• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.1
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• pp.16-22
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• 2010

Electrocardiogram(ECG) analysis and arrhythmia recognition are critical for diagnosis and treatment of ill patients. Cardiac arrhythmia is a condition in which heart beat may be irregular and presents a serious threat to the patient recovering from ventricular tachycardia (VT) and ventricular fibrillation (VF). Other arrhythmias like atrial premature contraction (APC), Premature ventricular contraction (PVC) and superventricular tachycardia (SVT) are important in diagnosing the heart diseases. This paper presented new method to classify various arrhythmias contrary to other techniques which are limited to only two or three arrhythmias. ECG is decomposed into Intrinsic Mode Functions (IMFs) by Empirical Mode Decomposition (EMD). Burg algorithm was performed on IMFs to obtain AR coefficients which can reduce the dimension of feature vector and utilized as Multi-class SVM inputs which is basically extended from binary SVM. We chose optimal parameters for SVM classifier, applied to arrhythmias classification and achieved the accuracies of detecting NSR, APC, PVC, SVT, VT and VP were 96.8% to 99.5%. The results showed that EMD was useful for the preprocessing and feature extraction and multi-class SVM for classification of cardiac arrhythmias, with high usefulness.

• The Journal of Internal Korean Medicine
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• v.33 no.2
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• pp.160-171
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• 2012

Background and Objective : Warfarin is the standard anticoagulation treatment for atrial fibrillation, venous thromboembolism (VTE), and mechanical heart valves. Close monitoring of the International Normalized Ratio (INR) is required due to the drug's very narrow therapeutic window. Many factors can affect INR levels. Drug and food interactions are frequently cited as causes of adverse events with warfarin. We discussed interactions between herbs and warfarin studied in this research. Methods : In this review, PubMed was used to search medical journals. Keywords "warfarin AND interaction" were applied. Results : 55 articles were included. The possibility of correlation between warfarin and single herbal medicines such as Salviae Miltiorrhizae Radix, Angelicae Gigantis Radix, Ginseng Radix Alba, Lycii Fructus, Ginkgo Folium, Menthae Herba, Trigonellae semen was suggested. Furthermore, some herbal compounds interacting with warfarin were reported. The conclusion of studies reporting the effect of herbal medicine on warfarin were controversial due to small size or quality of research. Conculsions : We suggest that we should prescribe therapeutic herbal medicines to patients using warfarin more carefully and do INR follow-up regularly.

• Journal of Korean Neurosurgical Society
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• v.59 no.4
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• pp.379-384
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• 2016

Objective : Mechanical thrombectomy (MT) for acute intracranial internal carotid artery (ICA) occlusion is often complicated by difficult revascularization and non-involved territory embolization possibly related with larger clot-burden. This study aims to evaluate the efficacy of proximal aspiration thrombectomy (PAT) using a balloon-tipped guide catheter for clot-burden reduction in such cases with period-to-period analysis (period 1 : standard MT without PAT; period 2 : PAT first, then standard MT for the remaining occlusion). Methods : Eighty-six patients who underwent MT for acute intracranial ICA occlusion were included in this analysis from the prospectively maintained stroke registry (33 patients in period 1 and 53 in period 2). In period 2, 'responder' was defined as a case where some amount of clot was retrieved by PAT and the following angiography showed partial or full recanalization. Results : Fifteen of fifty-three patients in period 2 (28.3%) were 'responders' to PAT. There was a significantly higher incidence of atrial fibrillation in the 'responder' subgroup. Period 2 showed a significantly shorter puncture-to-reperfusion time (94.5 minutes vs. 56.0 minutes; p=0.002), a significantly higher Thrombolysis in Cerebral Infarction of 2b-3 reperfusion (45.5% vs. 73.6%; p=0.009), but only a trend for better 3-month favorable outcome (mRS 0-2; 36.4% vs. 54.7%; p=0.097). There was no increase in the incidence of procedure-related complications or intracranial hemorrhage in period 2. Conclusion : A strategy of PAT before standard MT may result in shorter puncture-to-reperfusion time and better angiographic outcome than a strategy of standard MT for acute intracranial ICA occlusion.

