Adult Dilated Cardiomyopathy Patient with Wolff-Parkinson-White Syndrome

We report on catheter ablation and clinical results in an adult with Wolff-Parkinson-White (WPW) syndrome for dyssynchrony-related dilated cardiomyopathy in the absence of supraventricular tachycardia (SVT). This patient did not have sustained SVT, but developed rapid progression of ventricular dysfunction that was not responsive to heart failure medication. Ventricular preexcitation could not be medically suppressed, but was successfully ablated. This was followed by complete resolution of ventricular dysfunction within six months.ope

All-in-One, Wireless, Stretchable Hybrid Electronics for Smart, Connected, and Ambulatory Physiological Monitoring

Commercially available health monitors rely on rigid electronic housing coupled with aggressive adhesives and conductive gels, causing discomfort and inducing skin damage. Also, research-level skin-wearable devices, while excelling in some aspects, fall short as concept-only presentations due to the fundamental challenges of active wireless communication and integration as a single device platform. Here, an all-in-one, wireless, stretchable hybrid electronics with key capabilities for real-time physiological monitoring, automatic detection of signal abnormality via deep-learning, and a long-range wireless connectivity (up to 15 m) is introduced. The strategic integration of thin-film electronic layers with hyperelastic elastomers allows the overall device to adhere and deform naturally with the human body while maintaining the functionalities of the on-board electronics. The stretchable electrodes with optimized structures for intimate skin contact are capable of generating clinical-grade electrocardiograms and accurate analysis of heart and respiratory rates while the motion sensor assesses physical activities. Implementation of convolutional neural networks for real-time physiological classifications demonstrates the feasibility of multifaceted analysis with a high clinical relevance. Finally, in vivo demonstrations with animals and human subjects in various scenarios reveal the versatility of the device as both a health monitor and a viable research tool.ope

A rat model of complete atrioventricular block recapitulates clinical indices of bradycardia and provides a platform to test disease-modifying therapies

Complete atrioventricular block (CAVB) is a life-threatening arrhythmia. A small animal model of chronic CAVB that properly reflects clinical indices of bradycardia would accelerate the understanding of disease progression and pathophysiology, and the development of therapeutic strategies. We sought to develop a surgical model of CAVB in adult rats, which could recapitulate structural remodeling and arrhythmogenicity expected in chronic CAVB. Upon right thoracotomy, we delivered electrosurgical energy subepicardially via a thin needle into the atrioventricular node (AVN) region of adult rats to create complete AV block. The chronic CAVB animals developed dilated and hypertrophied ventricles with preserved systolic functions due to compensatory hemodynamic remodeling. Ventricular tachyarrhythmias, which are difficult to induce in the healthy rodent heart, could be induced upon programmed electrical stimulation in chronic CAVB rats and worsened when combined with β-adrenergic stimulation. Focal somatic gene transfer of TBX18 to the left ventricular apex in the CAVB rats resulted in ectopic ventricular beats within days, achieving a de novo ventricular rate faster than the slow atrioventricular (AV) junctional escape rhythm observed in control CAVB animals. The model offers new opportunities to test therapeutic approaches to treat chronic and severe CAVB which have previously only been testable in large animal models.ope

