• Journal of Chest Surgery
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• v.52 no.2
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• pp.61-69
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• 2019

Background: Scarce data have been reported on the efficacy of concomitant atrial fibrillation (AF) ablation in patients undergoing bioprosthetic valve replacement. Methods: From 2001 and 2014, 146 consecutive patients ($69.3{\pm}9.4years$, 84 females) who underwent bioprosthetic heart valve replacement concomitant with AF ablation were assessed. We evaluated long-term rhythm and valve-related outcomes. Results: During 49.1 months of follow-up (interquartile range, 22.5-96.8 months), 7 in-hospital and 49 (6.7% per person-year) post-discharge deaths occurred. The thromboembolic event-free survival rate at 5 years was $79.2%{\pm}3.5%$. The freedom from AF recurrence rate at 5 years was $59.8%{\pm}4.9%$. Multivariate analysis showed that old age (hazard ratio [HR], 1.06; 95% confidence interval [CI], 1.02-1.11; p=0.002), previous cardiac operation (HR, 3.01; 95% CI, 1.22-7.43; p=0.02), and a large left atrial (LA) dimension (HR, 1.02; 95% CI, 1.00-1.05; p=0.045) were significantly associated with AF recurrence. Conclusion: The overall long-term clinical outcomes in these predominantly elderly patients undergoing AF ablation concomitantly with bioprosthetic valve replacement were satisfactory; however, AF recurrence was frequent. Older age, a history of prior cardiac surgery, and large LA size were associated with an increased risk of AF recurrence.

• Korean Circulation Journal
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• v.48 no.12
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• pp.1033-1080
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• 2018

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia in the general population. The Korean Heart Rhythm Society organized a Korean AF Management Guideline Committee and analyzed all available studies regarding the management of AF, including studies on Korean patients. This guideline is based on recent data of the Korean population and the recent guidelines of the European Society of Cardiology, European Association for Cardio-Thoracic Surgery, American Heart Association, and Asia Pacific Heart Rhythm Society. Expert consensus or guidelines for the optimal management of Korean patients with AF were achieved after a systematic review with intensive discussion. This article provides general principles for appropriate risk stratification and selection of anticoagulation therapy in Korean patients with AF. This guideline deals with optimal stroke prevention, screening, rate and rhythm control, risk factor management, and integrated management of AF.

• Progress in Superconductivity
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• v.7 no.1
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• pp.28-35
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• 2005

We propose a method to measure atrial arrhythmias (AA) such as atrial fibrillation (Afb) and atrial flutter (Afl) with a SQUID magnetocardiograph (MCG) system. To detect AA is one of challenging topics in MCG. As the AA generally have irregular rhythm and atrio-ventricular conduction, the MCG signal cannot be improved by QRS averaging; therefore a SQUID MCG system having a high SNR is required to measure informative atrial excitation with a single scan. In the case of Afb, diminished f waves are much smaller than normal P waves because the sources are usually located on the posterior wall of the heart. In this study, we utilize an MCG system measuring tangential field components, which is known to be more sensitive to a deeper current source. The average noise spectral density of the whole system in a magnetic shielded room was $10\;fT/{\surd}Hz(a)\;1\;Hz\;and\;5\;fT/{\surd}Hz\;(a)\;100\;Hz$. We measured the MCG signals of patients with chronic Afb and Afl. Before the AA measurement, the comparison between the measurements in supine and prone positions for P waves has been conducted and the experiment gave a result that the supine position is more suitable to measure the atrial excitation. Therefore, the AA was measured in subject's supine position. Clinical potential of AA measurement in MCG is to find an aspect of a reentry circuit and to localize the abnormal stimulation noninvasively. To give useful information about the abnormal excitation, we have developed a method, separative synthetic aperture magnetometry (sSAM). The basic idea of sSAM is to visualize current source distribution corresponding to the atrial excitation, which are separated from the ventricular excitation and the Gaussian sensor noises. By using sSAM, we localized the source of an Afl successfully.

• Journal of Chest Surgery
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• v.24 no.5
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• pp.445-450
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• 1991

Forty eight patients diagnosed as atrial septal defect, had been operated from April 1986 to December 1990 at the Department of Thoracic and Cardiovascular Surgery, Inha University Hospital, were analysed retrospectively. Of the 48 patients, 12 patients, were male and 36 patients were female, Their ranged from 8 months to 51 years old, and the mean was 18.0 years old. The proceeding two symptoms were exertional dyspnea and frequent upper respiratory infection. But 10 patients [20.8%] were asymptomatic. Electrocardiographic findings were regular sinus rhythm in 100.0%, RVH in 29.2%, incomplete RBBB in 27.1%, and first degree AV block in 2.1%. Hemodynamic studies were performed in 38 of 48 patients. Significant pulmonary hypertension[over 50mmHg in systolic pulmonary arterial pressure], which is the most serious risk factor, was developed in 4 patients[8.3%]. There was statistical significance between size of defect[cm2/BSA-M2] and systolic pulmonary arterial pressure[sPAP] retrospectively[p=0.036]. We could not find the correlationship between age and Qs % size. Anatomically, secundum type constituted 97.9%, in which 43 patients were PFO type[91.6%] and 3 patients were IVC type[6.3%]. 38 of 48 ASD patients were repaired with patch closure[72.9%] and remains were repaired with direct closure[27.1%]. The operative result was excellent except two cases of transient postoperative arrhythmia. There was no operative mortality.

