Background: Children with complex congenital heart disease (CHD) are exposed to cyanosis from birth until their surgical repair and are often not expected to participate in physical activities to the same extent as healthy peers because of a limited maximal exercise capacity (V̇O2max). Despite limitations in V̇O2max, these children may still have the capacity to perform most daily physical activity because it requires only a submaximal effort. The purpose of this research was to examine the relationships between submaximal exercise capacity, daily physical activity and cyanosis exposure, in children with complex CHD. Methods: Children with a single functioning ventricle (Fontan), tetralogy of Fallot or transposition of the great arteries, 10 to 17 years old were deemed eligible. The Bruce treadmill protocol with breath-by-breath analysis of oxygen consumption was used to assess submaximal exercise capacity. Five measures of submaximal exercise capacity were evaluated: energy consumption (V̇O2) at the ventilatory threshold, V̇O2 at a heart rate of 130 beats per minute (bpm), metabolic equivalents (METs) at ventilatory threshold, METs at 130 bpm and heart rate at stage 1 of the Bruce protocol. Moderate-to vigorous physical activity (MVPA) was measured (Actical accelerometer with 15 second epochs) for 7 consecutive days. Exposure to cyanosis was calculated by subtracting the child’s date of birth from the date of surgical repair. Results: Participants were children with a Fontan single ventricle (n=5), tetralogy of Fallot (n=4) or transposition of the great arteries (n=7). Daily physical activity was positively associated with V̇O2 at ventilatory threshold (r = 0.78, n = 16, p = < 0.01) and V̇O2 at a heart rate of 130 bpm (r = 0.61, n = 16, p = 0.01). Children who did more than 60 minutes of physical activity per day (n=4) achieved significantly higher energy expenditure before reaching ventilatory threshold, (95% CI of the difference [8.23, 24.85], t(14) = 4.27, p = < 0.01) and at a heart rate of 130 bpm (95% CI of the difference [1.61, 14.33], t(14) = 2.69, p = 0.02). Lastly, V̇O2 at ventilatory threshold was negatively associated with days spent in cyanosis (r = .55, n = 16, p = 0.03), Conclusion: Higher V̇O2 at ventilatory threshold and V̇O2 at a heart rate of 130 bpm was associated with more daily minutes spent in moderate-to-vigorous physical activity. These results suggest that children who meet the recommended 60 minutes of MVPA would have a higher submaximal exercise capacity (V̇O2 at ventilatory threshold or a heart rate of 130 bpm), than children who did not meet the MVPA guidelines. Lastly, children who were exposed to cyanosis for a longer period of time had a lower submaximal V̇O2 at ventilatory threshold, than children who were exposed to cyanosis for a shorter period of time.

Contexte : La dextro-transposition des gros vaisseaux et la transposition congénitalement corrigée des gros vaisseaux sont des cardiopathies congénitales où le ventricule de morphologie droite est en position sous-aortique (VDs) ou systémique et le ventricule de morphologie gauche est en position sous-pulmonaire donc avec une physiologie biventriculaire. Chez les patients avec un VDs, la capacité maximale à l’effort cardiorespiratoire (CMC) est réduite pour une multitude de facteurs, dont une unique artère coronaire alimentant le VDs en oxygène, une incapacité d’augmenter le volume d’éjection systolique, et/ou une demande accrue en oxygène du VDs hypertrophié menant ultimement à l’ischémie à l’effort. Des études antérieures suggèrent que la CMC est diminuée chez les patients avec un VDs comparativement à celle des individus sains avec un ventricule de morphologie gauche en position sous-aortique (VGs). Aucune étude à ce jour n’a tenté d’apparier des patients avec un VDs à des patients avec un VGs pour les paramètres cliniques tels que la classe fonctionnelle de la NYHA, la fonction systolique similaire du ventricule systémique et la médication. Méthodes : Une étude transversale rétrospective a été réalisée en appariant 24 adultes avec un VDs à 24 adultes avec un VGs pour le sexe, l’âge, l’indice