Ar-Xe 혼합 플라즈마의 쉬스와 프리쉬스 사이에 형성된 전이영역에서 이온의 운동

학위논문 (석사)-- 서울대학교 대학원 : 에너지시스템공학부, 2013. 8. 김곤호.Ar-Xe 혼합기체 방전 플라즈마의 쉬스 내에서 각 이온종의 거동을 레이저유도형광(LIF) 진단을 통해 관찰하였다. 실험은 비자화된 약한 충돌성의 DC 필라멘트 방전 플라즈마에서 이루어졌다. 이온 분률 조건의 설정의 위해 단일종 필라멘트 방전 플라즈마의 입자균형방정식을 각 기체종에 도입하여 예측하였고, Hala[60]가 제안한 이온음파진단을 이용해 측정하여 검증하였다. 플라즈마 쉬스의 전위분포는 전자방출 정전탐침(EP)을 이용하여 측정하였다. 우선 단일종 플라즈마 쉬스의 전위분포를 Oksuz[19]의 분석법에 기초하여 해석함으로써, 쉬스의 전위구조를 쉬스-전이영역-프리쉬스의 삼중구조로 구분하였고, 각 영역의 길이와 전위차이를 측정하였다. 실험적으로 구분한 쉬스의 길이는 Child Law 모델이 예측하는 길이에 비하여 디바이 길이의 약 2배 정도 작고, 전이영역은 Riemann[18]의 예측에 비례하며, 프리쉬스는 이온-중성종간 평균 충돌자유행정거리에 비례함을 관찰하였다. 전이영역과 프리쉬스에서의 전위차이는 각각 1.4Te, 0.6Te 이었다. 이종 혼합기체 방전 플라즈마 쉬스의 전위분포를 해석하기 위해 Child Law 모델을 이종 이온이 존재하는 경우로 확장하였고, 이종 이온과 이종의 중성종간의 충돌경로를 고려한 유효 충돌자유행정거리를 도입하였다. 해석 결과, 이온 종의 분률과 상관없이 프리쉬스의 길이는 유효 충돌자유행정거리에 비례하나 전이영역의 길이는 이온이 혼합된 경우 단일 종의 경우보다 큰 값을 가짐을 관찰했다. 전위차이 또한 프리쉬스에서는 약 0.5Te로 일정하나, 전이영역에서는 이온이 혼합된 경우 단일 종의 경우보다 큰 값을 가짐을 관찰했다. 단일 이온종 LIF 이온유속 진단결과, 아르곤과 제논 두 경우 모두 실험적으로 구분된 플라즈마 쉬스 경계에서 디바이 길이의 약 2배 떨어진 지점, 즉 전이영역에서 Bohm 조건이 만족함을 확인하였다. 이 지점은 Child Law 모델로서 계산한 값과 동일한 지점이었다. 이종의 이온 쉬스에서의 LIF 이온유속 진단결과, 실험적으로 구분한 쉬스 경계에서 디바이 길이의 약 2배 떨어진 지점에서 각 이온의 속도가 Baalrud[11]가 제안한 instability 모델의 예측값과 일치하였다. 이는 기존의 선행연구[13]와 일치하는 결과였다. Instability가 발생함을 확증하고, 각 이온 종이 instability에 의하여 어느 공간에서 어떻게 속도가 형성되는지를 확인하기 위하여 각 이온의 상대속도 분포를 전위분포와 함께 비교하였다. 그 결과, 프리쉬스에서 상대속도가 증가하다가 전위영역에서 일정하게 유지됨과 그 크기는 Baalrud의 예측값과 오차범위 내에서 일치함을 최초로 확인하였다. 이로써 이종 기체 방전 플라즈마 쉬스에서 일반화된 Bohm 조건을 만족시키는 단일한 해를 예측하는 Baalrud의 instability 모델을 확증 할 수 있었다. 추가적으로, 단일종/이종 기체 방전 플라즈마 쉬스 구조상에서 Bohm 조건을 만족하는 지점이 모두 전이영역에 존재하게 된 이유에 대한 현상적인 해석을 진행함으로써, 이온-중성종간의 충돌이나 이온종간의 instability가 존재할 경우 Bohm 조건을 만족시키기 위한 전이영역의 역할에 대하여 논하였다.초 록 i 목 차 iii 표 목 차 v 그림목차 vi 제 1 장. 서 론 １ 제 2 장. 선행연구 ５ 2.1. 단일기체방전 플라즈마 쉬스의 전위구조 ５ 2.2. 단일기체 플라즈마 쉬스의 경계와 이온의 유동속도 １１ 2.3. 이종기체방전 플라즈마 쉬스와 일반화된 Bohm 조건 １３ 제 3 장. 실험장치 １９ 3.1. DC 필라멘트 방전 플라즈마 발생장치 １９ 3.2. 랭뮤어 정전탐침 (Langmuir ProbeLP) ２２ 3.3. 전자방출 정전탐침 (Emissive ProbeEP) ２５ 3.4. 레이저 유도 형광 진단 (Laser Induced FluorescenceLIF) ３１ 3.5. 이온 음파 진단(Ion Acoustic WaveIAW) ３８ 제 4 장. 이종기체 플라즈마 내 각 이온의 밀도 ４３ 4.1. 필라멘트 방전 플라즈마의 입자균형모델을 이용한 Ar-Xe 플라즈마 이온농도의 예측 ４４ 4.2. IAW를 이용한 Ar-Xe 플라즈마의 이온농도 진단 ４７ 제 5 장. 플라즈마 쉬스 전위 구조 ５１ 5.1. 단일 종 기체 방전 플라즈마의 쉬스 전위구조 ５１ 5.2. 이종 기체 방전 플라즈마의 쉬스 전위구조 ５７ 5.2.1. 이종 기체 방전 플라즈마 e-Free High Voltage 쉬스 ５７ 5.2.2. 이종 기체 방전 플라즈마 약한 충돌성 프리쉬스 모델 ５９ 5.2.3. Ar-Xe 이종 기체 방전 플라즈마의 쉬스 전위구조 ６２ 제 6 장. 플라즈마 쉬스 내 이온의 운동 ６７ 6.1. 단일 기체 방전 플라즈마 쉬스 내 이온의 운동 ６７ 6.2. 이종기체방전 플라즈마 쉬스 내 이온의 운동 ７０ 6.2.1. 이종기체방전 플라즈마 쉬스 경계에서 이온의 유동속도 ７０ 6.2.2. 이종기체방전 플라즈마의 쉬스구조 속 이온의 운동 ７３ 제 7 장. 결 론 ７７ 참고문헌 ８３ 부 록 ９１ A. Labview® 기반의 데이터 획득 프로그램과 데이터 수집 DAQ 회로의 구성 ９１ A.1. Labview® 기반의 데이터 획득 프로그램 ９１ A.2. 전자방출 정전탐침 구동회로 ９６ Abstract ９７Maste