• Progress in Superconductivity
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• v.13 no.1
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• pp.1-6
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• 2011

Measurement of magnetic signals generated from electric activity of myocardium provides useful information for the functional diagnosis of heart diseases. Key technical component of the magnetocardiography (MCG) technology is SQUID. To measure MCG signals with high signal-to-noise ratio, sensitive SQUID magnetic field sensors are needed. Present magnetic field sensors based on Nb SQUIDs have field sensitivity good enough to measure most of MCG signals. However, for accurate measurement of fine signal pattern or detection of local atrial fibrillation signals, we may need higher field sensitivity. In addition to field sensitivity, economic aspect of the SQUID system is also important. To simplify the SQUID readout electronics, the output voltage or flux-to-voltage transfer of SQUID should be large enough so that direct measurement of SQUID output can be done using room-temperature preamplifiers. Double relaxation oscillation SQUID (DROS), having about 10 times larger flux-to-voltage transfers than those of DC-SQUIDs, was shown to be a good choice to make the electronics compact. For effective cancellation of external noise inside a thin economic shielded room, first-order axial gradiometer with high balance, simple structure and long-baseline is needed. We developed a technology to make the axial gradiometer compact using direct bonding of superconductive wires between pickup coil and input coil. Conventional insert has mechanical support to hold the gradiometer array, and the dewar neck has equal diameter with the dewar bottom. Boiling of the liquid He can generate mechanical vibrations in the gradiometer array due to mechanical connection structure. Elimination of the mechanical support, and direct mounting of the gradiometer array into the dewar bottom can reduce the dewar neck diameter, resulting in the reduction of liquid He consumption.

• Journal of Chest Surgery
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• v.22 no.6
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• pp.1001-1012
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• 1989

In 1968, Carpentier and his associates introduced glutaraldehyde as a compound for preparing cardiac tissue valve, and this technique has provided a considerably more suitable and durable tissue valve substitute. To increase further durability of valve tissue, Reis and his colleagues designed a flexible stent to reduce the stress on the heterogeneous tissue valve mounted. However with the advent of more innovative mechanical valve currently, many bioprosthetic valves are being substituted by mechanical valves at our department of cardiothoracic surgery because of bioprosthetic valve failure. Main cause of bioprosthetic valves failure were calcification or/and tear of tissue valves. The purpose of this retrospective study is to clarify the relationship between the patients clinical profile during implantation of tissue valves and pathologic features of the failed bioprosthetic valve. From March, 1982 through June, 1988, 53 bioprosthetic heart valves that had been ex-planted from 45 patients at the department of cardiac surgery of Yonsei University Hospital were subjected to this study. The patients were 10 to 65 year-old [mean age: 30.3 yr] with 17 males and 28 females. Re-replacements of prosthetic valves were carried out twenty nine in mitral position, eight in aortic position and eight in both aortic and mitral position simultaneously. The grading and location for calcification of valves were verified by radiograms. The calcification of the explanted valves leaflets was graded from 0 to 4 plus according to Cipriano and associates method. The types of tear and perforation of leaflet were classified into four types as Ishihara has adopted initially in 1981. In younger age group under thirty three years, explanted tissue valves were significantly more affected in terms of grades of severity of valve calcification as compared with older age group [p < 0.035]. Valve calcification appeared more severe in male as compared to female [p< 0.002]. Ionescu-Shiley bovine pericardial bioprosthetic valves showed more severe calcification than Hancock porcine tissue valves [p< 0.035]. Calcium deposit was found very prevalent at the area of commissural attachment [86 % of all]. Type I of valve rupture was shown to be related with simultaneous calcification. However, the relation of explanted valve position, duration of implanted prosthetic valve, atrial fibrillation and anticoagulant therapy to the severity of bioprosthetic valve calcification were not significantly clear statistically [p > 0.05].