• Journal of Chest Surgery
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• v.33 no.11
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• pp.876-880
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• 2000

배경: Maze수술은 승모판 질환에 동반되는 심방세동의 효과적인 치료방법으로 알려져있다. 이 연구는 승모판 수술과 심방세동 수술을 동시에 시행한 환자에서 심방세동 수술 후 중기적인 결과와 그 재발 여부를 조사하였다. 대상 및 방법: 심방세동 수술과 승모판 수술을 받은 11예의 환자(10예는 류마티스성 승모판 질환)를 대상으로 하였다. Maze II 수술 및 그 변형수술을 6예에서 시행했고, Maze III 수술 및 그 변형수술을 5예에서 시행하였다. 심방세동 수술 후 좌심방의 수축정도를 심방세동 수술 없이 승모판 수술만으로 동율동을 얻은 경우와 비교하였다. 결과: Maze II 수술을 받은 환자 6예 중 5예(83.3%)에서, maze III 수술을 받은 환자 5예 모두에서 동율동을 회복하였다(전체적으로 90.9%). 전자의 1예(20%)와 후자의 2예(40%)에서 수술 후 각각 23, 2, 13개월만에 심방세동이 재발하였다. 그 후 다시 2예는 동율동으로 전환되었으나, 1예는 재발된 심방세동을 그대로 유지하고 있다. 변형술을 받은 3예에서는 심방세동의 재발이 없었다. Maze 수술 후 4예(40%)에서만 좌심방의 수축기능을 보였으며, maze 수술 후 좌심방 수축 정도(승모판의 A파의 속도)도 maze 수술 없이 승모판 수술과 항부정맥제 투여로 동율동을 회복한 경우보다 낮았다. 결론: 심방세동을 동반한 승모판 수술 환자에서 maze 수술로써 심방세동으로부터 동율동을 회복할 수 있으나 중기적으로 재발할 수 있으며, maze 수술 후 좌심방 수축정도는 상당히 떨어질 수 있다고 생각된다.

• Journal of Chest Surgery
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• v.26 no.7
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• pp.526-531
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• 1993

Sixty-one consecutive patients with coronary artery bypass graft for myocardial revascularization were retrospectively reviewed to analyze various pattern of postoperative complication and death during hospital stay from Nov. 1988 to Oct. 1992. Fortytwo of the patients were male and nineteen female. The mean age was 56 and 51 years in male and female. Preoperative diagnosises were unstable angina in 14 of patients, stable angina in 28, postmyocardial infarction state in 15, and state of failed percutaneous transluminal coronary angioplasty in 4. 141 stenosed coronary arteries were bypassed with use of 20 pedicled internal mammary artery and 124 reversed saphenous vein grafts. Postoperative complications and perioperative death were as follows: 1. Of 61 patients undergoing operation, peri and postoperative over all complication occured in 15 patients [ 25% ]; newly developed myocardial infarction in 4, intractable cardiac arrhythmia including atrial fibrillation and frequent ventricular premature contraction in 3, bleeding from gastrointestinal tract in 2, persistent vegetative state as a sequele of brain hypoxia in 1, wound necrosis in 1, left hemidiaphragmatic palsy in 3 and poor blood flow through graft in 2. 2. Operative mortality was 8%[5 patients]. 3 out of these died in operating room; 1 patient by bleeding from rupture of calcified aortic wall, 1 by air embolism through left atrial vent catheter, 1 by low cardiac output syndrome. 2 patients died during hospital stay; 1 by acute respiratory distress syndrome with multiuple organ failure, 1 by brain death after delayed diagnosis of pericardial tamponade.

• Journal of Chest Surgery
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• v.38 no.6 s.251
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• pp.438-440
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• 2005

The incidence of primary cardiac tumor is rare, furthermore the cardiac tumor which cause arrhythmia is very rare. We presesent a case of cardiac lipoma combined with paroxysmal atrial tachycardia.

• Journal of Chest Surgery
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• v.31 no.9
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• pp.855-860
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• 1998

Background: Adequate exposure of the mitral valve is a prerequisite for mitral procedures including the repair. An extended transseptal approach in mitral valvular operations is known to have certain technical advantages in recent years because of the anatomic posterior location of the mitral valve, especially in reoperations and in the presence of the small atrium in spite of the possibility of arrhythmia due to injury of sinus nodal artery. Material and Method: We compared the preoperative status, operative, and postoperative factors among patients in two study groups, transseptal only (Group I, n=10) and extended transseptal approach(Group II, n=25). Result: There were no differences in age, sex, NYHA functional class, left atrial size, and left ventricular function. The incidence of the redo-operation was high and early postoperative arrhythmia, which was improved later, appeared in 3 patients in Group II, but not in Group I. Conclusion: We believe that atrial septal incision could be extended up to the atrial roof whenever exposure of the mitral valve during a transseptal approach is inadequate because the late results were similar.

• 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.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.2
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• pp.450-460
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• 2017

T wave is cardiac parameters that represent ventricular repolarization, it is very important to diagnose arrhythmia. Several methods for detecting T wave have been proposed, such as frequency analysis and non-linear approach. However, detection accuracy is at the lower level. This is because of the overlap of the P wave and T wave depending on the heart condition. We propose T wave detection algorithm based on target area extraction through QRS cancellation and moving average. For this purpose, we detected Q, R, S wave from noise-free ECG(electrocardiogram) signal through the preprocessing method. And then we extracted P, T target area by applying decision rule for four PAC(premature atrial contraction) pattern another arrhythmia through moving average and detected T wave using RT interval and threshold of RR interval. The performance of T wave detection is evaluated by using 48 record of MIT-BIH arrhythmia database. The achieved scores indicate the average detection rate of 95.32%.