• Journal of Biomedical Engineering Research
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• v.29 no.5
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• pp.343-347
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• 2008

Thermal conductivity, thermal diffusivity were measured in the atrium of a swine heart. Radiofrequency (RF) catheter ablation in an atrium has rapidly emerged at the treatment of symptomatic reentrant arrhythmia associated with accessory pathway or Atrioventricular (AV) node conduction. The thermal properties of an atrium are definitely necessary for these treatments because, in thermal treatments, conductivity and diffusivity are significant factors in the relationship between the applied RF power and the resulting atrium temperature rise. Thermal properties were measured using a self-heated thermistor probe. Thermistor probes were inserted into the tissue of interest and were used to supply heat within the tissue as well as to monitor the temperature rise in the tissue. The measurements were performed at temperatures of 25, 37, $50^{\circ}C$. Atrium thermal conductivity ranged from 5.17$\pm$0.12 mW/cm$^{\circ}C$ at $25^{\circ}C$ to 5.33$\pm$0.08 mW/cm$^{\circ}C$ at $37^{\circ}C$. Atrium thermal diffusivity ranged from 0.00132$\pm$0.00007$cm^2$/sec at $25^{\circ}C$ to 0.00138$\pm$0.00003 $cm^2$/sec at $50^{\circ}C$. This paper also present the thermal property comparison of both chambers of a heart (ventricle and atria).

• Journal of Chest Surgery
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• v.53 no.5
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• pp.270-276
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• 2020

Background: We investigated the impact of previous catheter ablation (CA) on the midterm outcomes of totally thoracoscopic ablation in patients with lone atrial fibrillation (AF). Methods: Between February 2012 and July 2018, 332 patients underwent totally thoracoscopic ablation for the treatment of AF (persistent AF; n=264, 80%). The patients were stratified into CA (n=47, 14%) and non-CA (nCA; n=285, 86%) groups according to their CA history. Results: All the baseline clinical characteristics and risk factors were similar between the groups except for age, percentage of male patients, prevalence of paroxysmal AF, prior percutaneous coronary intervention, and left atrial volume index (LAVI). No significant intergroup differences were observed in the incidence of early and late complications. At late follow-up, normal sinus rhythm was observed in 92% (43 of 47) of the patients in the CA group and 85% (242 of 285) of the patients in the nCA group (p=0.268). The rate of freedom from AF recurrence at 5 years was 55.3%±11.0% in the CA group, which was similar to that in the nCA group (55.7%±5.1%, p=0.690). In Cox regression analysis, preoperative brain natriuretic peptide levels and LAVI were associated with AF recurrence, but CA history was not significant. Conclusion: Totally thoracoscopic ablation was safe and effective in treating AF irrespective of CA history. A history of CA did not appear to affect the procedural complexity.

• 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 Pain
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• v.31 no.3
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• pp.215-220
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• 2018

Meralgia paresthetica (MP) is a sensory mononeuropathy, caused by compression of the lateral femoral cutaneous nerve (LFCN) of thigh. Patients refractory to conservative management are treated with various interventional procedures. We report the first use of extended duration (8 minutes) pulsed radiofrequency of the LFCN in a case series of five patients with refractory MP. Four patients had follow up for 1-2 years, and one had 6 months follow up. All patients reported remarkable and long lasting symptom relief and an increase in daily life activities. Three patients came off medications and two patients required minimal doses of neuropathic medications. No complications were observed.

• Journal of the Korean Society of Radiology
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• v.79 no.6
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• pp.323-331
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• 2018

Purpose: The purpose of this study was to evaluate the effectiveness of thoracic paravertebral block (TPVB) for management of pain during and after percutaneous radiofrequency ablation (RFA) of hepatic tumor. Materials and Methods: All patients were divided into non-TPVB (4 patients, 4 sessions of RFA for 4 tumors) and TPVB group (5 patients, 7 sessions of RFAs for 7 tumors). Ultrasound (US)-guided TPVB was performed at T7 level. The 15 mL of 0.375% ropivacaine was injected into right paravertebral space before RFA. If patients complained pain and asked analgesics or experienced pain with verbal numerical rating scale (VNRS) of more than 4, fentanyl $25{\mu}g$ (up to $100{\mu}g$), pethidine 25 mg, and midazolam 0.05 mg/kg (up to 5 mg) were sequentially given intravenously during RFA. Results: Total intravenous morphine equivalence of analgesics before, during, and after RFA was 129.1 mg and 0.0 mg in non-TPVB and TPVB group, respectively. Conclusion: US-guided TPVB may be an effective and safe anesthetic method for decreasing or eliminating pain during and after RFA for hepatic tumor and helpful in decreasing the usage of opioids.