Myocardial Tissue Doppler Velocity in Child Growth

Background: In adults, tissue Doppler imaging (TDI) is a recommended component of routine echocardiography. However, TDI velocities are less accepted in pediatrics, due to their strong variability and age dependence in children. This study examines the distribution of myocardial tissue Doppler velocities in healthy children to assess the effect of age with cardiac growth on the various echocardiographic measurements. Methods: Total 144 healthy children were enrolled in this study. They were recruited from the pediatric outpatient clinic for routine well-child visits. The statistical relationships between age and TDI values were analyzed. Also, the statistical relationships between body surface area (BSA) and TDI values, left ventricle end-diastolic dimension (LVEDD) and TDI values were analyzed. Also, we conducted multivariate analysis of cardiac growth parameters such as, age, BSA, LVEDD and TDI velocity data. Results: All of the age, BSA, and LVEDD had positive correlations with deceleration time (DT), pressure half-time (PHT), peak early diastolic myocardial velocity, peak systolic myocardial velocity, and had negative correlations with peak late diastolic velocity (A) and the ratio of trans-mitral inflow velocity to early diastolic velocity of mitral annulus (E/E'). In the multivariate analysis, all of the age, BSA, and LVEDD had positive correlations with DT, PHT, and negative correlations with A and E/E'. Conclusion: The cardiac growth parameters related alterations of E/E' may suggest that diastolic myocardial velocities are cardiac growth dependent, and diastolic function has positive correlation with cardiac growth in pediatric group. This cardiac growth related myocardial functional variation would be important for assessment of cardiac involvement either in healthy and sick child.ope

Conduit Puncture for Electrophysiological Procedures in Patients with Fontan Circulation

