The Usefulness of a Simplified Navigation-Based Instrumentation for a Novice Surgeon in Primary Total Knee Arthroplasty: A Retrospective Analysis of a Randomized Controlled Trial

Background@#A novel simplified navigation-based instrumentation system has been developed. It simplifies the existing navigation system and facilitates convenient bone cutting by positioning the tracker on an existing cutting block without additional pin fixation. This study aimed to compare the outcomes of this newly developed simplified navigation-based instrumentation system in primary total knee arthroplasty (TKA) performed by a novice surgeon with those of conventional surgical techniques. @*Methods@#From January 2020 to July 2020, 67 knees that underwent primary TKA using the ExactechGPS TKA Plus (group A) were compared to 68 knees that underwent primary TKA using a conventional technique (group B). All patients had a minimum follow-up of 24 months. The operative details such as tourniquet time were investigated. Postoperative hip-knee-ankle (HKA) angle and component position angles in the coronal and sagittal planes (α, β, γ, and δ angles) were evaluated. The outlier rates were compared between the groups as those lying outside ± 3°. Knee Injury and Osteoarthritis Outcome Score for Joint Replacement, the Western Ontario and McMaster Universities Osteoarthritis Index for pain and function, and range of motion were compared. @*Results@#There was no statistically significant difference in average tourniquet time between the groups (74.3 vs. 70.3 minutes, p = 0.061). Outlier rates for HKA angle (7.5% vs. 23.5%, p = 0.010) and β angle (1.5% vs. 22.1%, p < 0.001) in group A were significantly lower than those in group B. There were no significant differences in clinical outcomes between the groups. @*Conclusions@#Primary TKA performed by a novice surgeon using a simplified navigation-based instrumentation system did not significantly increase the operation time, and more accurate lower extremity mechanical alignment and tibial component alignment in the coronal plane could be obtained.

Long-term Outcome of Fontan-Associated Protein-Losing Enteropathy: Treatment Modality and Predictive Factor of Mortality

Background and Objectives@#Protein-losing enteropathy (PLE) is a devastating complication after the Fontan operation. This study aimed to investigate the clinical characteristics, treatment response, and outcomes of Fontan-associated PLE. @*Methods@#We reviewed the medical records of 38 patients with Fontan-associated PLE from 1992 to 2018 in 2 institutions in Korea. @*Results@#PLE occurred in 4.6% of the total 832 patients after the Fontan operation. After a mean period of 7.7 years after Fontan operation, PLE was diagnosed at a mean age of 11.6years. The mean follow-up period was 8.9 years. The survival rates were 81.6% at 5 years and 76.5% at 10 years. In the multivariate analysis, New York Heart Association Functional classification III or IV (p=0.002), low aortic oxygen saturation (<90%) (p=0.003), and ventricular dysfunction (p=0.032) at the time of PLE diagnosis were found as predictors of mortality. PLE was resolved in 10 of the 38 patients after treatment. Among medical managements, an initial heparin response was associated with survival (p=0.043). Heparin treatment resulted in resolution in 4 patients. We found no evidence on pulmonary vasodilator therapy alone. PLE was also resolved after surgical Fontan fenestration (2/6), aortopulmonary collateral ligation (1/1), and transplantation (1/1). @*Conclusions@#The survival rate of patients with Fontan-associated PLE has improved with the advancement of conservative care. Although there is no definitive method, some treatments led to the resolution of PLE in one-fourth of the patients. Further investigations are needed to develop the best prevention and therapeutic strategies for PLE.

Association between the Use of Diuretics and Size Reduction in Pediatric Atrial Septal Defect

