Optical Imaging of Embryonic Cardiac Conduction

Ma, Pei Case Western Reserve University ProQuest Dissertat 2016 해외박사(DDOD)

소속기관이 구독 중이 아닌 경우 오후 4시부터 익일 오전 9시까지 원문보기가 가능합니다.

Coordinated cardiac conduction plays an important role in cardiogenesis, not only for initiating rhythmic contractions of cardiac myocytes for efficient blood pumping, but also for maintaining normal cardiac development. Optical mapping (OM), which uses fluorescent voltage-sensitive dyes to measure membrane potential is currently the most effective method for electrophysiology studies in early embryonic hearts due to its noninvasiveness and large field-of-view. OM has two major limitations: 1) it projects signals from part of a 3D sample to a 2D map therefore the electrophysiological information is incomplete, orientation-dependent and ignorant of 3D topology of the sample; 2) it requires excitation-contraction (EC) uncoupling drugs to stop the contraction of the heart, yet EC-uncouplers may affect calcium handling, ion channel kinetics and action potential characteristics. This dissertation focuses on overcoming the limitations of OM and improving cardiac conduction imaging in embryonic hearts. First, OM was integrated with optical coherence tomography (OCT), which is capable of capturing the 3D topology of the looped embryonic heart. A 3D conduction velocity correction algorithm was developed. This eliminated underestimation bias in 2D conduction velocity calculation and provided more accurate 3D corrected conduction velocity measurements. Second, 4D OM in the embryonic heart was achieved with light-sheet fluorescence microscopy. We built a fast light-sheet system that illuminated the sample with a sheet of light generated by a cylindrical lens and collected OM signals from an orthogonal direction. OM data from multiple slices throughout the looping stage quail embryonic hearts were acquired. With this imaging system, complete, orientation independent, four-dimensional transmembrane potentials were demonstrated. Next, correction of motion artifacts in freely beating embryonic hearts was demonstrated using a B-spline nonrigid registration algorithm. Activation maps and conduction velocity measurements calculated from motion-corrected and the motion-free recordings are comparable. Finally, cardiac neural crest cells (CNCCs) were ablated in quail embryos as a congenital heart disease (CHD) model. Structural and functional defects at early and late stages were detected. This model will be applied in the investigation of how abnormalities in the conduction system arises. The imaging tools and CHD model developed here will significantly benefit the investigation of both normal and abnormal developmental cardiac electrophysiology.

