Cardiac development : the posterior heart field and atrioventricular reentry tachycardia

This thesis is separated in two parts (Part I and Part II) in which normal and abnormal heart development are studied and related to congenital heart disease, in particular to the etiology of supraventricular arrhythmias in fetuses and neonates. Part I describes the development of the posterior heart field derived venous pole of the heart specifically in correlation to the role of Shox2 and podoplanin in that particular area. Furthermore, the developmental processes in this region seem to have an important role in the anlage of the cardiac conduction system and epicardial lineage development of the heart. In the second part of this thesis (Part II) the aetiology of a specific subtype of supraventricular tachycardias i.e. atrioventricular reentry tachycardias (AVRTs) are related to normal heart development in human and mouse. AVRTs are one of the most common types of tachyarrhythmias at the perinatal period of development. We demonstrate that perinatal AVRTs might be related to incomplete formation of the isolating annulus fibrosus resulting in the temporary persistence of accessory myocardial connections between the atria and ventricles. We furthermore, demonstrate the late outcome of fetal brady- and tachyarrhythmia cases.UBL - phd migration 201

The Resilience of Recently Graduated and Unemployed Dutch Academics in Coping with the Economic Crisis

Some years after the world-wide crisis starting in 2008, also many recently graduated Dutch academics were confronted with the problem of how to cope with getting a job. This article focuses on the coping strategies they use when searching after a job, spending the day, and coping with limited financial means. 91 graduated academics completed a survey and twelve more were interviewed. They exposed remarkable resilience in coping with their situation by using emotional and problem oriented coping strategies. Emotional oriented coping strategies resulted in the graduates being able to put their situation of being without a regular job into perspective, structuring their days rather easily, and being pleased with how they did it. Their problem oriented coping strategies showed willingness to look for a job outside their field of study and below an academic level. Some respondents were willing to do unpaid work to get enrolled in the job market. The rather constructive way of coping can be explained partly by their relatively favourable financial position, mostly due to their temporary or side jobs, which also gave them a way to spend their days. Thus, the recently graduated academic job seekers perceived their economic situation in a rather positive way. Whether this was influenced by their level of education should be an important subject for more research

Ductal flow ratio as a measure of transition in preterm infants after birth: a pilot study

Background: Cardiovascular changes during the transition from intra- to extrauterine life, alters the pressure gradient across the ductus arteriosus (DA). DA flow ratio (R-L/L-R) has been suggested to reflect the infant's transitional status and could potentially predict neonatal outcomes after preterm birth.Aim: Determine whether DA flow ratio correlates with oxygenation parameters in preterm infants at 1 h after birth.Methods: Echocardiography was performed in preterm infants born < 32 weeks gestational age (GA), as part of an ancillary study. DA flow was measured at 1 h after birth. DA flow ratio was correlated with FiO(2), SpO(2), and SpO(2)/FiO(2) (SF) ratio. The DA flow ratio of infants receiving physiological-based cord clamping (PBCC) or time-based cord clamping (TBCC) were compared.Results: Measurements from 16 infants were analysed (median [IQR] GA 29 [27-30] weeks; birthweight 1,176 [951-1,409] grams). R-L DA shunting was 16 [17-27] ml/kg/min and L-R was 110 [81-124] ml/kg/min. The DA flow ratio was 0.18 [0.11-0.28], SpO(2) 94 [93-96]%, FiO(2) was 23 [21-28]% and SF ratio 4.1 [3.3-4.5]. There was a moderate correlation between DA flow ratio and SpO(2) [correlation coefficient (CC) -0.415; p = 0.110], FiO(2) (CC 0.384; p = 0.142) and SF ratio (CC -0.356; p = 0.175). There were no differences in DA flow measurements between infants where PBBC or TBCC was performed.Conclusion: In this pilot study we observed a non-significant positive correlation between DA flow ratio at 1 h after birth and oxygenation parameters in preterm infants.Developmen