de masse corporelle, la fraction d’éjection du ventricule systémique (normal, légère, modérée, sévère), la classe NYHA (I, II, III) et la prise de diurétiques. La consommation d’oxygène pic (V̇O₂pic), le pourcentage prédit de la V̇O₂pic (% V̇O₂pic) et la pente ventilation/dioxyde de carbone (pente V̇E/V̇CO₂) ont été comparés à un test de Wilcoxon signé-rang. Une sous-analyse a été faite en dichotomisant les groupes selon le critère de Weber selon la CMC (VGs V̇O₂pic > OU ≤ 20 mL/kg/min). Résultats : Un total de 18/24 (75%) patients avaient une classe fonctionnelle NYHA II-III et 23 (96 %) présentaient une dysfonction de leur VDs avec une haute incidence de traitement pour l’insuffisance cardiaque. Contrairement à la littérature antérieure, la V̇O₂pic (VDs: 20.1 ± 4.4 vs. VGs: 20.2 ± 4.8 mL∙ kg-1 ∙ min-1, p=0.966, d=n/a), % V̇O₂pic (63 ± 16 vs 69±17 % p=0.207, d=0.35) et la pente V̇E/V̇CO₂ (29 ± 6 vs 30 ± 6 % p=0.422, d= n/a) ne différaient pas entre les groupes. Après dichotomisation, la V̇O₂pic était plus basse chez les VDs comparativement aux VGs avec une CMC optimale. À l’inverse, la V̇O₂pic était supérieure chez les VDs comparativement aux VGs dont la CMC étaient sous-optimale. Le % V̇O₂pic démontrait un patron similaire, alors que la pente V̇E/V̇CO₂ ne différait pas entre les deux sous-groupes. Conclusion: Pour des patients avec VDs et VGs à circulation biventriculaire appariée pour des caractéristiques cliniques similaire et démontrant un phénotype d’insuffisance cardiaque, aucune différence significative n’était présente au niveau de la CMC. Une analyse plus approfondie suggère la présence de mécanismes physiologiques spécifiques au type de ventricule en position systémique. / Background: Dextro transposition of the great arteries or congenitally corrected transposition of the great arteries are congenital cardiopathies where the morphological right ventricle is in the sub-aortic position (sRV) or systemic and the morphological left ventricle is in the sub-pulmonary position (sRV), thus in bi-ventricular circulation. Cardiorespiratory fitness (CRF) in those patients is reduced by multiple factors including a unique coronary artery, the incapacity to increase stroke volume, and/or an acute oxygen demand caused by the hypertrophied sRV leading ultimately to ischemia. Past studies suggested that CRF is diminished in patients with sRV compared to healthy patients with sLV. No study to date has attempted to match patients with sRV to patients with slV for clinicals parameters as NYHA functional classification, similar function of the systemic ventricle, and medication. Methods: A retrospective cross-sectional study was performed by matching 24 adults with a sRV to 24 adults with a sLV matched for sex, age, body mass index, ejection fraction of the systemic ventricle (normal, mild, moderate, severe), NYHA class (I, II, III), and doses of diuretics. Peak oxygen consumption (V̇O₂peak), percentage predicted of V̇O₂peak (% V̇O₂peak), and ventilation/carbon dioxide production slope (V̇E/V̇CO₂ slope) were compared with a Wilcoxon signed-rank test. A sub-analysis was made by dichotomizing groups according to Weber’s criterion for CRF (sLV V̇O₂peak > OR ≤ 20 mL/kg/min). Results: A total of 18/24 (75%) matched paired were classified as NYHA functional class II-III and 23 (96%) presented a systemic ventricle dysfunction with higher incidence of heart failure treatment. V̇O₂peak (sRV: 20.1 ± 4.4 vs. sLV: 20.2 ± 4.8 mL/kg/min, p=0.966, d=n/a), % V̇O₂peak (63±16 vs 69±17 % p=0.207, d=0.35) and V̇E/V̇CO₂ slope (29±6 vs 30±6 % p=0.422, d= n/a) did not differ between groups. After dichotomization, V̇O₂peak was lower in sRV in those with optimal CRF. Oppositely, V̇O₂peak was greater in sRV in those with suboptimal CRF. The % V̇O₂peak displayed similar patterns, whereas V̇E/V̇CO₂ slope did not differ between sub-groups. 6 Conclusion: No significant differences in CRF were reported when comparing sRV and sLV biventricular physiology after matching the clinical characteristics within a cohort with heart failure phenotype but detailed analyses suggest specific physiological adaptive mechanisms.