유동가시화와 전산유동해석을 이용한 TCPC에서의 혈액유동특성

윤상호 연세대학교 대학원 2004 국내석사

하나의 심실이 체순환과 폐순환을 모두 담당하고 있기 때문에 TCPC에서 에너지 보존은 매우 중요하다. TCPC에서 에너지 손실은 TCPC 형상과 매우 밀접한 관계가 있으며, TCPC 형상(geometry)과 에너지 손실 또는 압력 손실의 관계에 대한 연구는 매우 중요하다. 본 연구에서는 선천적 심장질환을 가지고 태어나 TCPC 수술을 받은 환자에서의 혈류 역학적 연구를 위해 유동가시화와 전산유동해석의 두 가지 방법을 이용하였다. 자기공명영상으로부터 얻은 환자의 실제 이미지를 중요한 혈관요소만으로 재구성하였고, 재구성된 모델을 가지고 유동가시화 실험을 위한 유리모델과 전산유체해석을 위한 모델을 구성하였다. 상대정맥과 하대정맥을 통해 유입된 유동은 intra-atrial channel에서 서로 직접적으로 충돌을 일으키며, intra-atrial channel 내부를 순환하는 유동이 지배적으로 나타났다. 오른 폐동맥과 왼 폐동맥으로 흘러가는 유동에서는 소용돌이 유동이 지배적으로 나타난다. 이 유동은 전체유량에 오른 폐동맥과 왼 폐동맥의 비율이 50:50일 때 가장 작은 소용돌이 유동이 유동가시화와 전산유동해석 모두에서 관찰되었다. 또한 TCPC 모델 전체에 걸쳐 압력 손실과 에너지 손실을 계산해 보았다. 압력손실 결과를 살펴보면 intra-atrial channel과 폐동맥 분기점에서 거의 모든 압력손실이 발생하며, 오른 폐동맥에서의 압력손실이 왼 폐동맥에서의 압력손실 보다 크게 나타났다. 에너지 손실 면에서도 같은 결과를 볼 수 있었다. 상대정맥과 하대정맥이 서로 충돌하는 유동의 에너지 손실이 가장 크고 다음이 intra-atrial channel을 순환하는 유동, 그리고 대정맥을 통해 도관으로 직접 이동하는 유동에서 에너지 손실이 가장 작게 나타났다. 또한 에너지 손실의 거의 대부분은 intra-atrial channel에서 발생하였다. 본 연구를 통해서 다음과 같은 결론을 얻을 수 있었다. 1. 직접적인 유동의 충돌과 소용돌이 유동은 TCPC 모델에서 에너지 손실을 유발시키는 주요 요인이다. 2. 오른 폐동맥과 왼 폐동맥의 유량 비율이 50:50일 때 가장 작은 압력손실이 나타났으며, 오른 폐동맥과 왼 폐동맥의 유량이 균형을 이룰 때 에너지 보존이 가장 효율적이었다. 3. 큰 intra-atrial channel 공동이나 오른 폐동맥의 급격한 굴곡과 같은 TCPC 모델의 형상도 에너지 손실을 유발시키는 요인이며 이와 같은 부분이 제거 된다면 에너지 효율을 높일 수 있을 것으로 생각된다. Fontan operations are performed for congenital heart defects such as tricuspid atresia and univentricular heart. Energy conservation in TCPC procedure is very important, since there is a single functional ventricle to pump blood to both systemic and pulmonary circulations. The purpose of the present study was to determine hemodynamic characteristics in an anatomically correct TCPC model using flow visualizations and computational fluid dynamic (CFD) studies. From magnetic resonance (MR) images, a realistic glass model was fabricated to visualize steady flow. Total flow rates were 4, 6, 8ℓ/min and flow rates of SVC and IVC were 40% and 60% respectively. The flow split ratio between LPA and RPA was varied by 30:70, 40:60 and 50:50. Based on in vitro scaled model, computational fluid dynamic models were constructed. Inlet and outlet conditions were given as those in flow visualization studies. A pressure-based finite-volume software, CFD-ACE, was used to solve flow dynamics in TCPC models. Both flow visualizations and CFD studies were performed to determine hemodynamic characteristics in various TCPC models of Fontan surgeries. From the present study, the following conclusions were obtained. SVC and IVC flow were merged directly to the intra-atrial conduit. Significant swirl motion, especially in LPA and RPA, was also observed. Flow collision or swirl motion of flow resulted in fluid dynamic energy losses in TCPC models. It was also found that the RPA has a larger pressure loss than the LPA. Also, it was found that the large energy loss appeared intra-atrial channel and pulmonary bifurcation regions. A large chamber or a sharp bend in TCPC geometries might influence on energy losses.

The Structure and Utilization of Social Support Networks of Parents of Children With Congenital Heart Defects During Hospitalization

Mansfield, Kelly Jean The University of Utah ProQuest Dissertations & Th 2023 해외박사(DDOD)

소속기관이 구독 중이 아닌 경우 오후 4시부터 익일 오전 9시까지 원문보기가 가능합니다.