• Journal of Chest Surgery
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• v.4 no.1
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• pp.11-24
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• 1971

Eighty-four cases of mitral commissurotomy were done in this department between October 1958 and September 1970. Therc wcre 54 males and 30 females. Six cases were under the age of 20 years. Prcoperativc embolization occurred in 9. 5% of the cases. consisting of 8. 3% cerebral and 1.2% peripheral embolization. Intraoperative and postoperative cmbolization occurred in 4.7% of the cases, with 1. 2% cerebral and 3.5% peripheral embolism. Two out of three postopeative embolism cases expired, one of which was caused by septic cerebral embolism due to valve vegetation nnd the other by mesenteric embolism. Atrial fibrillation was 1loted ill 43% of the case. Seventy closed mitral commissurotomy was done by left appendegeal approach with finger fracture method or Bailey's guillotine valvotome. Fourteen open mitral commissurotomy cases were done either by right side approach or median sternotomy, three of which were reoperation cases after blind mitral commissurotomy. One out of 14 cases were operated on with open mitral commissurotomy and concomitant open aortic valve bicuspidalization, This case expired due to severe serum hepatitis ten days after operation. Thirty-two per cent of valve calcification was noted during operation and one of which had marked vegetation on the valve cusps too. Operative mortality was 1.4% in blind mitral commissurotomy and 14% in open mitral commissurotomy. Over-all mortality in the entire series was 3.5%. One case among the blind commissurotomy cases expired during operation due to left inferior pulmonary vein laceration and death was caused in two open mitral commissurotomy cases by coronary artery airembolism. Three hospital death occurred in blind operation group, one due to coronary embolism, and two by hepatic failures. Three hospital death among open heart surgery cases were caused by hepatic failure in two and cerebral embolism in one cases. ln most of the survivors improved functional capacity and exercise lolerance were noted.

• Journal of The Korean Society of Clinical Toxicology
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• v.11 no.2
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• pp.119-126
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• 2013

Purpose: The aim of this study was to evaluate the clinical characteristics and outcome of patients who presented to the emergency department (ED) with cardiotoxicity caused by ingestion of Himalayan mad honey. Methods: Medical records of 12 patients who presented to the ED from January 1, 2005 to December 31, 2012 with cardiotoxicity caused by ingestion of Himalayan mad honey were retrospectively reviewed. Results: The mean age of patients was 54.5 years and 58.3% were men. The median amount of mad honey ingested was 30.0 cc, and the mean time from ingestion to onset of symptoms was 39.4 minutes. All patients had hypotension and bradycardia upon arrival in the ED. The initial electrocardiogram showed sinus bradycardia in seven patients, junctional bradycardia in four patients, and atrial fibrillation with slow ventricular response in one patient. Four patients were treated with intravenous normal saline solution only. Eight patients were treated with intravenous normal saline solution and atropine sulfate in a dose ranging from 0.5 to 2.0 mg. Blood pressure and pulse rate returned to normal limits within 24 hours in all patients. Conclusion: Our study showed that all patients with cardiotoxicity caused by ingestion of Himalayan mad honey had severe hypotension, bradycardia, and bradyarrythmias, including sinus bradycardia and junctional bradycardia and all patients responded well to conservative treatment, including intravenous normal saline solution and intravenous atropine sulfate.

