Complete Atrioventricular Septal Defect and Ebstein's Anomaly

A case child with complete atrioventricular septal defect (AVSD) and Ebstein's anomaly underwent surgical treatment at 3 months of age. She died on the third postoperative day. Postmortem examination showed complete AVSD, downward displacement of the right atrioventricular valve, left ventricular outflow tract obstruction, and hypertensive pulmonary vascular disease. Association of complete AVSD and Ebstein's anomaly is a rare cardiac anomaly for which no attempt at surgical repair has previously been made. This report deals with our experience and also with the morphological features of this anomaly.     

Inhaled Nitric Oxide Therapy in a Critically Ill Neonate with Ebstein's Anomaly

The successful use of nitric oxide (NO) inhalation in a critically ill neonate with Ebstein's anomaly of the tricuspid valve is reported for the first time. This use of inhaled NO therapy suggests a therapeutic intervention that directly addresses the pathophysiologic process of severe neonatal Ebstein's anomaly.     

Exercise Testing in Children with Pulmonary Valvar Stenosis

Pulmonary valvar stenosis with intact ventricular septum is a common anomaly. This lesion poses a fixed obstruction to the right ventricular outflow. The right ventricle ejects the entire cardiac output across the stenotic valve. Right ventricular systolic pressure and oxygen demand are increased at rest and more so with exercise. Exercise tolerance in children and adults with mild valvar pulmonary stenosis is nearly normal, but is diminished in those with moderate and severe stenosis, indicating impaired ability to sustain adequate cardiac output. Following relief of stenosis, cardiac performance improves in children, but remains abnormal in adults. This appears to be related to postoperative resolution of right ventricular hypertrophy in children, whereas myocardial fibrosis may explain the lack of improvement in adults.     

Exercise Tolerance and Blood Pressure Response to Exercise Testing in Children and Adolescents After Renal Transplantation

The aim of the study was to assess exercise tolerance and blood pressure (BP) response to treadmill exercise in children after renal transplantation. Forty-five children were selected (29 males and 16 females) whose mean age was 14.3 ± 4.2 years. All children had Hb ≥ 10 g/dl and creatinine clearance ≥40 ml/min/1.73 m². They were at least 6 months posttransplantation and were on triple immunosuppressive therapy. Twenty-seven were also on various antihypertensive medications. Each underwent clinical examination and measurement of BP, both at rest and during exercise testing on treadmill. The test was stopped on muscular fatigue or exhaustion. The patients were divided into two groups: those off (A) or on (B) antihypertensive therapy. When compared to a population of healthy children the patients had reduced exercise tolerance (10.1 ± 2.1 vs 15.1 ± 1.7 min, p < 0.001) (67 ± 16%), increased heart rate (174 ± 19 vs 161 ± 19 beats/min, p < 0.001) (109 ± 15%), and increased maximum systolic BP (150 ± 26 vs 134 ± 13 mmHg, p < 0.001) (113 ± 19%) at comparable workloads. Within the two patient groups, significant differences were observed during exercise testing for maximum heart rate, which was lower in group B (p= 0.03), and maximum systolic BP, which was higher in group A (p= 0.04). Our study confirms that children and adolescents on immunosuppressive therapy after renal transplantation have a hypertensive response during exercise, probably related to medication-induced peripheral vascular tone.     

Exercise Testing of the Child with Obesity

As the prevalence of childhood obesity increases, exercise testing of obese children is likely to increase as well. This article discusses the implications of pediatric obesity for exercise testing and provides some recommendations for conducting tests and evaluating results. Studies comparing obese and nonobese children during exercise testing indicate that obese children are capable of meeting the challenges of exercise testing to nearly the same extent as their nonobese peers. Their physiologic responses, at least for the levels of obesity reported in the literature, are not sufficiently different from their nonobese counterparts to necessitate major changes in test protocols. Laboratory staff should pay special attention to fostering confidence in the obese child during the pretest routine.     

Exercise Testing in Children with Primary Pulmonary Hypertension

Cardiopulmonary exercise testing is a useful noninvasive tool to assess physiological changes associated with exercise. Developing noninvasive methods to assess the severity of cardiopulmonary disorders, as well as the response to therapeutic interventions, is useful in conditions, such as primary pulmonary hypertension, in which invasive procedures carry significant risks. The 6-minute walk test is a simple measure of exercise endurance. Exercise studies that measure both hemodynamic and ventilatory responses provide additional information regarding the interaction of the circulatory and pulmonary systems. Subtle changes in exercise capacity may suggest deterioration prior to clinical manifestations. This may lead to an earlier reevaluation, including repeat cardiac catheterization, and subsequently changes in medical and/or surgical therapy.     

Congenital Malformations of the Tricuspid Valve in Siblings

The occurrence of familial heart disease in association with tricuspid atresia is rare. The first reported instance of tricuspid atresia and Ebstein's anomaly in siblings is presented. The presence of these two distinct pathologic variants of tricuspid valve malformations in siblings suggests that these malformations result from a common abnormality occurring during the development of the inlet portion of the right ventricle.     

Osteogenesis Imperfecta and Ebstein's Anomaly: A case Report with Autopsy Findings

Osteogenesis imperfecta is an inherited disorder of collagen synthesis. It has a wide range of phenotypic expressions, but cardiovascular anomalies tend to be rare. When they do occur, they usually consist of aortic or mitral valve disease. We report an autopsy case of a 36-week gestation infant with coexisting osteogenesis imperfecta and Ebstein's anomaly. The simultaneous occurrence of two relatively rare entities may reflect a generalized expression of an underlying collagen synthesis defect.     