Background and Objectives@#While diuretics are sometimes used in atrial septal defect (ASD) treatment, their effect on ASD size reduction remains unclear. We aimed to evaluate the efficacy of diuretics in ASD size reduction in pediatric patients. @*Methods@#We retrospectively reviewed the medical records of patients with secundum ASD (size ≥10 mm), between 2005 and 2019. Patients were divided into two groups based on the diuretic administration. @*Results@#Of the 73 enrolled patients, 40 received diuretics. The initial age at ASD diagnosis (2.8±1.7 vs. 2.5±2.0 years, p=0.526) and follow-up duration (22.3±11.4 vs. 18.7±13.2 months, p=0.224) were not significantly different between the groups. The ASD diameter at the initial diagnosis (13.7±2.0 vs. 13.5±3.4 mm, p=0.761) and the indexed ASD diameter (25.5±5.9 vs. 26.9±10.3 mm/m2 , p=0.493) were also not significantly different between two groups. The ASD diameter significantly increased in the non-diuretic group during follow-up (0.0±2.9 vs. +2.6±2.0 mm, p<0.001). The indexed ASD diameter significantly decreased in the diuretic group during follow-up (−5.7±6.5 vs. +0.2±3.9 mm/m 2 , p<0.001). In the linear mixed model analysis, diuretic use was associated with ASD diameter decrease (p<0.001) and indexed ASD diameter reduction (p<0.001) over time. Device closure was more frequently performed in the diuretic (75.0%) than in the non-diuretic group (39.4%). @*Conclusions@#Patients receiving diuretics are less likely to undergo surgery. The diuretics administration may be associated with the use of smaller ASD devices for transcatheter treatment through ASD size reduction.

The impact of novel COVID-19 initial pandemic on orthopedic healthcare: an experience from a single institution of South Korea

Background@#This study was to investigate the cancellation rate and trend of orthopedic surgeries during the novel coronavirus disease 2019 (COVID-19) pandemic. Moreover, we assessed the psychologic status of orthopedic healthcare workers, and investigated the details of the preventive surgeries underwent in COVID-19-positive patients. @*Methods@#For 3 months after January 20, 2020, cancellation rates of elective surgeries were investigated, and the number of elective surgeries conducted in the same period over the last two years was compared. Four different questionnaires were used to investigate psychologic status among the orthopedic health care workers. We compared the outcomes according to occupation (physician or nurse), and type of work (faculty staff or resident physician). Outcomes according to occupation and type of work were compared. Preventive surgeries underwent in patients who could not wait for the results of the COVID-19 diagnosis were investigated. @*Results@#Spine and hip surgery had relatively lower cancellation rates, and elective surgeries were significantly reduced. During the initial pandemic, the cancellation rate of orthopedic elective surgeries was significantly higher than in the same period of the previous year and was different for each subdivision depending on the degree of pain or disability. The psychological outcomes were within the normal range and there were no significant differences between groups. After preventive surgery, all medical staff involved in the operation tested negative. @*Conclusion@#During the COVID-19 pandemic, the cancellation rate of orthopedic elective surgeries was significantly higher than in the same period of the previous year. Orthopedic health care workers did not seem to have significant psychological distress. As a result of the preventive surgery in specialized facilities, all the medical staff who participated in the operation tested negative.

The Waiting List Mortality of Pediatric Heart Transplantation Candidates in Korea before the Pediatric Ventricular Assist Device Era

Background@#Despite advancements in heart transplantation for pediatric patients in Korea, the waiting list mortality has not been reported. Therefore, we investigated the waiting list mortality rate and factors associated with patient mortality. @*Methods@#We reviewed the medical records of pediatric patients who were registered for heart transplantation at three major hospitals in Korea from January 2000 to January 2020.All patients who died while waiting for heart transplantation were investigated, and we identified the waiting list mortality rate, causes of mortality and the median survival periods depending on the variable risk factors. @*Results@#A total of 145 patients received heart transplantations at the three institutions we surveyed, and the waiting list mortality rate was 26%. The most common underlying diseases were cardiomyopathy (66.7%) and congenital heart disease (30.3%). The leading causes that contributed to death were heart failure (36.3%), multi-organ failure (27.2%), and complications associated with extracorporeal membrane oxygenation (ECMO) (25.7%). The median survival period was 63 days. ECMO was applied in 30 patients. The different waiting list mortality percentages according to age, cardiac diagnosis, use of ECMO, and initial Korean Network of Organ Sharing (KONOS) level were determined using univariate analysis, but age was the only significant factor associated with waiting list mortality based on a multivariate analysis. @*Conclusion@#The waiting list mortality of pediatric heart transplantation candidates was confirmed to be considerably high, and age, underlying disease, the application of ECMO, and the initial KONOS level were the factors that influenced the survival period.