Background: The transposition of the great arteries (TGA) is a common congenital heart disease. In the 1980s the Senning procedure was the major approach in correction of TGA in the Czech Republic. Although the most recent operation technique called arterial switch is the method of first choice nowadays, patients after Senning procedure are still visiting the cardiology centre. The aim of this thesis was to evaluate the relationship between the selected parameters from the exercise test and quantified level of physical activity (PA) in these individuals. Methods: 71 patients after the Senning procedure underwent a cardiopulmonary exercise test and they completed an international physical activity questionnaire (IPAQ). Selected data from the questionnaire and the exercise test were evaluated by Pearson correlation coefficient (p < 0,05). Results: 56 patients meet criteria of IPAQ (71 % male, n = 40) and were included in the study. Total PA averaged 6576 ± 5204 MET-minutes/week (median 5271 MET-minutes/week) and 70 % individuals meet criteria for high level of PA according to IPAQ data. Peak VO2 averaged 31,9 ± 6,6 ml/min/kg, maximum heart rate was 177 ± 18,6 beats per minute, the highest work load was 2,7 ± 0,8 W/kg and systolic blood pressure was 185 ± 24,0 mmHg. We found statistically significant...

A transposição das grandes artérias (TGA) é uma das mais comuns e importantes cardiopatias congênitas, apresenta-se de forma cianótica, incidindo entre 0,2 a 0,4 por 1000 nascidos vivos. A TGA é caracterizada anatomicamente por discordância ventrículo-arterial. O diagnóstico preciso e urgente é de fundamental importância para a escolha do tratamento e para evitar o descondicionamento dos ventrículos. O tratamento dessa anomalia é cirúrgico, cirurgia de Jatene, realizada pela primeira vez em 1975. Atualmente, os pacientes em pós operatório de cirurgia de Jatene passaram a ter garantia de uma melhor qualidade de vida e uma melhor sobrevida, porém com complicações operatórias tardias aparecem em cerca de 10 a 20% dos casos. A obstrução coronariana, uma das complicações operatórias tardias, determina risco de vida e sua incidência é variável. Vários métodos podem ser empregados para o diagnóstico de obstrução coronariana nestes pacientes. A angiotomografia cardíaca (angioTC) tem se mostrado um método não invasivo acurado para a detecção de doença coronariana obstrutiva. Outro método de avaliação é o teste cardiopulmonar (TCP), configurando-se uma ferramenta importante que mostra o comportamento de todo o sistema cardíaco durante o exercício físico. O objetivo deste trabalho é relacionar as alterações anatômicas diagnosticadas na angioTC com alterações fisiológicas do ecocardiograma (ECO) e do TCP para o diagnóstico de obstrução coronariana no paciente em pós-operatório tardio de cirurgia de Jatene. Assim foram incluídos na casuística 61 pacientes em pós operatório tardio de cirurgia de Jatene com idade igual ou superior a cinco anos. Avaliou-se aspectos gerais (identificação, gênero, idade), diagnóstico da cardiopatia, tratamento estabelecido e evolução clínica, por meio da análise dos prontuários. Os pacientes foram submetidos ao ECO, eletrocardiograma, radiografia de tórax, TCP e angioTC afim de avaliar a capacidade funcional e anatomia coronariana. Os principais resultados evidenciam que somente 3,3% dos pacientes foram diagnosticados como portadores de estenose coronariana por meio da angioTC e que estes pacientes eram assintomáticos e não apresentaram sinais de isquemia do miocárdio nos outros exames realizados. / Transposition of the great arteries (TGA) is a frequent cyanotic congenital heart disease, affecting about 0.3 per 1000 live births. TGA is anatomically characterized by ventriculoarterial discordance. The treatment for this anomaly is achieved through a surgical procedure, the arterial switch operation (ASO), performed for the first time in 1975. Patients in the postoperative period of Jatene\'s surgery are expected to have good quality of life, but late postoperative complications may arise in up to 20% of the cases. Coronary obstruction, determines risk of death and has a variable incidence. Several methods can be used for the diagnostic of coronary obstruction in these patients. Cardiac angiotomography has proven to be an accurate noninvasive method for the detection of obstructive coronary disease. The cardiopulmonary test, which may detect some issues due to cardiac stress, may also be performed. The objective of this study is to correlate anatomical changes diagnosed by cardic angiotomography with physiological alterations of the echocardiogram and the cardiopulmonar test for the diagnosis of coronary obstruction in the patient in the late postoperative period of ASO. We recruited 61 patients aged five years old and up who underwent ASO at our institution. General aspects (identification, gender, age), preoperatory diagnosis, and clinical evolution were evaluated by analyzing the medical records. The patients were submitted to ecocardiogram, electrocardiogram, chest X-ray, cardiopulmonar test and cardic angiotomography to evaluate functional capacity and coronary anatomy. The main results show that only 3.3% of the patients were diagnosed as having coronary stenosis by cardiac angiotomography, and that these patients were asymptomatic and showed no signs of myocardial ischemia in other examinations.