Parents of children with congenital heart defects (CHD) experience increased stress during their child's hospital admission for surgical repair. The experience of hospitalization leads to poor parent outcomes, including anxiety and depression. Social support can mitigate stress in parents of children with CHD. During hospitalization, parents are isolated from day-to-day networks and may rely on formal support (e.g., from hospital staff) to fill in support gaps. The extent to which this occurs is unclear. Therefore, understanding parents social support networks within the hospital will help ensure parents have appropriate access to support. The purpose of this study, guided by Pearlin's Stress Process Model, was to 1) describe social support networks of parents and the relationships between network characteristics, perception of support/stress, and mental health outcomes and 2) examine the function and role of parents' formal and informal networks. Twenty parents of children hospitalized for CHD repair were recruited from an intermountain west hospital. This mixed-methods study included an online survey assessing parents' social support networks, mental health, and perceptions of stress and support, along with a related semi-structured interview. Descriptive statistics were used to depict the structure of parents' social networks. Interview analysis used open and deductive coding to examine social network functioning. While social network characteristics, stress, and support were not associated with mental health outcomes, aspects of parent relationships could improve parental support. Relationship strength and availability were identified as key components of supportive networks. Parents relied on primary network members with whom they identify a strong relationship. Peripheral network members, such as distant family members and acquaintances, provided less support and could become a source of increased stress during the hospital stay. Support from formal sources such as hospital staff were contingent upon the relationship between parents and individual staff members.Parents need support from both formal and informal sources during hospitalization. Formal networks such as hospital staff and connections could fill gaps in support. Providing education to parents and hospital staff about social support needs and utilization could be a next step in improving parental outcomes. .

Influence of respiration on systemic venous and pulmonary arterial flow pattern after Fontan operation: Direct intravascular Doppler analysis

최재영 연세대학교 대학원 2012 국내박사

Background: The flow pattern and efficiency in the Fontan circuit vary according to the surgical modification of the Fontan operation. Sporadic studies have reported that cardiac and respiratory cycles have important influence on Fontan circulation, the details concerning the role of each component and/or interactions of respiration and heart beats according to surgical modification has been poorly appreciated. We assessed the flow patterns in the systemic veins and pulmonary artery during different respiratory and cardiac cycles by novel technique of direct intravascular Doppler assessment to evaluate the influence of heart beats, respiratory efforts and technical modifications on established Fontan circulation. Method: We surveyed 40 patients who had undergone a Fontan operation; 8 with an atriopulmonary connection (APC group), 22 with a total cavopulmonary connection with lateral tunnel (LTF group), and 10 with a total cavopulmonary connection with extracardiac conduit (ECF group). We used direct intravenous Doppler echocardiography with the Flowmap System (Medtronics, Minneapolis, MN, USA) and obtained Doppler measurements at the superior vena cava (SVC), inferior vena cava (IVC), hepatic vein (HV), left pulmonary artery (LPA) and Right pulmonary artery (RPA). We compared the average peak velocity (APV), velocity-time integral (VTI), net antegrade flow integral (NAFI), mean flow rate (MFR = Q), pulsatility index (PI), respiratory variability index (RVI) and inspiration/expiration MFR (IEQ) at each vessels among the three Fontan groups. The RVI and IEQ were also compared among vessels in each group. Results: On the comparison of VTI, APV and NAFI, the values in the ECF group showed tendency toward increase than those in the APC group, especially during inspiratory phase at the HV and both PAs (P<0.05) . However, in systolic phase during expiration, the VTI and APV at the HV were larger in APC group than other 2 groups (P<0.05). The PIs were significantly increased at all vessels in the APC group, regardless of the respiratory cycle (P < 0.05). The RVIs of APC group were significantly reduced at all vessels compared to those of other groups (P < 0.05). On comparison of RVIs among 5 vessels, the HV showed significantly increased RVIs in all 3 groups. Conclusion: Our findings provide integrated information concerning the influence of respiration and heart beats on the established Fontan circulation and its difference according to surgical modifications. Blood flow profiles shows superior efficiency in patients undergone ECF operation than in those with APC Fontan operation, and the flow efficiency is augmented during inspiratory phase. APC is associated with higher pulsatile flow mainly attributed to heart beats which pertains potential benefit of less endothelial dysfunction in long-term. Higher respiratory dependency of flow in the HV in all groups suggests the need of surveillance on their long-term effect on hepatic function and splanchnic circulation in post-Fontan patient.