Identification of rare coding variants associated with Kawasaki disease by whole exome sequencing

Kawasaki disease (KD) is an acute pediatric vasculitis that affects genetically susceptible infants and children. To identify coding variants that influence susceptibility to KD, we conducted whole exome sequencing of 159 patients with KD and 902 controls, and performed a replication study in an independent 586 cases and 732 controls. We identified five rare coding variants in five genes (FCRLA, PTGER4, IL17F, CARD11, and SIGLEC10) associated with KD (odds ratio [OR], 1.18–4.41; p = 0.0027–0.031). We also performed association analysis in 26 KD patients with coronary artery aneurysms (CAAs; diameter > 5 mm) and 124 patients without CAAs (diameter < 3 mm), and identified another five rare coding variants in five genes (FGFR4, IL31RA, FNDC1, MMP8, and FOXN1), which may be associated with CAA (OR, 3.89–37.3; p = 0.0058–0.0261). These results provide insights into new candidate genes and genetic variants potentially involved in the development of KD and CAA.

IgA Levels Are Associated with Coronary Artery Lesions in Kawasaki Disease

Background and Objectives@#Kawasaki disease (KD) is an acute systemic vasculitis that affects the coronary arteries. Abnormal immune reactions are thought to contribute to disease pathogenesis. The effect of immunoglobulin (Ig) isotype (IgG, IgA, IgM, and IgE) on inflammatory data and clinical outcomes of patients with KD was examined. @*Methods@#Ig levels in 241 patients with KD were measured during the acute, subacute, convalescent, and normal phases of the disease. @*Results@#Compared with reference Ig values, IgG, IgA, and IgM levels were significantly higher in the subacute phase, while IgE levels were elevated in 73.9% (178/241) of patients with KD in all clinical phases. However, high IgE levels were not associated with clinical outcomes, including intravenous immunoglobulin unresponsiveness and coronary artery lesions (CALs).Significantly more CALs were observed in the high IgA group than in the normal IgA group (44.7% vs. 20.8%, respectively; p<0.01). In addition, IgA levels in the acute phase (p=0.038) were 2.2-fold higher, and those in the subacute phase were 1.7-fold higher (p <0.001), in the CAL group than in the non-CAL group. IgA concentrations increased along with the size of the coronary artery aneurysm (p <0.001). Furthermore, there was a strong correlation between IgA levels and CAL size (r=0.435, p<0.001), with a high odds ratio of 2.58 (p=0.022). @*Conclusions@#High IgA levels in patients with KD are prognostic for the risk of CALs.

Effect of Pulmonary Valve Replacement in the Repaired Tetralogy of Fallot Patients with Trans-annular Incision:More than 20 Years of Follow-up

Background and Objectives@#We reviewed the long-term outcomes after tetralogy of Fallot (TOF) repair with trans-annular incision; and evaluated the effectiveness of pulmonary valve replacement (PVR) on outcomes. @*Methods@#This was a retrospective review of clinical outcomes of 180 of 196 TOF patients who underwent total correction with trans-annular incision from 1991 to 1997 (PVR group: 81; non-PVR group: 99). @*Results@#The median age of the patients was 14.0 months (interquartile range [IQR], 10.7–19.8 months) at TOF repair. Ten in-hospital deaths (5.1%) occurred. During the followup, 81 patients underwent PVR at the median age of 13.5 years (IQR, 11.2–17.1 years). The patients in PVR group showed better outcomes than non-PVR group in overall survival rate (100% in PVR vs. 88.7% in non-PVR, p=0.007), in all adverse events (arrhythmia, neurologic complications, 95.5% in PVR vs. 74.6% in non-PVR, p=0.024) at 20 years. Age at TOF repair younger than 1 year (hazard ratio [HR], 2.265; p=0.01) and previous shunt history (HR, 2.195; p=0.008) were predictive for requiring PVR. During follow-up, 10 late deaths (5 sudden deaths) occurred in the non-PVR group, mainly due to ventricular arrhythmia and right ventricular failure; there was 1 late death (not a sudden death) in the PVR group. @*Conclusions@#Long-term survival after repair of TOF with trans-annular incision were acceptable. However, arrhythmias were frequently observed during 20 years of follow-up. The patient age <1 year at the time of TOF repair and shunt implantation prior to TOF repair were predictive factors for requiring PVR.