A transposição das grandes artérias (TGA) é uma das mais comuns e importantes cardiopatias congênitas, apresenta-se de forma cianótica, incidindo entre 0,2 a 0,4 por 1000 nascidos vivos. A TGA é caracterizada anatomicamente por discordância ventrículo-arterial. O diagnóstico preciso e urgente é de fundamental importância para a escolha do tratamento e para evitar o descondicionamento dos ventrículos. O tratamento dessa anomalia é cirúrgico, cirurgia de Jatene, realizada pela primeira vez em 1975. Atualmente, os pacientes em pós operatório de cirurgia de Jatene passaram a ter garantia de uma melhor qualidade de vida e uma melhor sobrevida, porém com complicações operatórias tardias aparecem em cerca de 10 a 20% dos casos. A obstrução coronariana, uma das complicações operatórias tardias, determina risco de vida e sua incidência é variável. Vários métodos podem ser empregados para o diagnóstico de obstrução coronariana nestes pacientes. A angiotomografia cardíaca (angioTC) tem se mostrado um método não invasivo acurado para a detecção de doença coronariana obstrutiva. Outro método de avaliação é o teste cardiopulmonar (TCP), configurando-se uma ferramenta importante que mostra o comportamento de todo o sistema cardíaco durante o exercício físico. O objetivo deste trabalho é relacionar as alterações anatômicas diagnosticadas na angioTC com alterações fisiológicas do ecocardiograma (ECO) e do TCP para o diagnóstico de obstrução coronariana no paciente em pós-operatório tardio de cirurgia de Jatene. Assim foram incluídos na casuística 61 pacientes em pós operatório tardio de cirurgia de Jatene com idade igual ou superior a cinco anos. Avaliou-se aspectos gerais (identificação, gênero, idade), diagnóstico da cardiopatia, tratamento estabelecido e evolução clínica, por meio da análise dos prontuários. Os pacientes foram submetidos ao ECO, eletrocardiograma, radiografia de tórax, TCP e angioTC afim de avaliar a capacidade funcional e anatomia coronariana. Os principais resultados evidenciam que somente 3,3% dos pacientes foram diagnosticados como portadores de estenose coronariana por meio da angioTC e que estes pacientes eram assintomáticos e não apresentaram sinais de isquemia do miocárdio nos outros exames realizados. / Transposition of the great arteries (TGA) is a frequent cyanotic congenital heart disease, affecting about 0.3 per 1000 live births. TGA is anatomically characterized by ventriculoarterial discordance. The treatment for this anomaly is achieved through a surgical procedure, the arterial switch operation (ASO), performed for the first time in 1975. Patients in the postoperative period of Jatene\'s surgery are expected to have good quality of life, but late postoperative complications may arise in up to 20% of the cases. Coronary obstruction, determines risk of death and has a variable incidence. Several methods can be used for the diagnostic of coronary obstruction in these patients. Cardiac angiotomography has proven to be an accurate noninvasive method for the detection of obstructive coronary disease. The cardiopulmonary test, which may detect some issues due to cardiac stress, may also be performed. The objective of this study is to correlate anatomical changes diagnosed by cardic angiotomography with physiological alterations of the echocardiogram and the cardiopulmonar test for the diagnosis of coronary obstruction in the patient in the late postoperative period of ASO. We recruited 61 patients aged five years old and up who underwent ASO at our institution. General aspects (identification, gender, age), preoperatory diagnosis, and clinical evolution were evaluated by analyzing the medical records. The patients were submitted to ecocardiogram, electrocardiogram, chest X-ray, cardiopulmonar test and cardic angiotomography to evaluate functional capacity and coronary anatomy. The main results show that only 3.3% of the patients were diagnosed as having coronary stenosis by cardiac angiotomography, and that these patients were asymptomatic and showed no signs of myocardial ischemia in other examinations.