신생아 심장 수술의 임상적 고찰

오기원 경북대학교 일반대학원 2007 국내석사

Purpose : The purpose of this study was to investigate the clinical features and outcome in newborns undergoing cardiac surgery. Methods : Eighty two neonates underwent heart surgery for congenital heart defect at Kyungpook national university hospital between March 2000 and February 2006. Patient characteristics(sex, age, diagnosis), operation type, postoperative complications and mortality were reviewed retrospectively. Results : In 82 patients, 41(50%) were male. The mean age and weight at operation were 12days and 3.2kg, respectively. The most common cardiac anomalies were complete transposition of the great arteries(TGA), Tetralogy of Fallot(TOF), pulmonary atresia with intact ventricular septum, and single ventricle variants. Fifty seven operations were performed with cardiopulmonary bypass and corrective surgery had done in 68%. Arterial switch operation and modified Blalock-Taussig shunt were most frequently performed as corrective and palliative operations, respectively. The early hospital mortality rate was 7% and late mortality was 3.9%. Common complications were acute renal insufficiency, delayed sternal closure, wound infection, arrhythmia, and brain hemorrhage. Conclusion : During recent 6 years, the outcomes of cardiac surgery for congenital heart defects in neonates improved by progress in perioperative, anaesthetic, surgical, and postoperative care. 목적 : 최근 선천성 심장병에 대한 다양한 분야의 발전이 거듭됨에 따라 신생아기의 수술 성적 또한 많은 향상을 보이고 있다. 이에 최근 6년 간 경북대학교 병원에서 신생아기에 수술을 받은 환아들의 임상적 특징 및 수술 성적에 대해 알아보고자 하였다. 방법 : 2000년 3월부터 2006년 2월까지 6년간 경북대학교 병원에서 신생아기에 수술을 받은 82명에 대해 이들의 수술 당시 나이 및 체중, 심기형의 종류, 수술 내용 및 결과, 합병증 등을 검토하였다. 결과 : 대상 환아 82명 중 남아는 41명이었으며 수술 당시 평균 나이는 12일, 평균 몸무게는 3200g이었다. 주된 심기형은 완전대혈관전위, 활로씨사징, 심실중격이 온전한 폐동맥판폐쇄, 기능적 단심실이 다수를 차지하였다. 수술 방법으로 인공심폐기를 사용한 경우가 57례였고, 54례(67%)에서 완전 교정수술을 시행하였다. 수술 종류로 완전 교정수술로는 동맥전환수술이, 고식 수술로는 변형 B-T 단락술이 가장 많이 시행되었다. 총 사망은 9례(10.9%)였으며 이 중 조기 사망은 6례, 만기 사망은 3례였다. 수술 후 주요 합병증은 급성 신기능 부전, 지연 흉골 봉합, 상처감염, 수술 후 부정맥, 뇌실내 또는 뇌내출혈 등이 발생하여 내과적 치료를 필요로 하였다. 결론 : 최근 6년간 본원에서 신생아기의 선천성 심장병에 대한 수술적 치료는 수술 전 처치, 수술 방법, 체외 순환법 그리고 수술 후 집중 치료의 발달을 통해서 많은 향상을 보였다.

Assessment of Fetal Cardiac Function via Magnetocardiography and Echocardiography

Phan, Tan The University of Wisconsin - Madison ProQuest Dis 2023 해외박사(DDOD)

소속기관이 구독 중이 아닌 경우 오후 4시부터 익일 오전 9시까지 원문보기가 가능합니다.