Epidemiology and Clinical Features of Myocarditis/Pericarditis before the Introduction of mRNA COVID-19 Vaccine in Korean Children:a Multicenter Study

Background@#Korean health authority plans to vaccinate adolescents against coronavirus disease 2019 (COVID-19) starting high school seniors during the summer vacation of 2021.However, the myocarditis/pericarditis following COVID-19 vaccine has been reported recently in adolescents and young adults. This study was performed to answer the urgent questions about the basic epidemiology and clinical course of myocarditis/pericarditis in hospitalized patients prior to the introduction of COVID-19 vaccines in pediatric population. @*Methods@#A retrospective medical record analysis including frequency, clinical characteristics, etiology and outcome of myocarditis/pericarditis was conducted in 17 years and younger patients who were hospitalized in two referral hospitals in Korea between 2010 and 2019. @*Results@#Total 142 patients with myocarditis (n = 119) and/or pericarditis (n = 23) were identified. Median age was 5.4 years (interquartile range, 0.6–12.9 years; range, 11 days–17.8 years), and male was 61%. In adolescents aged 12–17 years, the male to female ratio was 3.2. Myocarditis/pericarditis occurred 0.70 per 1,000 in-patients during the study period: 0.96 (< 1 year), 0.50 (1–5 years), 0.67 (6–11 years) and 1.22 (12–17 years) per 1,000 in-patients, respectively. There was an increasing tendency for the annual frequency from 0.34 in 2010 to 1.25 per 1,000 in-patients in 2019 (P = 0.021). Among the 56 (40%) proven pathogens at admission, Mycoplasma pneumoniae (n = 11, 8%) and enterovirus (n = 10, 7%) were most common. Of the 142 patients, 99 (70%) required pediatric intensive care unit care and 10 (7%) received heart transplantation. In addition, 61 patients (61/131, 47%) without heart medication at admission needed heart medication when they were discharged. Eleven (7.7%) patients died, of which five patients were previously healthy. The median age of deceased patients was lower than the survival group (0.8 vs. 6.3 years, P = 0.014). @*Conclusion@#The frequency of myocarditis/pericarditis was highest among male adolescent in-patients; however, the outcome was favorable in this group without any mortality.

IgA Levels Are Associated with Coronary Artery Lesions in Kawasaki Disease

Background and Objectives@#Kawasaki disease (KD) is an acute systemic vasculitis that affects the coronary arteries. Abnormal immune reactions are thought to contribute to disease pathogenesis. The effect of immunoglobulin (Ig) isotype (IgG, IgA, IgM, and IgE) on inflammatory data and clinical outcomes of patients with KD was examined. @*Methods@#Ig levels in 241 patients with KD were measured during the acute, subacute, convalescent, and normal phases of the disease. @*Results@#Compared with reference Ig values, IgG, IgA, and IgM levels were significantly higher in the subacute phase, while IgE levels were elevated in 73.9% (178/241) of patients with KD in all clinical phases. However, high IgE levels were not associated with clinical outcomes, including intravenous immunoglobulin unresponsiveness and coronary artery lesions (CALs).Significantly more CALs were observed in the high IgA group than in the normal IgA group (44.7% vs. 20.8%, respectively; p<0.01). In addition, IgA levels in the acute phase (p=0.038) were 2.2-fold higher, and those in the subacute phase were 1.7-fold higher (p <0.001), in the CAL group than in the non-CAL group. IgA concentrations increased along with the size of the coronary artery aneurysm (p <0.001). Furthermore, there was a strong correlation between IgA levels and CAL size (r=0.435, p<0.001), with a high odds ratio of 2.58 (p=0.022). @*Conclusions@#High IgA levels in patients with KD are prognostic for the risk of CALs.