• Journal of Life Science
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• v.17 no.11
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• pp.1539-1546
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• 2007

We have investigated whether the supplement of magnesium to cold blood cardioplegia improves myocardial protection. Sixty patients scheduled for elective valvular heart surgery were randomly assigned to a control group (n=30) which received conventional cold blood cardioplegia and an Mg group (n=30) which received cold blood cardioplegia supplemented with 2 g of magnesium sulfate. Electrolytes levels including $Mg^{++}$, hematological and biochemical variables, cytokines, myocardial marker levels, and postoperative outcomes were compared between two groups before, during or idler operation. $Mg^{++}\;and\;Ca^{++}$ levels in the Mg group were higher than those of the control group after surgery. The total WBC counts, CK-MB, troponin-I and Interleukin-6 levels in the Mg group were lower than those of the control group after surgery. Postoperative incidence of atrial fibrillation was lower in the Mg group compared with the control group. These results showed that $Mg^{++}$ attenuated inflammatory reaction, myocardial damage, and hypomagnesemia during valvular surgery and reduced postoperative arrhythmia incidence without side effects.

• Journal of Chest Surgery
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• v.49 no.5
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• pp.350-355
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• 2016

Background: Mitral stenosis (MS) remains one of the important heart diseases. There are many factors that influence the clinical outcomes, and little is known about how left ventricular (LV) dysfunction clinically affects the prognosis of the patient with MS after mitral valve replacement (MVR). We reviewed our clinical experiences of MVR in patients with MS who had LV dysfunction. Methods: Between January 1991 and January 2013, 110 patients with MS who underwent MVR were analyzed and divided into two groups according to ejection fraction (EF). Group 1 ($EF{\leq}45%$) included 13 patients and group 2 (EF>45%) included 97 patients. Results: Thromboembolism occurred in 8 patients after MVR (group 1: n=3, 23.1%; group 2: n=5, 5.2%) and its incidence was significantly higher in group 1 than in group 2 (p=0.014). There were 3 deaths each in groups 1 and 2 during follow-up. The overall rate of cardiac-related death in group 1 was significantly higher than in group 2 (group 1: n=3, 23.1%; group 2: n=3, 3.1%; p=0.007). The cumulative survival rate at 1 and 15 years was 83.9% and 69.9% in group 1 and 97.9% and 96.3% in group 2 (p=0.004). The Cox regression analysis revealed that survival was significantly associated with postoperative stroke (p=0.011, odds ratio=10.304). Conclusion: This study identified postoperative stroke as an adverse prognostic factor in patients with MS after MVR, and a s more prevalent in patients with LV dysfunction. Postoperative stroke should be reduced to improve clinical outcomes for patients. Preventive care should be made in multiple ways, such as management of LV dysfunction, atrial fibrillation, and anticoagulation.

• Journal of Trauma and Injury
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• v.21 no.2
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• pp.85-90
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• 2008

Purpose: Supraventricular arrhythmia is a well-known complication of cardiothoracic surgery, and is common in patients wirth underlying cardiovascular disease. Also, it's treatment and prognosis are well known. However the incidence, the contributing factors, and the prognosis for supraventricular arrhythmias in noncardiothoracic surgical patients are less well known. This study was undertaken to investigate the incidence, the clinical presentation, the prognosis, and the factors comtributing to the prognosis for supraventricular arrhythmia in the surgical intensive care unit. Methods: We performed a retrospective study of 34 patients with newly developed or aggravated supraventricular arrhythmias in the surgical intensive care unit between March 2004 and February 2005. The incidence, the risk factors, and the prognosis of supraventricular arrhythmias were analyzed. Results: During a 12month period, the incidence of supraventricular arrhythmia was 1.79% (34/1896). Most patients had pre-existing cardiovascular disease and sepsis. The mortality rate was 29.4%, and the most common cause of death was multiple organ failure due to septic shock. The mean value of the APACHE II score was 20.9, and the surgical intensive care unit and the hospital lengths of stay were 9.9 days and 25.8 days, respectively. The APACHE II score measured when the arrhythmia developed was a significant factor in predicting mortality, Conclusion: Supraventricular arrhythmias result in increased mortality and increased length of stay in both the surgical intensive care unit and the hospital. The arrhythmia itself did not cause death, but a high APACHE II score incicated a poor prognosis. This may reflect the severity of the illness rather than an independent contributor to mortality.