Postnatally, a comprehensive assessment of heart rhythm and function is obtained by recording electrocardiography and echocardiography simultaneously; however, prenatally this has not been possible due to the low quality signals produced by fetal ECG. Previous work by our group has simultaneously recorded fetal magnetocardiography (fMCG) and fetal echocardiography (fEcho) using a superconducting quantum interference device (SQUID) housed inside a magnetically-shielded room (MSR) and battery-operated ultra-sound scanner, respectively; however, the scanner inside the MSR introduced significant interference in the fMCG data. In this study we used a fMCG system based on an array of optically-pumped magnetometers housed within a person-sized magnetic shield. The new system improved the fMCG signal quality by shielding the OPMs from scanner interference.Simultaneous fMCG-fEcho were performed on a handful of healthy fetuses and those with arrhythmia. The P-wave, an important diagnostic feature, was clearly resolved in the fMCG signal. We were able to implement this technique to record real-time fMCG-fEcho. We also demonstrated that the valve clicks from fEcho images could be used to resolve QRS complexes in stretches of low-quality fMCG data, potentially allowing us to perform fMCG in fetuses in the first trimester.The magneto-mechanical parameters of fetuses with LQTS, those with a family history of LQTS but tested negative for LQTS (mutation-negative), and normal fetuses were also explored via fMCG and fEcho. The isovolumetric relaxation time (IVRT) was found to be a reliable predictor of the QT interval in the LQTS fetuses. The IVRT was prolonged in the LQTS and mutation-negative fetuses compared to the controls. QRS-T discordance was proposed as a contributing factor to IVRT prolongation due to a high rate of discordance in the LQTS and mutation-negative fetuses.The same parameters were assessed in fetuses with congenital heart defects (CHD). The IVRT was prolonged in the CHD fetuses but could not predict the QT interval. These fetuses also displayed a high rate of QRS-T discordance.Neither the magnetic nor mechanical parameters could independently characterize the fetal cardiac conditions examined in this project; however, new insights into the diseased conditions were provided by combining the magneto-mechanical parameters.