Background: Electrophysiological procedures are challenging in patients who have undergone lateral tunnel or extracardiac conduit Fontan operation because the caval veins are not connected to the cardiac atria and ventricles. This study describes our experience in managing a series of patients with Fontan circulation requiring catheter ablation for arrhythmias. Methods: This study included eight consecutive patients with Fontan circulation who underwent catheter ablation or pacemaker implantation via Fontan conduit puncture [median age (interquartile range), 21.5 (16.0-25.8) years; 5 men]. Lateral tunnel and extracardiac conduit were equally distributed among the eight patients. A standard technique for conduit puncture and subsequent electrophysiologic procedure was used. The time taken for conduit puncture was compared for different types of conduits. Results: The median age of patients in this series was 21.5 years (interquartile range: 16.0-25.8 years). Fontan conduit puncture via right femoral vein under intracardiac echocardiographic guidance was successfully performed without complications in seven of the eight patients. Conduit puncture failed in one patient with extracardiac conduit made of the pericardium due to interruption of both femoral veins. In three patients with Fontan conduit made of pericardium, a Bronckenbrough transseptal needle or a radiofrequency transseptal needle with a snare was used. In four patients with Fontan conduit made of Gore-tex, a radiofrequency transseptal needle with a snare, and percutaneous transluminal angioplasty balloon were used. Fontan conduit puncture time was significantly longer in patients with conduit made of Gore-tex (median time, 91 min; interquartile range, 59.8-130.5 min) than in patients with conduit made of the pericardium (median time, 11.5 min; interquartile range, 10.0-18.3 min), respectively (p=0.020). Conclusions: Conduit puncture is feasible and safe in patients with lateral tunnel and extracardiac Fontan circulation. Puncture of the Gore-tex conduit is more difficult and time consuming than puncture of the pericardium conduit.ope

Changes in Strain Pattern and Exercise Capacity after Transcatheter Closure of Atrial Septal Defects

Background and Objectives: Assessment of left ventricle (LV) function by using strain and strain rate is popular in the clinical setting. However, the use of these echocardiographic tools in assessing right ventricle (RV) failure, and the manner in which they both reflect the functional capacity of the patient, remains poorly understood. This study aimed to investigate the change in exercise capacity and strain between before and (1 month) after the transcatheter closure of atrial septal defects (ASDs). Subjects and Methods: Thirty patients who underwent transcatheter closure of ASD between May 2014 and June 2015 at the Division of Pediatric Cardiology, Severance Cardiovascular Hospital, were enrolled. We compared and analyzed the results of the following examinations, before and (1 month) after the procedure: echocardiography, cardiopulmonary exercise test (CPET), and N-terminal probrain natriuretic peptide level. Results: There were no mortalities, and the male-to-female ratio was 1:2. The mean defect size was 22.3±4.9 mm; the mean ratio of pulmonary to systemic flow, 2.1±0.5; and the mean device size, 22.3±4.9 mm. Changes in global RV longitudinal (GRVL) strain and LV torsion were measured echocardiographically. Exercise capacity improved from 7.7±1.2 to 8.7±1.8 metabolic equivalents (p=0.001). These findings correlated to the change in GRVL strain (p=0.03). Conclusion: The average exercise capacity increased after device closure of ASD. The change in strain was evident on echocardiography, especially for GRVL strain and LV torsion. Further studies comparing CPET and strain in various patients may show increased exercise capacity in patients with improved RV function.ope

In situ diagnosis and simultaneous treatment of cardiac diseases using a single-device platform

