• 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.

• Proceedings of the KOSOMBE Conference
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• v.1996 no.05
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• pp.288-292
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• 1996

This paper describes far the detection of heart event that is, QRS complex and P wave which are result from heart activity. The proposed QRS detection method by using the spatial velocity was identified as having the 99.6% detection accuracy as well as fast processing time. Atrial flutter, coupled P wave, and noncoupled P wave as well as atrial fibrillation could be detected correctly by three different algorithms according to their origination farm. About 99.6% correction accuracy coupled P wave could be obtained and we could be found that most detection errors are caused by establishing wrong search interval.

• Proceedings of the KOSOMBE Conference
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• v.1994 no.12
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• pp.88-91
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• 1994

It is well known that multipoint and computerized intraoperative mapping systems improve the results of surgery for Wolff-Parkinson-White syndrome and show tremendous potential for opening an entirely new era of surgical intervention for the more common and lethal types of supraventricular tachyarrhythmias such as atrial flutter and atrial fibrillation. In addition, the ability to map and ablate the sometimes fleeting automatic atrial tachycardia is greatly enhanced by computerized mapping systems. In this study, we have developed 64 channel computerized data analysis system using microcomputer (Macintosh IIx) for basic research of electrophysiology and electrical propagation. The bipolar electrogram information is acquired from 64 cardiac sites simultaneously at a sampling rate of 1ksamples/sec with continuous and total data storage of up to 30 seconds. When the reference electrogram is selected and reference point is picked up, delay time from the reference point in displayed on two dimensional diagram of the heart. System design permits easy expansion to almost 256 simultaneous sites, This system is expected to enable us to study pathophysiology of cardiac arrhythmia and to improve the results of diagnosis and surgical treatment for cardiac arrhythmia.

• Journal of Chest Surgery
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• v.40 no.12
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• pp.811-816
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• 2007

Background: We analyzed our experience of arrhythmia surgery in patients with congenital heart disease. Material and Method: A retrospective review was performed on 43 consecutive patients with congenital heart disease, who underwent arrhythmia surgery between June 1998 and June 2006. Result: The median age at surgery was 52 years ($4{\sim}75$ years). The most frequent cardiac anomaly was an atrial septal defect (23/43, 53.5%). The types of arrhythmias were atrial flutter-fibrillation, intermittent non-sustainable ventricular tachycardia and others in 37, 2 and 4, respectively. Arrhythmia surgery consisted of a bi-atrial maze operation in 18 patients (modified cox maze III procedure in 5 patients, and a right side maze plus pulmonary vein cryo-isolation in 13), right side maze operation in 18 patients, cavo-tricuspid isthmus cryoablation for benign atrial flutter in 4 patients, right ventricular endocardial cryoablation in 2 patients and extranodal cryoablation for atrioventricular node re-entry tachycardia in 1 patient. The median follow-up was 23.8 months ($1{\sim}95.2$ months). There was no early mortality, and one late non-cardiac related death. The overall rates of restored sinus rhythm before discharge and $3{\sim}6$ months after surgery were 79% and 81%, respectively (bi-atrial maze group: 72% and 83%, right-side maze group: 77%, 77%). Conclusion: Arrhythmias associated with congenital heart disease can be safely treated surgically with an excellent intermediate-term outcome.

• Journal of Chest Surgery
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• v.35 no.11
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• pp.817-821
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• 2002

There are various surgical techniques in repairing Ebstein anomaly, but residual tricuspid regurgitation and compromized right heart function may ensue in some cases. We report our clinical experience of Ebstein anomaly and atrial flutter in a 19-year-old male patient who underwent simple modified tricuspid annuloplasty, hi-directional cavopulmonary shunt and cryoablation of cavotricuspid isthmus.