Effect of Pulmonary Valve Replacement in the Repaired Tetralogy of Fallot Patients with Trans-annular Incision:More than 20 Years of Follow-up

Background and Objectives@#We reviewed the long-term outcomes after tetralogy of Fallot (TOF) repair with trans-annular incision; and evaluated the effectiveness of pulmonary valve replacement (PVR) on outcomes. @*Methods@#This was a retrospective review of clinical outcomes of 180 of 196 TOF patients who underwent total correction with trans-annular incision from 1991 to 1997 (PVR group: 81; non-PVR group: 99). @*Results@#The median age of the patients was 14.0 months (interquartile range [IQR], 10.7–19.8 months) at TOF repair. Ten in-hospital deaths (5.1%) occurred. During the followup, 81 patients underwent PVR at the median age of 13.5 years (IQR, 11.2–17.1 years). The patients in PVR group showed better outcomes than non-PVR group in overall survival rate (100% in PVR vs. 88.7% in non-PVR, p=0.007), in all adverse events (arrhythmia, neurologic complications, 95.5% in PVR vs. 74.6% in non-PVR, p=0.024) at 20 years. Age at TOF repair younger than 1 year (hazard ratio [HR], 2.265; p=0.01) and previous shunt history (HR, 2.195; p=0.008) were predictive for requiring PVR. During follow-up, 10 late deaths (5 sudden deaths) occurred in the non-PVR group, mainly due to ventricular arrhythmia and right ventricular failure; there was 1 late death (not a sudden death) in the PVR group. @*Conclusions@#Long-term survival after repair of TOF with trans-annular incision were acceptable. However, arrhythmias were frequently observed during 20 years of follow-up. The patient age <1 year at the time of TOF repair and shunt implantation prior to TOF repair were predictive factors for requiring PVR.

Epidemiology and Clinical Features of Myocarditis/Pericarditis before the Introduction of mRNA COVID-19 Vaccine in Korean Children:a Multicenter Study

Background@#Korean health authority plans to vaccinate adolescents against coronavirus disease 2019 (COVID-19) starting high school seniors during the summer vacation of 2021.However, the myocarditis/pericarditis following COVID-19 vaccine has been reported recently in adolescents and young adults. This study was performed to answer the urgent questions about the basic epidemiology and clinical course of myocarditis/pericarditis in hospitalized patients prior to the introduction of COVID-19 vaccines in pediatric population. @*Methods@#A retrospective medical record analysis including frequency, clinical characteristics, etiology and outcome of myocarditis/pericarditis was conducted in 17 years and younger patients who were hospitalized in two referral hospitals in Korea between 2010 and 2019. @*Results@#Total 142 patients with myocarditis (n = 119) and/or pericarditis (n = 23) were identified. Median age was 5.4 years (interquartile range, 0.6–12.9 years; range, 11 days–17.8 years), and male was 61%. In adolescents aged 12–17 years, the male to female ratio was 3.2. Myocarditis/pericarditis occurred 0.70 per 1,000 in-patients during the study period: 0.96 (< 1 year), 0.50 (1–5 years), 0.67 (6–11 years) and 1.22 (12–17 years) per 1,000 in-patients, respectively. There was an increasing tendency for the annual frequency from 0.34 in 2010 to 1.25 per 1,000 in-patients in 2019 (P = 0.021). Among the 56 (40%) proven pathogens at admission, Mycoplasma pneumoniae (n = 11, 8%) and enterovirus (n = 10, 7%) were most common. Of the 142 patients, 99 (70%) required pediatric intensive care unit care and 10 (7%) received heart transplantation. In addition, 61 patients (61/131, 47%) without heart medication at admission needed heart medication when they were discharged. Eleven (7.7%) patients died, of which five patients were previously healthy. The median age of deceased patients was lower than the survival group (0.8 vs. 6.3 years, P = 0.014). @*Conclusion@#The frequency of myocarditis/pericarditis was highest among male adolescent in-patients; however, the outcome was favorable in this group without any mortality.

Current perspectives in stem cell therapies for osteoarthritis of the knee / 영남의대학술지

Mesenchymal stem cells (MSCs) are emerging as an attractive option for osteoarthritis (OA) of the knee joint, due to their marked disease-modifying ability and chondrogenic potential. MSCs can be isolated from various organ tissues, such as bone marrow, adipose tissue, synovium, umbilical cord blood, and articular cartilage with similar phenotypic characteristics but different proliferation and differentiation potentials. They can be differentiated into a variety of connective tissues such as bone, adipose tissue, cartilage, intervertebral discs, ligaments, and muscles. Although several studies have reported on the clinical efficacy of MSCs in knee OA, the results lack consistency. Furthermore, there is no consensus regarding the proper cell dosage and application method to achieve the optimal effect of stem cells. Therefore, the purpose of this study is to review the characteristics of various type of stem cells in knee OA, especially MSCs. Moreover, we summarize the clinical issues faced during the application of MSCs.