The in situ diagnosis of cardiac activities with simultaneous therapeutic electrical stimulation of the heart is key to preventing cardiac arrhythmia. Here, we present an unconventional single-device platform that enables in situ monitoring even in a wet condition and control of beating heart motions without interferences to the recording signal. This platform consists of the active-matrix array of pressure-sensitive transistors for detecting cardiac beatings, biocompatible, low-impedance electrodes for cardiac stimulations, and an alginate-based hydrogel adhesive for attaching this platform conformally to the epicardium. In contrast to conventional electrophysiological sensing using electrodes, the pressure-sensitive transistors measured mechanophysiological characteristics by monitoring the spatiotemporal distributions of cardiac pressures during heart beating motions. In vivo tests show mechanophysiological readings having good correlation with electrocardiography and negligible interference with the electrical artifacts caused during cardiac stimulations. This platform can therapeutically synchronize the rhythm of abnormal heartbeats through efficient pacing of cardiac arrhythmia.ope

The efficacy and safety of transcatheter closure of atrial septal defect with Amplatzer septal occluder in young children less than 3 years of age

Purpose : Applicability of transcatheter closure of atrial septal defect (ASD) has been expanded by accumulation of clinical experiences and evolutions of the device. This study was performed to evaluate the safety and efficacy of transcatheter closure of ASD with Amplatzer septal occluder (ASO) in young children less than 3 years of age. Methods : From May 2003 to December 2005, 295 patients underwent transcatheter closure of ASD with ASO in the Severance Cardiovascular Hospital, Yonsei University Health System. Among them, 51 patients less than 3 years of age were enrolled in this study. We investigated procedural success rate, rate of residual shunt, frequency of complications, procedure/fluoroscopy time, and need of modified techniques for device implantation. Results : the median age was 2.1 years and median body weight was 12 kg. Implantation of device was successful in 50 patients (98%). Seven patients (15%) showed a small residual shunt 1 day after the procedure, but complete occlusion had been documented at 6 month follow-up in all patients (100%). the pulmonary to systemic flow ratio (Qp/Qs), peak systolic pulmonary artery pressure, and peak systolic right ventricular pressure had decreased significantly after closure of ASD. There were 2 complications including device embolization (1, 2%) and temporary groin hematoma (1, 2%). Conclusion : Transcatheter closure of ASD with ASO can be performed with satisfactory results and acceptable risk even in young children less than 3 years of age. We could suggest that even in very young children with ASD, there is no need to wait until they grow to a sufficient size for the transcatheter closure.ope

The Comparison between the Echocardiographic Data to the Cardiac Catheterization Data on the Diagnosis, Treatment, and Follow-Up in Patients Diagnosed as Pulmonary Valve Stenosis

BACKGROUND: Isolated pulmonary valve stenosis (PS) makes up 6-9% of all congenital heart defects among children. The initial gold standard for diagnosis, follow-up of PS is by echocardiography. However, the most accurate diagnosis still remains to be measurement of the pressure gradient through transcatheterization. The purpose of this study is to compare the difference between the echocardiographic data to the cardiac catheterization data on the diagnosis, treatment, and follow-up in patients diagnosed as PS, and to see what parameters should be closely monitored. METHODS: A total of 112 patients (Male : Female = 46 : 66) who underwent balloon pulmonary valvuloplasty (BPV) at Severance Cardiovascular Hospital, between December, 2002 to August, 2012 were retrospectively analyzed. The patients were all under 16 years of age and critical PS patients who underwent BPV were excluded from this study. RESULTS: The pre-BPV right ventricle (RV)-pulmonary artery (PA) systolic pressure gradient and post-BPV systolic pressure gradient showed statistically significant decrease. The pre-BPV RV-PA systolic pressure gradient and 3 month post-BPV systolic pressure gradient showed statistically significant decrease. The consistency between the echocardiographic data and cardiac catheterization data shows statistically significant consistency. The mean pressure gradient and systolic pressure gradient on the echocardiography shows high consistency when comparing with the cardiac catheterization data. CONCLUSION: Our study shows that BPV in PS is a safe and effective procedure in children and adolescent. The standard echocardiographic evaluation of PS, during diagnosis and follow-up, should include mean transpulmonic pressure gradient, as well as the peak systolic pressure gradient. The success of the procedure should be held off until at least 3 months, only if the patients do not show any symptoms.ope