소아 심도자술 전·후 간호 하이브리드 시뮬레이션 교육프로그램 개발 및 효과

진은주 강원대학교 대학원 2023 국내박사

연구의 필요성: 우리나라 아동 인구는 지속적으로 감소하고 있으며 NICU와 소아과 병동의 환자 중증도는 상승하고 환자 안전과 권리 의식 증가로 간호학생은 학교에서 배운 지식과 술기를 임상 현장에서 적용하는 것에 어려움이 있다. 선천성 심장질환은 아동간호학에서 필수적으로 다루어지는 학습 내용이나 임상 현장에서 직접 경험하거나 실습 할 수 있는 기회는 제한적이므로 시뮬레이션 실습 교육을 통한 경험 제공이 필요하다. 특히 아동 간호에서는 보호자와의 협력적 관계를 위한 의사소통이 매우 중요하므로 표준화 환자를 활용한 부모와의 의사소통 훈련이 요구된다. 목적 : 고충실도 시뮬레이터와 표준화 환자를 동시에 활용한 하이브리드 시뮬레이션 실습 교육을 통한 실제 임상 사례를 기반으로 임상 현장을 재현한 소아 심도자술 전·후 간호 시나리오를 개발하고 지식, 임상수행 능력 자신감, 의사소통 자기효능감, 의사소통 능력, 교육프로그램 만족도를 파악하고자 한다. 연구 방법 : A-D-D-I-E 모형에 따라 시뮬레이션을 개발하고 시뮬레이션 실습 교육내용은 NLN/JSF(National League for Nursing/Jeffries Simulation Framework)을 근거로 구성하였다. 의사소통 능력 중 비언어적 의사소통 능력을 분석하기 위한 SMU Face/Pose Analysis Program을 개발하고 한국간호교육평가원 시뮬레이션 실습 표준안에 맞추어 시나리오를 개발하였다. 효과검증을 위해 무작위 할당 시차 설계를 적용한 유사 실험 연구를 진행하였다. 실험군 24명, 대조군 24명을 총 48명이 참여하였으며 중도 탈락은 없었다. 대조군에게는 전통적 이론강의를 시행하고 실험군에게는 전통적 이론강의와 하이브리드 시뮬레이션 교육프로그램을 제공하였다. 결과 : 2회기 10세션으로 구성된 소아 심도자술 전·후 간호 하이브리드 시뮬레이션 교육프로그램을 개발하고 적용하였다. SMU Face/Pose Analysis Program을 통해 분석된 결과를 비언어적 의사소통에 대한 피드백용으로 사용하였다. 교육프로그램 만족도는 10개 항목 중 9개 항목에서 ‘매우 그렇다’가 대부분을 차지하였으며, 지식(F=4.41, p=.017), 임상수행 능력 자신감(F=8.03, p=.001), 의사소통 자기효능감(F=3.90, p=.024)은 집단과 시점 간의 상호작용에 모두 유의한 차이를 보였다. 실험군의 의사소통 능력은 유의하게 상승하였다(t=3.32, p=.003). 결론 : 개발된 시뮬레이션 시나리오는 구현 가능하며 효과가 입증되었으므로 학교 교육 현장에서 제한된 임상 실습을 보완하는 교수법으로 활용 가능하다. The population of children in South Korea is continuously decreasing, and the severity of heath conditions of patients in neonatal intensive care unit (NICU) and pediatric ward is increasing; additionally, nursing students face difficulties in applying the knowledge and skills acquired in school to clinical practice because of increased awareness of patient safety and rights. Nursing of children with congenital heart disease is an essential part of pediatric nursing; however, as there is limited opportunity for nursing students to directly experience or practice such type of nursing, it is necessary to provide them this experience through simulation training. Regarding child health nursing, effective communication with parents/caregivers is highly important for establishing a cooperative relationship; therefore, providing nursing students with training for communication with parents/caregivers using standardized patients is necessary. Based on prior clinical cases, this study employs hybrid simulation practice education to develop nursing scenarios for pre and post pediatric catheterization by using high-fidelity simulators and standardized patients. These scenarios reproduced the clinical scene, subsequently testing students' knowledge, clinical performance confidence, communication self-efficacy, communication skills, and satisfaction with the developed educational program. The hybrid simulation program was developed according to the ADDIE model, and the contents of the simulation training were configured based on the NLN/JSF (National League for Nursing/Jeffries Simulation Framework). SMU Face/Pose Analysis Program was developed to analyze the non-verbal communication ability of nursing students, and scenarios were developed according to the simulation practice standards of the Korean Accreditation Board of Nursing Education. To verify the effect of the program, a quasi-experimental study using a random assignment design was conducted. In total, 48 participants (n=24 in the experimental group; n= 24 in the control group) participated in the study, and there was no dropout. While traditional theory lectures were provided to the control group, traditional theory lectures and a hybrid simulation education program were provided to the experimental group. A hybrid simulation education program for nursing pre and post pediatric catheterization consisting of two parts and 10 sessions was developed and applied. The results of the SMU Face/Pose Analysis Program were analyzed and used for assessing the participants’ feedback on non-verbal communication practice. Regarding the participants’ satisfaction with the hybrid simulation education program, the participants rated “very yes” for 9 out of 10 items; further, knowledge (F=4.41, p=.017), confidence in clinical performance (F=8.03, p=.001), and communication self-efficacy (F=3.90, p=.024) showed a significant difference in both groups and interaction between time points, and the communication ability of the experimental group increased significantly (t=3.32, p=.003). Thus, as the hybrid simulation program developed in this study has been proven effective, it can be implemented in nursing schools throughout South Korea, supplementing the limited clinical practice in nursing school education.

심장수술을 받은 환아 어머니-간호사 파트너십 프로그램 개발 및 효과 평가

엄주연 연세대학교 대학원 2017 국내박사

CATCH22 증후군에서 체세포 융합방법을 이용한 22번 염색체의 q11 미세결실 범위에 대한 연구

허준 서울대학교 대학원 2001 국내박사

Pulmonary artery size and late functional outcome after Fontan operaton

백재숙 서울대학교 대학원 2011 국내석사