A Case of Consumptive Hypothyroidism in a 1-Month-Old Boy with Diffuse Infantile Hepatic Hemangiomas

Consumptive hypothyroidism is a rare paraneoplastic syndrome characterized by excessive inactivation of the thyroid hormones due to increased type 3 iodothyronine deiodinase activity of tumors. We report the case of severe consumptive hypothyroidism in a 1-month-old boy with infantile hepatic hemangiomas who presented with cardiac failure and cholestasis. Diffuse infiltration of hepatic hemangiomas was detected on abdominal imaging studies, and thyroid function screening test revealed severe hypothyroidism, which necessitated the administration of higher-than-usual doses of levothyroxine for the normalization of thyroid function. The patient was successfully treated with propranolol, prednisolone, and levothyroxine, and he showed normal thyroid function at 3 months of age and normal neurodevelopment at 9 months of age. This case highlights the importance of early recognition and prompt management of consumptive hypothyroidism in patients with infantile hepatic hemangiomas.

End-of-Life Care of Hospitalized Children with Advanced Heart Disease

Background@#Despite improvements in palliative care for critically ill children, the characteristics of end-of-life care for pediatric patients with advanced heart disease are not well-known. We investigated these characteristics among hospitalized children with advanced heart disease in a tertiary referral center in Korea. @*Methods@#We retrospectively reviewed the records of 136 patients with advanced heart disease who died in our pediatric department from January 2006 through December 2013. @*Results@#The median age of patients at death was 10.0 months (range 1 day–28.3 years). The median duration of the final hospitalization was 16.5 days (range 1–690 days). Most patients (94.1%) died in the intensive care unit and had received mechanical ventilation (89.7%) and inotropic agents (91.2%) within 24 hours of death. The parents of 74 patients (54.4%) had an end-of-life care discussion with their physician, and the length of stay of these patients in the intensive care unit and in hospital was longer. Of the 90 patients who had been hospitalized for 7 days or more, the parents of 54 patients (60%) had a documented end-of-life care discussion. The time interval from the end-of-life care discussion to death was 3 days or less for 25 patients. @*Conclusion@#Children dying of advanced heart disease receive intensive treatment at the end of life. Discussions regarding end-of-life issues are often postponed until immediately prior to death. A pediatric palliative care program must be implemented to improve the quality of death in pediatric patients with heart disease.

Impending Cardiac Tamponade and Hemorrhagic Pleural Effusion as Initial Presentations of Incomplete Kawasaki Disease: A Case Report

Kawasaki disease (KD) is an acute febrile illness that is characterized by systemic inflammation usually involving medium-sized arteries and multiple organs during the acute febrile phase, leading to associated clinical findings. The diagnosis is based on the principal clinical findings including fever, extremity changes, rash, conjunctivitis, oral changes, and cervical lymphadenopathy. However, KD diagnosis is sometimes overlooked or delayed because other systemic organ manifestations may predominate in acute phase of KD. As a cardiovascular manifestation, an acute pericarditis usually shows a small pericardial effusion, but large pericardial effusion showing clinical signs of cardiac tamponade is very rare. Here, we described a case of incomplete KD presenting with impending cardiac tamponade, and recurrent fever and pleural effusion.

A Case of Lyme Disease Complicated with Atrioventricular Block in a 13-year-old Boy

Lyme disease is a common vector-borne disease caused by Borrelia burgdorferi. Erythema migrans represents the most common manifestation during the early phase of this disease;however, systemic manifestations involving the nervous system, joints, or heart are known to occur. We report a case of Lyme disease accompanied by cardiac complications in a 13-year-old Korean male adolescent. The patient developed annular erythematous lesions on his lower extremities after a field trip during his visit to Connecticut, USA, for a boarding school camp, and his skin lesions were consistent with erythema migrans. Indirect immunofluorescence assay and Western blot analysis for Lyme immunoglobulin M showed positive results. Electrocardiography revealed a first-degree atrioventricular block, and he was diagnosed with Lyme carditis and received a 4-week course of oral doxycycline. Follow-up electrocardiography performed a week later revealed normal findings, and the patient showed an uneventful recovery. Lyme carditis often presents as an asymptomatic heart block that can progress to an advanced heart block; however, this condition is reversible with appropriate antibiotic treatment.

