Development of the cardiac conduction system in atrioventricular septal defect in human trisomy 21.

In patients with atrioventricular septal defect (AVSD), the occurrence of nonsurgical AV block has been reported. We have looked for an explanation in the development of the AV conduction system. Human embryos with AVSD and trisomy 21 and normal embryos were examined (age 5-16 wk gestation).

Hb Oegstgeest [alpha104(G11)Cys-->Ser (alpha1)]. A new hemoglobin variant associated with a mild alpha-thalassemia phenotype.

A microcytic hypochromic anemic state was observed in an 8-year old Black female of Surinam origin during pre-operative Hb S [beta6(A3)Glu-->Val] screening. Her high zinc protoporphyrin (ZPP) level suggested a chronic iron depletion but, in contrast, the high red blood cell (RBC) count (5.85 x 10(12)/L) was indicative of a possible coexisting thalassemia.

Low-energy radiofrequency catheter ablation as therapy for supraventricular tachycardia in a premature neonate.

Unlabelled: A premature neonate with hydrops was born at 32 weeks of gestation after successful direct fetal amiodarone therapy via cordocentesis for incessant supraventricular tachycardia. After birth the tachycardia could not be controlled despite high doses of amiodarone and flecainide and the patient developed severe respiratory and circulatory failure. After 3 weeks, weighing 2 kg, he underwent successful and uncomplicated catheter ablation of a left free-wall accessory pathway using low-energy radiofrequency.

Implantable cardioverter defibrillator implantation in children in The Netherlands.

Unlabelled: To evaluate the indications, underlying cardiac disorders, efficacy and complications involved with implantable cardioverter-defibrillators (ICDs) in paediatric patients in The Netherlands, the records of all patients aged 18 years or younger who underwent ICD placement were reviewed retrospectively. Between January 1995 and September 2002, 23 patients (11 males, 12 females; median age 12 years, range 6 months to 16 years) underwent ICD implantation. The ICD was implanted for aborted sudden cardiac death ( n = 14), syncope ( n = 5) or for primary prevention of sudden cardiac death ( n = 4).

Intraoperative stenting of pulmonary arteries.

Objective: The surgical treatment of pulmonary artery stenoses in small children with complex cardiac lesions can be technically difficult. A hybrid-approach combining corrective surgery and intraoperative stent placement may be complementary in these patients.

Methods: Descriptive study in 11 small children (age: one week to 12 years, median of 12 months, weight: 2.

Sudden unexpected death in children with a previously diagnosed cardiovascular disorder.

Background: It is known that children with previously diagnosed heart defects die suddenly. The causes of death are often unknown.

Objective: The aim of the study was to identify all infants and children within the Netherlands with previously diagnosed heart disease who had a sudden unexpected death (SUD), and to identify the possible cause of death.

Embryonic conduction tissue: a spatial correlation with adult arrhythmogenic areas.

Introduction: The occurrence of arrhythmias in adult patients may arise preferentially in anatomic regions derived from the specialized cardiac conduction system. To examine this hypothesis, we performed a detailed analysis of the developing cardiac conduction system using the recently described CCS-lacZ transgenic mouse strain.

Methods And Results: Transgenic embryos (E9.

The influence of premature ventricular contractions on left ventricular function in asymptomatic children without structural heart disease: an echocardiographic evaluation.

Background: Isolated monomorphic premature ventricular contractions (PVCs) are not uncommon in the pediatric population. The degree of cardiac dysfunction caused by PVCs in children without structural heart disease is unknown.

Purpose: To investigate the influence of PVCs on echocardiographic left ventricular (LV) systolic function in children without structural heart disease.

Transvenous biventricular pacing in a child after congenital heart surgery as an alternative therapy for congestive heart failure.

Transvenous Biventricular Pacing in Children. Cardiac resynchronization therapy improves short-term and long-term hemodynamics in adult patients with congestive heart failure and left bundle branch block. We describe the feasibility of transvenous biventricular pacemaker implantation in a 6-year-old child with heart failure and wide QRS complex after congenital heart surgery.

Voltage and activation mapping: how the recording technique affects the outcome of catheter ablation procedures in patients with congenital heart disease.

Background: Endocardial mapping is mandatory before radiofrequency catheter ablation (RFCA). Mapping can be performed with either unipolar or bipolar recordings. Impact of the recording technique used was studied in patients with and without structural heart disease using the 3D electroanatomic CARTO mapping system.

Resynchronization therapy after congenital heart surgery to improve left ventricular function.

This report describes the mid-term beneficial hemodynamic effect of biventricular pacing in an infant with congestive heart failure after congenital heart surgery, due to resynchronization of the left and right ventricle, optimization of the AV delay, and (partial) correction of the LV dyssynchrony.

The role of neural crest and epicardium-derived cells in conduction system formation.

During cardiac development the heart tube loops and is septated into a four-chambered structure. The initial peristaltic contraction of the primitive myocardium is replaced by a system of working myocardium and a myocardial-derived central and peripheral conduction system. The genes guiding this differentiation process are still under investigation and it has yet to be decided whether we are dealing with a recruitment or a specification model.

Deficiency of the vestibular spine in atrioventricular septal defects in human fetuses with down syndrome.

Data on the morphogenesis of atrioventricular septal defect (AVSD) in Down syndrome are lacking to support molecular studies on Down syndrome heart critical region. Therefore, we studied the development of complete AVSD in human embryos and fetuses with trisomy 21 using 3-dimensional graphic reconstructions and immunohistochemical markers. Eight trisomic hearts with AVSD and 10 normal hearts, ranging from 5 to 16 weeks' gestation, were examined.

Major coronary anomalies in childhood.

Unlabelled: Major coronary artery anomalies are extremely rare in childhood. We wanted to assess the historical and diagnostic features and the therapeutic options of three distinct types of coronary artery anomalies: abnormal origin of the left coronary artery from the pulmonary artery (ALCAPA), coronary fistula and coronary stenosis. In a retrospective study, 33 children with these types of coronary artery disease were identified, 15 with ALCAPA, 12 with fistula and six with coronary stenosis.

Isolated unilateral absence of a pulmonary artery: a case report and review of the literature.

Objective: The purpose of the present study was to determine the symptomatology, diagnostic procedures, and therapeutic strategies of patients with an isolated unilateral absence of a pulmonary artery (UAPA).

Background: Isolated UAPA is a rare anomaly. Some case reports exist, but the best diagnostic and therapeutic approaches to these patients remain unclear.