomitant cardiac surgery were enrolled. In all patients, the excision site was evaluated using computed tomography at a median of 7 days (interquartile range, 5-13.3 days) postoperatively. The safety endpoint of this study was the occurrence of LAA excision-related events, which were defined as bleeding from the excision site that required reinforcement sutures or reoperation due to excision site bleeding. The efficacy endpoint was LAA excision failure, which was defined as a remnant LAA (a stump >1 cm in maximum length) or extravasation of radiocontrast dye. Results: LAAs were excised using 60- and 45-mm vascular staplers in 49 patients and 1 patient, respectively. Reinforcement sutures were needed in 4 patients due to staple-line bleeding and in 4 patients due to bleeding of the surrounding tissues. No patient underwent reoperation due to staple-related bleeding. A remnant LAA was observed in 2 patients, while extravasation of radiocontrast dye was not observed in any patients. Conclusion: LAA excision using a vascular stapler may be an effective technique for LAA exclusion. Delicate handling of the stapler device and LA tissue is required to prevent procedure-related complications.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.4
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• pp.945-952
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• 2013

The R wave of QRS complex is the most prominent feature in ECG because of its specific shape; therefore it is taken as a reference in ECG feature extraction. But R wave detection suffers from the fact that frequency bands of the noise/other components such as P/T waves overlap with that of QRS complex. ECG signal processing must consider efficiency for hardware and software resources available in processing for miniaturization and low power. In other words, the design of algorithm that exactly detects QRS region using minimal computation by analyzing the person's physical condition and/or environment is needed. Therefore, efficient QRS detection based on SOM(Subtractive Operation Method) is presented in this paper. For this purpose, we detected R wave through the preprocessing method using morphological filter, empirical threshold, and subtractive signal. Also, we applied dynamic backward searching method for efficient detection. The performance of R wave detection is evaluated by using MIT-BIH arrhythmia database. The achieved scores indicate the average of 99.41% in R wave detection.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.3
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• pp.705-711
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• 2013

QRS detection of ECG is the most popular and easy way to detect cardiac-disease. But it is difficult to analyze the ECG signal because of various noise types. Also in the healthcare system that must continuously monitor people's situation, it is necessary to process ECG signal in realtime. In other words, the design of algorithm that exactly detects QRS wave using minimal computation and classifies PVC by analyzing the persons's physical condition and/or environment is needed. Thus, efficient QRS detection and PVC classification based on profiling method is presented in this paper. For this purpose, we detected QRS through the preprocessing method using morphological filter, adaptive threshold, and window. Also, we applied profiling method to classify each patient's normal cardiac behavior through hash function. The performance of R wave detection, normal beat and PVC classification is evaluated by using MIT-BIH arrhythmia database. The achieved scores indicate the average of 99.77% in R wave detection and the rate of 0.65% in normal beat classification error and 93.29% in PVC classification.