Les cardiopathies congénitales cyanogènes (CCC) sont des malformations cardiaques qui entraînent une désaturation en oxygène à la naissance. Des progrès majeurs réalisés ces vingt dernières années dans la prise en charge médico-chirurgicale des nouveau-nés atteints de CCC ont permis de considérablement améliorer la survie et le pronostic cardiaque à long terme de cette population. Cependant, ces enfants sont exposés à un risque accru d’accidents neurologiques dû au caractère cyanogène de la cardiopathie et à certaines techniques de chirurgie à cœur ouvert. En conséquence, les troubles neurocognitifs font partie des principales morbidités résiduelles. Malgré l’augmentation exponentielle du nombre de patients qui atteignent dorénavant l’âge adulte, à ce jour très peu d’études ont investigué le devenir neuropsychologique des adultes opérés de CCC. Cette thèse a pour objectif principal d’évaluer le devenir neuropsychologique et psychosocial d’adultes ayant été opérés à cœur ouvert en période néonatale pour corriger une CCC. L’évaluation, qui repose sur des outils validés, est menée auprès de 67 patients âgés de 18 à 31 ans. Les résultats mettent en évidence qu’une proportion substantielle de patients présente des troubles cognitifs et émotionnels susceptibles de réduire leur qualité de vie et d’entraver leur réussite scolaire et leur insertion professionnelle. Ce travail offre des résultats pionniers concernant le devenir à long terme de cette population. D'autres études sont nécessaires pour mieux comprendre la trajectoire développementale des adultes opérés de CCC afin de mettre en place des stratégies préventives et thérapeutiques adaptées aux besoins de cette population. / Cyanotic congenital heart diseases (CHD) are heart defects which cause oxygen desaturation at birth. In the last twenty years, the major progress in the medical and surgical care of newborns with cyanotic CHD has resulted in a considerable improvement of the survival and the long-term cardiac prognosis of this population. However, these children are at an increased risk of neurological injuries due not only to the cyanotic nature of their CHD but also to certain open-heart surgery techniques. Consequently, neurocognitive disorders are among the major remaining morbidities in this population. Despite the exponential increase in the number of patients who can now reach adulthood, to date very few studies have investigated the neuropsychological outcomes of adults with cyanotic CHD. The main objective of the present thesis is to evaluate the neuropsychological and psychosocial outcomes of adults who had undergone an open-heart surgery during the neonatal period in order to correct a cyanotic CHD. The assessment, based on validated tools, is conducted among 67 patients aged from 18 to 31 years. The results show that a substantial proportion of patients with TGA presents a number of cognitive deficits and emotional impairments which may reduce their quality of life and hinder their academic success and their professional integration. This thesis offers original results on the long-term neuropsychological and psychosocial outcomes of this population. Further studies are needed so as to better understand the developmental trajectory of adults with cyanotic CHD in order to develop preventive and therapeutic strategies adapted to the specific needs of this population.

Le nombre d'adultes porteurs de cardiopathies congénitales, de plus en plus sévères est constante progression. A moyen voire long terme certain d’entre eux posent des problèmes d’insuffisance cardiaque et de troubles du rythme parfois létaux. La physiologie de ces complications est multi factorielle et s’écarte souvent des schémas habituels. L’asynchronisme ventriculaire présentent chez un nombre important d’entre eux est connu pour favoriser un remodelage ventriculaire conduisant à l’insuffisance cardiaque sur cœur sain.Dans ce travail en couplant données expérimentales animales et études cliniques, nous avons étudié : 1) l’impact aigu puis chronique de la resynchronisation biventriculaire sur un modèle animal d’insuffisance cardiaque droite mimant la tétralogie de Fallot et sur une population de patients ; 2) le rôle et la conséquence d’une stimulation conventionnelle sur une physiologie de ventricule droit systémique ; 3) l’effet délétère de la stimulation VD prolongée sur un modèle de cœur animal en cours de développement.Nous avons appris que 1) la resynchronisation biventriculaire permet un bénéfice hémodynamique significatif chez l’animal mais aussi sur une population de Fallot implantées ; 2) que l’asynchronisme généré par la stimulation conventionnelle est délétère pour la fonction du ventricule systémique mais aussi pour le cœur de l’enfant en cours développement. La resynchronisation est un traitement prometteur pour traiter l’insuffisance cardiaque mais pourrait aussi l’être pour en prévenir sa survenue. De nouvelles techniques d’implantation nous permettent aujourd’hui d’implanter