• Clinical and Experimental Pediatrics
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• v.60 no.12
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• pp.390-394
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• 2017

Purpose: Atrioventricular nodal reentry tachycardia (AVNRT) is less common in pediatric patients than in adult patients. Thus, data for pediatric AVNRT patients are insufficient. Hence, we aimed to analyze the patient characteristics, treatment, and any recurrences in pediatric AVNRT patients. Methods: We reviewed the records of 50 pediatric AVNRT patients who had undergone radiofrequency catheter ablation (RFCA) between January 1998 and December 2016 at a single regional center. The patients were aged ${\leq}18years$. Results: Among 190 pediatric patients who underwent RFCA for tachyarrhythmia, 50 (26.3%; mean age, $13.4{\pm}2.6years$) were diagnosed as having AVNRT by electrophysiological study. Twenty-five patients (25 of 50, 50%) were male. Twenty patients (20 of 50, 40%) used beta-blockers before RFCA. All patients had no structural heart disease except 1 patient with valvular aortic stenosis and coarctation of the aorta. RFCA was performed using the anatomic approach under fluoroscopic guidance. The most common successfully ablated region was the midseptal region (25 of 50, 50%). Slow pathway (SP) ablation and SP modulation were performed in 43 and 6 patients, respectively. Complication occurred in 1 patient with complete atrioventricular block. During follow-up, 6 patients had recurrence of supraventricular tachycardia, as confirmed by electrocardiography. Among them, 5 underwent successful ablation at the first procedure. In 1 patient, induction failed during the first procedure. Conclusion: RFCA is safe and effective in pediatric AVNRT patients. However, further research is needed for establishing the endpoints of ablation in pediatric AVNRT patients and for identifying risk factors by evaluating data on AVNRT recurrence after RFCA.

• Journal of Chest Surgery
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• v.27 no.3
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• pp.230-233
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• 1994

A 21-year-old man with atrioventricular[AV] reentry tachycardia secondary to concealed accessory AV connection underwent surgical division of two accessory pathways following failure of radiofrequency catheter ablation. pathways were located in the left free wall area.Before cardiopulmonary bypass, the epicardial mapping confirmed the existence and localization of two accessory pathways. The patient was approached through a left atriotomy with a dissection of the left free wall area beginning with an internal mapping was carried out after separation from cardiopulmonary bypass to confirm the absence of retrograde conduction of accessory pathway. Five weeks after surgery, the electrophysiololgic study demonstrated no retrograde conduction through two accessory pathways.

• Journal of Chest Surgery
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• v.25 no.9
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• pp.905-911
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• 1992

Automatic junctional tachycardia is one of common atrial arrhythmia after open heart surgery which is often refractory to antiarrhythmic agents. We have experienced refractory automatic junctional tachycardia in two patients. In the first, it occured after cryosurgery for AV nodal reentry tachycardia and simultaneous dissection of a posterior septal bypass tract. In the second, it complicated the postoperative course of a patient who received intracardiac repair for double outlet right ventricle, ventricular septal defect, and pulmonary stenosis. Conventional therapy with atrial pacing, verapamil, digoxin, and electrical cardioversion were ineffective. Therefore, amiodarone was administered intravenously and it controlled automatic junctional tachycardia. The need for accurate and rapid diagnosis of this condition along with results of treatment are discussed.

• Clinical and Experimental Pediatrics
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• v.46 no.1
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• pp.51-55
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• 2003

Purpose : We intended to find out the role of transesophageal atrial pacing in evaluation of infants and children with palpitation of unknown origin. Methods : We tried transesophageal atrial pacing study in 69 infants and children with palpitation, in whom tachycardia wasn't documented in electrocardiogram and reviewed retrospectively the records of transesophageal pacing and medical records of theses patients to find out the induction rate of tachycardia by transesophageal atrial pacing and the possible mechanism of tachycardia if induced. Results : In 70.1% infants and children with palpitation, tachycardia was induced, so we could conclude that tachycaridia was the cause of palpitation in these cases. In most cases, tachycardia was induced by rapid atrial pacing, and in 21% by using isoproterenol. Tachycardia induction rate was higher in <6-year-old children than ${\geq}6$-year-old children(P<0.05). In cases of the induced, we reviewed the mechanism of tachycardia. Of these induced tachycardias, 53.2% is atrioventricular reentry tachycardia, 34.0% were atrioventricular nodal reentry tachycardia, and 12.8% were idiopathic left ventricular tachycardia. Invasive electrophysiologic study was done to 10 patients of those induced. The results of electrophysiologic study and transesophageal pacing and recording were the same except for one patient. Conclusion : Transesophageal atrial pacing and recording is a less invasive, safe and useful method to find out the cause of palpitation and the mechanism of tachycardia in infants and children.

• 한국초전도학회:학술대회논문집
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• v.15
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• pp.50-50
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• 2005

• Journal of Chest Surgery
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• v.29 no.6
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• pp.639-645
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• 1996

A 14-year-old male patient with previous surgical repair of tetralogy of Fallot was admitted with hemodynamically significant ventricular tachycardia (VT). On preoperative electrophysiologic study (EPS), the morphology of documented VT was RBBB of vertical axis with 320 msec cycle length. The endocardial mapping during VT delineated the origin of VT at right ventricular outflow tract (RVOT), where the patch was attached. The clinical VT had a clockwise reentry circuit around the patch with the earliest activation at the same site seen during the preoperative EPS. The previously placed right ventricular outflow patch and fibrous tissue were removed. During a postoperative EPS, it was no longer possible to induce the VT. Ventricular tachycardia following repair of tetralogy of Fallot seen in this patient was caused by a macro-reentry around the right ventricular outflow patch. We were able to ablate the VT with the aid of a detailed mapping of its epicardial activation sequence.

• 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.1997 no.11
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• pp.222-227
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• 1997

To diagnose cardiac arrhythmia owing to reentry mechanism, cardiac conduction system was modeled by modified Hidden Markov modeled by evaluated. First, simulation of transient conduction states and output waves were made with initially assumed parametric values of cardiac muscle repolariztion time, conduction velocity and its automaticity. The output was a series of onset time and the name of the wave. Parameters determined the rate of beating, lengths of wave intervals, rate of abnormal beats, and the like. Several parameter sets were found to simulate normal sinus rhythm, supraventricular /ventricular tachycardia, atrial /vetricular extrasystole, etc. Then, utilizing the estimation theorems of Hidden Markov Model, the best conduction path was estimated given the previous output. With this modified estimation method, close matching between the simulated conduction path and the estimated one was confirmed.