Radiofrequency catheter ablation of ventricular tachycardia in pediatric patients

Background@#Radiofrequency catheter ablation (RFCA) has been accepted as an efficient therapy for tachycardia, and substantial improvement in the outcomes of RFCA in pediatric patients has been seen. However, there is not enough data on the clinical outcomes of RFCA for ventricular tachycardia (VT) in pediatric patients. The objective of this study was to elucidate the efficacy and safety of RFCA for VT in pediatric patients. @*Methods@#We performed a retrospective study involving 35 consecutive pediatric VT ablation procedures in 28 patients at a single institution. @*Results@#The median age at ablation was 14.0 years (range 6.9–19.2 years). There were 24 patients with a structurally normal heart and four patients with congenital heart disease (CHD). The left ventricular posteroseptal area was the most common site of VT origin (22/28, 78.6%). However, there was an unusual case of VT which involved a papillary muscle as its origin. Acute success was achieved in 30 (85.7%) of 35 procedures. The recurrence rate after successful RFCA was 14.2% (5/35) at a median follow-up of 6.7 years (range 1.0–16.7 years). There were five procedural failures due to the inability to induce VT for complete mapping. Ultimately, long-term success was achieved in 27 patients (96.4%) after repeated procedures and no major complications occurred. Long-term success was associated with VT inducibility (p = < 0.001). @*Conclusions@#Difficulty in inducing VT for precise mapping was a significant obstacle to successful RFCA. RFCA was identified as safe and effective therapy to eliminate VT in the selected pediatric VT patients.

A Case of Lyme Disease Complicated with Atrioventricular Block in a 13-year-old Boy

Lyme disease is a common vector-borne disease caused by Borrelia burgdorferi. Erythema migrans represents the most common manifestation during the early phase of this disease;however, systemic manifestations involving the nervous system, joints, or heart are known to occur. We report a case of Lyme disease accompanied by cardiac complications in a 13-year-old Korean male adolescent. The patient developed annular erythematous lesions on his lower extremities after a field trip during his visit to Connecticut, USA, for a boarding school camp, and his skin lesions were consistent with erythema migrans. Indirect immunofluorescence assay and Western blot analysis for Lyme immunoglobulin M showed positive results. Electrocardiography revealed a first-degree atrioventricular block, and he was diagnosed with Lyme carditis and received a 4-week course of oral doxycycline. Follow-up electrocardiography performed a week later revealed normal findings, and the patient showed an uneventful recovery. Lyme carditis often presents as an asymptomatic heart block that can progress to an advanced heart block; however, this condition is reversible with appropriate antibiotic treatment.

Radiofrequency catheter ablation of ventricular tachycardia in pediatric patients

Background@#Radiofrequency catheter ablation (RFCA) has been accepted as an efficient therapy for tachycardia, and substantial improvement in the outcomes of RFCA in pediatric patients has been seen. However, there is not enough data on the clinical outcomes of RFCA for ventricular tachycardia (VT) in pediatric patients. The objective of this study was to elucidate the efficacy and safety of RFCA for VT in pediatric patients. @*Methods@#We performed a retrospective study involving 35 consecutive pediatric VT ablation procedures in 28 patients at a single institution. @*Results@#The median age at ablation was 14.0 years (range 6.9–19.2 years). There were 24 patients with a structurally normal heart and four patients with congenital heart disease (CHD). The left ventricular posteroseptal area was the most common site of VT origin (22/28, 78.6%). However, there was an unusual case of VT which involved a papillary muscle as its origin. Acute success was achieved in 30 (85.7%) of 35 procedures. The recurrence rate after successful RFCA was 14.2% (5/35) at a median follow-up of 6.7 years (range 1.0–16.7 years). There were five procedural failures due to the inability to induce VT for complete mapping. Ultimately, long-term success was achieved in 27 patients (96.4%) after repeated procedures and no major complications occurred. Long-term success was associated with VT inducibility (p = < 0.001). @*Conclusions@#Difficulty in inducing VT for precise mapping was a significant obstacle to successful RFCA. RFCA was identified as safe and effective therapy to eliminate VT in the selected pediatric VT patients.