des patients qui présentent beaucoup d’obstacles anatomiques et d’éviter nombre de complications grave de la stimulation. / The number of adults with severe congenital heart disease is constantly growing. At medium to long-term follow up, these patients may present with heart failure or conduction disorders, which may lead to death. The pathophysiology and clinical course of these complications is multi-factorial and may be different from that in patients without congenital heart disease. In normal hearts, electromechanical dyssynchrony is known to induce ventricular remodeling and heart failure. Ventricular asynchrony is also present in a substantial number of adults with congenital heart disease. In this study, we combined animal experiments and clinical studies to investigate: 1) the acute and chronic effect of biventricular resynchronization therapy on cardiac function in an animal model mimicking right ventricular heart failure in Tetralogy of Fallot, as well as in patients with Tetralogy of Fallot; 2) the consequences of conventional ventricular pacing in patients with ‘systemic right ventricle physiology’; 3) the effects of chronic right ventricular pacing in an animal model of the developing heart.We found that: 1) biventricular resynchronization induces significant hemodynamic benefit in the animal model of Tetralogy of Fallot as well as in Fallot patients; 2) ventricular asynchrony induced by conventional ventricular pacing is deleterious to the function of the systemic right ventricle; 3) chronic right ventricular pacing is harmful to the developing (pediatric) heart with normal biventricular anatomy. Cardiac resynchronization therapy is promising as a treatment for heart failure, but may also prevent heart failure. Nowadays, new implantation techniques allow us to implant pacing devices in patients with limited anatomical access due to prior surgery and help to avoid numerous severe complications of conventional pacing therapy

Ce mémoire par article est une étude des différences hémodynamiques entre la dextro-transposition des gros vaisseaux (TGV) avec communication interventriculaire (CIV) et la TGV avec septum intact (SI) pendant la période fœtale et périopératoire. Il est à noter que SI fait référence au septum inter ventriculaire et non au septum inter auriculaire. La présence d’une communication inter auriculaire étant, comme nous le verrons dans ce travail, un élément important de la physiologie des fœtus/nouveau-nés porteur de TGV. Le document est divisé en deux parties importantes. La première partie est composée du chapitre 1 qui présente une revue de littérature détaillant les notions importantes à la compréhension de la problématique et du chapitre 2 qui décrit la méthodologie utilisée pour répondre à la question de recherche. On détaille d’abord les méthodes d’acquisition des échocardiographies fœtales ainsi que les principales mesures effectuées à partir de celles-ci. Ensuite, on y décrit les technologies de la spectroscopie proche infrarouge avancée et de la spectroscopie à corrélation diffuse (NIRS-DCS) permettant de recueillir les données hémodynamiques sur la microvascularisation cérébrale des nouveau-nés. La seconde partie est constituée du chapitre 3 qui est le manuscrit accepté au journal Ultrasound in Obstetric & Gynecology pour publication. Celui-ci décrit les différences hémodynamiques entre les patients ayant une TGV&CIV et les TGV&SI et présente les différences retrouvées en échocardiographie fœtale et en hémodynamie cérébrale périopératoire étudiée à l’aide de la NIRS avancée. Ensuite, nous présentons dans le chapitre 4 une discussion sur les principaux impacts cliniques et sur d’éventuelles améliorations. / This master’sthesis is composed of an article and a study. They present hemodynamic differences between patients with transposition of the great arteries (TGA) and ventricular septum defect (VSD), and TGA with intact ventricular septum (IVS) during fetal and perioperative periods. This document is divided into two principal sections. The first section includes Chapter 1 that presents a review of literature detailing important notions to understand the problematic, and Chapter 2, that describes the methodology used to answer our research question. First, we detailed acquisition data and measured parameters of the fetal echocardiography exams. Then, we describe advanced near infrared spectroscopy (NIRS-DCS) technology that allowed hemodynamic data acquisition on the cerebral microvascularization of neonates. The second section is composed of Chapter 3, the manuscript accepted in Ultrasound in Obstetric & Gynecology journal for publication. The aim of this article is to describe hemodynamic differences between patients with TGA&VSD and TGA&IVS. It describes fetal echocardiography and cerebral perioperative hemodynamic differences studied with advanced NIRS. Next, we present in Chapter 4 a more detailed discussion with principal impacts on the clinical field and future improvements.