Echocardiographic Assessment of Embryonic and Fetal Mouse Heart Development: A Focus on Haemodynamics and Morphology

Background. Heart development is a complex process, and abnormal development may result in congenital heart disease (CHD). Currently, studies on animal models mainly focus on cardiac morphology and the availability of hemodynamic data, especially of the right heart half, is limited. Here we aimed to assess the morphological and hemodynamic parameters of normal developing mouse embryos/fetuses by using a high-frequency ultrasound system. Methods. A timed breeding program was initiated with a WT mouse line (Swiss/129Sv background). All recordings were performed transabdominally, in isoflurane sedated pregnant mice, in hearts of sequential developmental stages: 12.5, 14.5, and 17.5 days after conception (n=105). Results. Along development the heart rate increased significantly from 125 ± 9.5 to 219 ± 8.3 beats per minute. Reliable flow measurements could be performed across the developing mitral and tricuspid valves and outflow tract. M-mode measurements could be obtained of all cardiac compartments. An overall increase of cardiac systolic and diastolic function with embryonic/fetal development was observed. Conclusion. High-frequency echocardiography is a promising and useful imaging modality for structural and hemodynamic analysis of embryonic/fetal mouse hearts

Perinatal management and long-term cardiac outcome in fetal arrhythmia

Item does not contain fulltextBACKGROUND: cardiac arrhythmias are commonly observed in the fetus, however, may have major consequences for fetal development and post natal life. AIMS: to evaluate the perinatal management and cardiac outcome of fetuses with tachy- or bradyarrhythmia. STUDY DESIGN: perinatal management, outcome and long-term cardiac follow-up were evaluated retrospectively in consecutive fetuses with cardiac arrhythmias. RESULTS: forty-four fetuses were diagnosed: supraventricular tachycardia (SVT, n=28), atrial flutter (AF, n=7) and atrioventricular block (AVB, n=9). The overall incidence of cardiac anomalies was 18% mainly in the AVB group; hydrops was present in 34%. Direct or transplacental fetal anti-arrhythmic medication was given in 76%. Mortality was 6% in SVT/AF and 78% in the AVB group, respectively. AF resolved in all patients. In the SVT group, Wolff-Parkinson-White (WPW) syndrome was present in 21%, diagnosed at birth or later in life. After the age of one year about 90% of patients in the SVT group remained asymptomatic and free of drugs (median follow-up 76months). CONCLUSIONS: mortality rate is low in patients with fetal SVT and AF but high in patients with AVB. Related morbidity includes WPW-syndrome and congenital cardiac anomalies. Electrocardiographic screening is recommended in all fetal SVT cases before adolescence since WPW-syndrome may occur later in life

Accessory Atrioventricular Myocardial Pathways in Mouse Heart Development: Substrate for Supraventricular Tachycardias

Cardiac Dysfunction and Arrhythmia

Normal and abnormal development of the cardiac conduction system; implications for conduction and rhythm disorders in the child and adult

Cardiolog

Ductal Flow Ratio as Measure of Transition in Preterm Infants After Birth

Background: Cardiovascular changes during the transition from intra- to extrauterine life, alters the pressure gradient across the ductus arteriosus (DA). DA flow ratio (R-L/L-R) has been suggested to reflect the infant's transitional status and could potentially predict neonatal outcomes after preterm birth. Aim: Determine whether DA flow ratio correlates with oxygenation parameters in preterm infants at 1 h after birth. Methods: Echocardiography was performed in preterm infants born &lt;32 weeks gestational age (GA), as part of an ancillary study. DA flow was measured at 1 h after birth. DA flow ratio was correlated with FiO2, Sp

Fetal echocardiography of a Vegf overexpression model shows impaired sino-atrial nodal function consistent with abnormal morphology

Developmen

Echocardiographic Assessment of Embryonic and Fetal Mouse Heart Development: A Focus on Haemodynamics and Morphology

Cardiolog