• Journal of Chest Surgery
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• v.48 no.1
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• pp.67-69
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• 2015

This is a report of a biatrial cardiac myxoma in a young man with a 10-month history of exertional dyspnea and palpitation. The echocardiogram revealed biatrial myxoma prolapsing through the mitral and tricuspid valves during diastole. All cardiac chambers were enlarged and dysfunctional. The electrocardiogram revealed a rapid ventricular response with atrial flutter rhythm. The masses were resected and diagnosed as myxoma by a histological examination. The follow-up echocardiogram revealed significant improvement in ventricular function and reduction in the cardiac chambers' volume. There was no evidence of myxoma recurrence. The most probable cause of the patient's heart failure was considered to be tachycardia-induced cardiomyopathy.

• Journal of Chest Surgery
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• v.37 no.8
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• pp.644-651
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• 2004

Background: Refractory atrial arrhythmias in patients late after the Fontan operation result in significant morbidity and mortality. We reviewed our experience with arrhythmia surgery in patients who had Fontan operation. Material and Method: Between July 1986 and December 2003, 275 early survivors after Fontan operation were reviewed. Fourteen patients underwent. arrhythmia surgery at reoperation after Fontan operation, and mean age at reoperation was 16.8$\pm$7.1 (range: 4.5 ∼ 30.6) years. Mechanisms of arrhythmia included atrial flutter in 8 patients, and atrial fibrillation in 2. Arrhythmia surgery has evolved from isthmus cryoablation in 12 patients to right-sided maze in 2 patients. Thirty-two patients. underwent prophylactic isthmus cryoablation concomitantly at initial Fontan operation. Result: Postoperative arrhythmias occurred in 68 patients (24.7%) among 275. There was no early and late mortality after the arrhythmia surgery. After redo Fontan operation, all patients maintained normal sinus rhythm. Atrial flutter recurred in 3 patients who had sinus conversion with medication and 7 required permanent pacemakers with a mean follow-up of 26.5$\pm$29.1 (range: 2 ∼ 73) months. All patients have improved to NYHA class I or II. After prophylactic cryoablation at initial Fontan operation, 29 patients (90.6%) had sinus rhythm, 1 patient had junctional tachycardia, 1 patient had sinus nodal dysfunction, and 1 patient had AV block with a mean follow-up of 51.3$\pm$19.8 (range: 4∼80) months. Conclusion: Redo Fontan operation, and concomitant arrhythmia surgery reduced atrial arrhythmias and improved NYHA functional classification.

• Journal of Chest Surgery
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• v.36 no.2
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• pp.73-78
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• 2003

The Fontan operation has undergone a number of major modifications and clinical results have been improving over time. Nevertheless, during the follow-up period, life-threatening complications develop and affect the long-term outcomes. Surgical interventions for these complications are needed and are increasing. Material and Method: From April 1988 to January 2000, 16 patients underwent reoperations for complications after Fontan operation. The mean age at reoperation was 8.8 :-5.5 years. Initial Fontan operations were atriopulmonary connections in 8 and total cavopulmonary connections in 8. Total cavopulmonary connections were accomplished with intracardiac lateral tunnel in 5 and extracardiac epicardial lateral tunnel in 3. Five patients had variable sized fenestrations. The reasons for reoperations included residual shunt in 6, pulmonary venous obstruction in 3, atrial flutter in 3, atrioventricular valve regurgitation in 2, Fontan pathway stenosis in 1, and protein-losing enteropathy in 1 Result: There were 3 early and late deaths respectively Patients who had residual shunts underwent primary closure of shunt site (n=2), atrial reseptation for separation between systemic and pulmonary vein (n=2), conversion to lateral tunnel (n=1), and conversion to one and a half ventricular repair (n=1). Four patients who had stenotic lesion of pulmonary vein or Fontan pathway underwent widening of the lesion (n=3) and left pneumonectomy (n=1) In cases of atrial flutter, conversion to lateral tunnel after revision of atriopulmonary connections was performed (n=3). For the atrioventricular valve regurgitation (n=2), we performed a replacement with mechanical valve. In one patient who had developed protein-losing enteropathy, aorto-pulmonary collateral arteries were obliterated via thoracotomy. Cryoablation was performed concomitantly in 4 patients as an additional treatment modality of atrial arrhythmia. Conclusion: Complications after Fontan operation are difficult to manage and have a considerable morbidity and mortality. However, more accurate understanding of Fontan physiology and technical advancement increased the possibility of treatment for such complications as well as Fontan operation itself. Appropriate surgical treatment for these patients relieved the symptoms and improved the functional class, Although the results were not satisfactory enough in all patients.