• Tuberculosis and Respiratory Diseases
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• v.72 no.2
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• pp.228-231
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• 2012

Bronchobiliary fistula (BBF), defined as an abnormal communication between the biliary duct and bronchial trees, is a very rare condition. Bilioptysis is a pathognomonic finding for BBF. We studied a 58-year-old man, who had a BBF complicated by liver biloma that occurred after radiofrequency ablation. The diagnosis was confirmed by the presence of bile-stained sputum and an Endoscopic Retrograde Cholangio-Pancreatography. BBF was treated successfully by endoscopic sphincterotomy and biliary drainage with insertion of a double pig-tail plastic stent into the biloma. We suggest that the optimal choice of treatment modality for BBF depends on the natural course of the underlying disease, and the status of the biliary stricture.

• 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.

• Clinical and Experimental Pediatrics
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• v.54 no.12
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• pp.507-511
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• 2011

Purpose: The aim of the present study was to evaluate the characteristics of electrophysiologic studies (EPS) and radiofrequency ablation (RFA) performed in subjects aged less than 30 years with Wolff-Parkinson-White (WPW) syndrome, particularly pediatric patients under 18 years of age, based on our experience. Methods: Two hundred and one consecutive patients with WPW syndrome were recruited and divided to 3 groups according to age: group 1, 6 to 17 years; group 2, 18 to 29 years; and group 3, 30 to 60 years. The clinical, electrophysiological, and therapeutic data for these patients were evaluated by a retrospective medical record review. Results: A total of 73 (36%) of these patients were <30 years of age. Although there were more males than females in group 2 (male:female, 31:11), there was no sex difference in group 1 (male:female, 16:15). Left accessory pathway was detected less frequently in group 1 (32%, 10/31) than in group 2 (57%, 24/42) and group 3 (63%, 81/128) (P=0.023 and P=0.002, respectively). Conclusion: The present study describes several different electrophysiological characteristics in children and adolescents with WPW syndrome. Therefore, when EPS and RFA are performed in children and adolescence with WPW syndrome, we recommend that these characteristics be considered.

• The Korean Journal of Pain
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• v.30 no.4
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• pp.296-303
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• 2017

Background: To achieve a prolonged therapeutic effect in patients with lumbar facet joint syndrome, radiofrequency medial branch neurotomy (RF-MB) is commonly performed. The purpose of this study was to evaluate the prognostic value of paravertebral muscle twitching when performing RF-MB in patients with lumbar facet joint syndrome. Methods: We collected and analyzed data from 68 patients with confirmed facet joint syndrome. Sensory stimulation was performed at 50 Hz with a 0.5 V cut-off value. Patients were divided into 3 groups according to the twitching of the paravertebral muscle during 2 Hz motor stimulation: 'Complete', when twitching was observed at all needles; 'Partial', when twitching was present at 1 or 2 needles; and 'None', when no twitching was observed. The relationship between the long-term effects of RF-MB and paravertebral muscle twitching was analyzed. Results: The mean effect duration of RF-MB was 4.6, 5.8, and 7.0 months in the None, Partial, and Complete groups, respectively (P = 0.47). Although the mean effect duration of RF-MB did not increase significantly in proportion to the paravertebral muscle twitching, the Complete group had prolonged effect duration (> 6 months) than the None group in subgroup analysis. (P = 0.03). Conclusions: Paravertebral muscle twitching while performing lumbar RF-MB may be a reliable predictor of long-term efficacy when sensory provocation under 0.5 V is achieved. However, further investigation may be necessary for clarifying its clinical significance.

• Journal of Chest Surgery
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• v.51 no.2
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• pp.146-148
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• 2018

Left atrial appendage (LAA) aneurysm is a rare, pathologic condition that may lead to atrial tachyarrhythmia or thromboembolic events. A 49-year-old man presented with aggravated palpitation and dizziness. He suffered from refractory atrial fibrillation despite a previous history of radiofrequency catheter ablation. Echocardiography revealed a 57-mm LAA aneurysm. Surgical ablation was performed through a right mini-thoracotomy, and the LAA aneurysm was obliterated with a 50-mm AtriClip (Atricure Inc., Westchester, OH, USA). However, follow-up computed tomography showed residual communication, so the patient is still taking warfarin. We report that a minimally invasive strategy for treating LAA aneurysm can be considered, but incomplete closure may occur; thus, caution is needed.