• Clinical and Experimental Pediatrics
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• v.50 no.11
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• pp.1085-1090
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• 2007

Purpose : Radiofrequency catheter ablation (RFCA) has become an effective therapeutic modality for treating pediatric tachyarrhythmias. Using conventional RFCA catheters, ablation of parahisian accessory pathways may be difficult and have high risk for heart block. We reviewed the efficacy and complications of the RFCA in children and adolescent with arrhythmias including parahisian accessory pathways. Methods : We studied 48 patients (aged 2 years to 20 years) who had undergone RFCA from August 2003 to March 2007. We reviewed clinical findings, electrophysiologic studies, RFCA data, complications, and follow-up results of the patients. Results : Mean age of the patients was 13.1 years. Numbers and types of arrhythmias (age, acute success rate) were as follows: 19 WPW syndrome including 5 parahisian accessory pathways ($13.7{\pm}4.6yr$, 18/19), 11 atrioventricular reentrant tachycardia with concealed bypass tract ($12.3{\pm}5.0yr$, 10/11), 13 atrioventricular nodal reentrant tachycardia ($12.6{\pm}4.4yr$, 13/13), 4 atrial flutter ($13.0{\pm}7.4yr$, 3/4), and 1 ventricular tachycardia (20 yr, 1/1). Associated cardiac structural lesion was not detected in 48 patients. The recurrence rate was 6.5%, and the final success rate was 93.8%. Conclusion : These results suggest that RFCA is a highly effective treatment method in children and adolescent with tachyarrhythmia.

• Journal of Chest Surgery
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• v.37 no.6
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• pp.467-473
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• 2004

Background: The sinus conversion rate after the maze procedure in chronic atrial fibrillation using radiofrequency energy is lower than with either conventional 'cut and saw' technique or cryothermia. The creation of incomplete transmural lesions due to poor tissue-catheter contact is thought to be the main cause. To address this problem, the current study was aimed to evaluate the effectiveness of a specially constructed compression device designed to enhance tissue catheter contact during unipolar radiofrequency catheter ablation. Material and Method: Circum-ferential right auricular epicardial lesions were created with a linear radiofrequency catheter in 10 anesthetized pigs. A device specially designed to increase contact by compression of the catheter to the atrial wall was used in 5 pigs (study group). This device was not used in the control group (5 pigs). Conduction block across the right auricular lesion was assessed by pacing, and the transmurality of the lesions were confirmed by microscopic examination. Result: Conduction block was observed in a total of 8 pigs; 5 in study group and 3 in control group. Transmural injury was confirmed microscopically by the accumulation of acute inflammatory cells and loss of elastic fibers in the endocardium. In two pigs with failed conduction block, microscopic examination of the endocardium appeared normal. Conclusion: Failed radiofrequency ablation is strongly related to non-transmural energy delivery. The specially constructed compression device in the current study was successful in creating firm tissue-catheter contact and thereby generating transmural lesions during unipolar radiofrequency ablation.

• The Korean Journal of Medicine
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• v.99 no.1
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• pp.17-24
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• 2024

Premature atrial complex (PAC) and premature ventricular complex (PVC) are the most common arrhythmias. Most of them are benign, whereas some could be an initial sign of any underlying significant heart disease. Evaluation of daily burden and the presence of any association with underlying medical conditions are essential for proper assessment. Recently, newly developed electrocardiogram smart devices are widely available to document arrhythmias and identify correlations with symptoms. Management is required if the daily burden is high, patients are highly symptomatic, or significant structural heart disease is present. Antiarrhythmic drugs (AADs) are the first-line treatment, but if arrhythmias are drug-refractory or the patients are intolerable to AADs, catheter ablation is considered a good alternative in selected cases. In this paper, the proper diagnosis and management for PAC and PVC will be comprehensively reviewed.

• The Korean Journal of Nuclear Medicine
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• v.39 no.1
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• pp.9-14
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• 2005

Purpose: Abnormal myocardial perfusion may be caused by ventricular preexcitation, but its location, extent, severity and correlation with accessory pathway (AP) are not established. We evaluated perfusion patterns on myocardial perfusion SPECT and location of AP in patients with WPW (Wolff-Parkinson-White) syndrome. Materials and Methods: Adenosine Tc-99m MIBI or Tl-201 myocardial perfusion SPECT was performed in 11 patients with WPW syndrome. Perfusion defects (PD) were compared to AP location based on ECG with Fitzpatrick's algorithm or electrophysiologic study and radiofrequency catheter ablation. Results: Patients had atypical chest discomfort or no symptom. Risk of coronary artery disease (CAD) was below 0.1 in 11 patients using the nomogram to estimate the probability of CAD. Coronary angiography was performed in 4 patients (mid-LAD 50% in one, normal in others). In 4 patients, AP localization was done by electrophysiologic study and radiofrequency catheter ablation (RFCA). Small to large extent ($11.0{\pm}8.5%$, range:$3{\sim}35%$) and mild to moderate severity ($-71{\pm}42.7%$, range:$-2l7{\sim}-39%$) of reversible (n=9) or fixed (n=1) perfusion defects were noted. One patient with right free wall (right lateral) AP showed normal. PD locations were variable following the location of AP. One patient with left lateral wall AP was followed 6 weeks after RFCA and showed significantly decreased PD on SPECT with successful ablation. Conclusion: Myocardial perfusion defect showed variable extent, severity and location in patients with WPW syndrome. Abnormal perfusion defect showed in most of all patients, but it did not seem to be correlated specifically with location of accessory pathway and coronary artery disease. Therefore myocardial perfusion SPECT should be interpreted carefully in patients with WPW syndrome.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.7
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• pp.1417-1426
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• 2011

Radiofrequency ablation through cardiac catheterization is one of minimally invasive intervention procedures used in drug resistant arrhythmia treatment. To facilitate more accurate and precise catheter navigation, systems for robotic cardiac catheter navigation have been developed and commercialized. The authors have been developing a novel robotic catheter navigation system. The system is a network-based master-slave configuration 3-DOF (Degree-Of-Freedom) robotic manipulator for operation with conventional cardiac ablation catheter. The catheter manipulation motion is composed of the translation (forward/backward) and the roll movements of the catheter and knob rotation for the catheter tip articulation. The master manipulator comprises an operator handle compartment for the knob and the roll movement input, and a base platform for the translation movement input. The slave manipulator implements a robotic catheter platform in which conventional cardiac catheter is mounted and the 3-DOF motions of the catheter are controlled. The system software that runs on a realtime OS based PC, implements the master-slave motion synchronization control in the robot system. The master-slave motion synchronization performance tested with step, sinusoidal and arbitrarily varying motion commands showed satisfactory results with acceptable level of steady state error. The developed system will be further improved through evaluation of safety and performance in in vitro and in vivo tests.