• Journal of Chest Surgery
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• v.14 no.1
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• pp.49-59
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• 1981

This is one case report of surgically treated partial atrioventricular canal. The 22 year-old male patient had no definitive history of frequent respiratory infection and cyanosis in his early childhood. Since his age of 7 years, dyspnea was manifested on exertion. First appearance of congestive heart failure was at his age of 16 years old. The physical examination revealed that the neck veins were distended and heaving of precordium. A thrill was palpable on the left 3rd-4th intercostal space extending from the sternal border toward the apex and Grade IV/VI systolic ejection murmur was audible on it. Neither cyanosis nor clubbing was noted. Liver was palpable about 5 finger breadths. Chest X-ray revealed increased pulmonary vascularity and severe cardiomegaly (C-T ratio = 74%). EKG revealed LAD, clockwise rotation, LVH and trifascicular block. Echocardiogram showed paradoxical ventricular septal movement, narrowed left ventricular outflow tract and abnormal diastolic movement of the anterior leaflet of mitral valve. Right heart catheterization resulted in large left to right shunt (Qp : Qs = 5.7: 1), ASD and moderate pulfllonary hypertension. Finally, left ventriculogram revealed typical goose neck appearance of left ventrlcalar outflow tract. On Oct. 10, 1980, open heart surgery was performed. Operative findings were: 1. Large primum defect ($6{\times}5$ Cm in diameter) 2. Cleft on the anterior leaflet of mitral valve. 3. The upper portion of ventricular septum was descent but no interventricular communication. 4. Downward attachment of the atrioventricular valves on the ventricular muscular septum. 5. Medium sized secumdum defect ($2{\times}1$ Cm in diameter). The cleft was repaired with 4 interrupted sutures. The primum defect was closed with Teflon patch and the secundum defect was closed with direct suture closure. Postoperatively atrial flutter-fibrillation in EKG and Grade U/VI apical systolic murmur were found. The postoperative course was uneventful and discharged on 29th postoperative day in good general conditions.

• Clinical and Experimental Pediatrics
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• v.58 no.11
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• pp.440-445
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• 2015

Purpose: Chest pain is common in children and adolescents and is a reason for referral to pediatric cardiologists. Although most cases of chest pain in these age groups are benign and do not require treatment, timely diagnosis is important not to miss life-threatening diseases requiring prompt treatment. We investigated certain clinical characteristics that may be useful in the diagnosis of such critical diseases. Methods: Patient medical records between July 2006 and September 2013 were retrospectively examined. We included 517 patients who presented with chest pain to the Department of Pediatrics at Kyung Hee University Hospital in Gangdong. Results: Most cases of chest pain were idiopathic in origin (73.6%), followed by cases with respiratory (9.3%), musculoskeletal (8.8%), cardiac (3.8%), gastrointestinal (2.9%), and psychiatric (1.4%) causes. In 6 patients (1.2%) with air-leak syndrome including pneumothorax or pneumomediastinum, the pain was abrupt, continuous, and lasted for a short period of 1-2 days after onset in the older adolescents. Of the patients with cardiac pain, 13 had cardiac arrhythmias (65.0%), 6 had congenital heart diseases (30%), and 1 had coronary aneurysms caused by Kawasaki disease (5.0%). One patient with atrial flutter had only symptoms of syncope and chest pain. Conclusion: The abrupt, continuous chest pain of a short duration in the older children was characteristic of air-leak syndrome. In patients with pneumomediastinum, radiological diagnosis was difficult without careful examination. Combined syncope should not be neglected and further cardiac workup is essential in such patients.