Autonomic Changes and Heart Rate Variability in Children with Neurocardiac Syncope

This study evaluated resting autonomic function and autonomic responses to head-up tilt-table testing in children who experienced neurocardiac syncope to determine whether predictable differences existed between these patients and normal volunteers. Neurocardiac syncope is a common cause of syncope in children. The mechanism, though related to abnormalities in autonomic function, has not been fully elucidated, particularly in pediatric patients. This study evaluated resting autonomic tone using noninvasive autonomic function tests (i.e., Valsalva, handgrip, and deep breathing) and 24-hour heart rate variability (HRV). In addition, heart rate and blood pressure were evaluated during head-up tilt examination. Values from patients who experienced neurocardiac syncope were compared to those from age-matched normal volunteers. No significant differences were noted during noninvasive testing. Some time domain HRV variables demonstrated a trend toward significant difference (p < 0.10). Tilt testing data were significantly different in sinus beat to sinus beat (RR) intervals between controls and syncope patients at 2, 5, and 10 minutes after tilting. In addition, significant differences were noted in RR interval and the standard deviation of RR interval 1 or 2 minutes prior to syncope when compared to controls at 5 and 10 minutes after tilting. Children with syncope exhibited abnormalities during tilt testing indicating an increased sympathetic or decreased parasympathetic tone, particularly prior to syncope. Some measures of HRV might constitute noninvasive parameters that correlate with the positive tilt table test.     

Dental Bacteremia in Children

Bacteremia resulting from dental extraction is regarded as an important cause of bacterial endocarditis, and it is therefore recommended that patients undergoing tooth extraction be given prophylactic antibiotics. As dental procedures other than extractions may also cause bacteremias, we studied a variety of dental procedures routinely used in pediatric dentistry. Blood samples for cultures were obtained 30 s after each of 13 dental operative procedures in 735 anesthetized children aged 2–16 years. Four procedures used for conservative dentistry caused bacteremias significantly more often than the baseline value of 9.4%: polishing teeth 24.5%, intraligamental injection 96.6%, rubber dam placement 29.4%, and matrix band with wedge placement 32.1%. In comparison, toothbrushing alone caused a bacteremia on 38.5% of occasions. The organisms isolated were typical of odontogenic bacteremias in that 50% of the isolates were identified as varieties of viridans streptococci. These data show that a wider variety of dental procedures than was previously documented cause bacteremia.     

Pathologic Lung Function in Children and Adolescents with Congenital Heart Defects

Lung function tests (i.e., spirometry, flow volume, and body plethysmography) were performed in 213 patients (age 6–21 years, mean 11.3 years) with hemodynamically significant congenital heart defects: atrial septal defect, ventricular septal defect (VSD), tetralogy of Fallot, aortic stenosis and coarctation of the aorta. We measured lung vital capacity, total lung capacity (TLC), residual volume (RV), the percentage ratio of the latter two measurements (%RV/TLC), maximal expiratory flow rates at 25% and 50% of vital capacity, and specific airway conductance. Pulmonary restriction dominated in patients with tetralogy of Fallot; pulmonary hyperinflation was more frequent in patients with VSD and coarctation of the aorta; and obstruction of the airways was observed most frequently in patients with tetralogy of Fallot. In conclusion, we found a range of pathologic lung function parameters in patients with hemodynamically significant congenital heart defects.     

Incidence of Femoral Vein Occlusion After Catheter Ablation in Children: Evaluation with Magnetic Resonance Angiography

Catheter ablation in children requires placement of multiple large femoral venous sheaths and catheters. Magnetic resonance angiography (MRA) was used to evaluate the effect of indwelling lines on femoral venous blood flow. Between October 1993 and February 1994 a total of 17 patients scheduled for catheter ablation underwent venous MRA. Two-dimensional time-of-flight MRA was performed 12–70 hours after catheterization on all patients. All patients received intravenous heparin during the procedure and had aspirin therapy instituted after ablation. Eighteen catheter ablations and MRA studies were performed on the 17 patients (one patient underwent repeat ablation). There were 7 females and 10 males, with a mean age of 14.8 ± 4.2 years (range 8–21 years). Patients had three venous sheaths inserted in the left femoral vein (5F, 6F, and 7F with external diameters measuring 1.7, 2.0, and 2.3 mm, respectively) and one sheath in the right femoral vein (7F). Four patients (22%) had altered venous flow (two complete obstructions and two partial obstructions) following catheterization. None of these patients experienced symptoms or complications. It was concluded that there is an increased incidence (22%) of venous obstruction following catheter ablation, but there are no related complications. Venous MRA provides a rapid, noninvasive method for evaluating venous flow abnormalities and possibly detects patients at risk for complications.     

Exercise Testing as a Rehabilitative/Training Tool

Exercise testing is an exceedingly useful noninvasive method for assessing cardiovascular function not only at rest but also during programmed, supervised physical exercise. Exercise testing has been intensively studied to delineate the cardiovascular response in various disorders [3–5, 15, 19, 22, 23, 26, 32]. Exercise testing as a tool for rehabilitation and for training to perform physical activity is discussed here.     

Cerebral Oxygenation in Children with Syncope During Head-Upright Tilt Test

The pathophysiology of neurocardiogenic syncope remains incompletely known. In this entity, besides abnormal systemic hemodynamic regulation, potential cerebral circulatory abnormalities have been reported. In this setting, cerebral saturation assessment could detect cerebral blood flow changes and estimate the sufficiency of brain oxygenation during the event. A head-upright tilt test was performed in 25 children aged between 6 and 16 years. In addition to the standard protocol, cerebral oxygen saturation was determined noninvasively by means of a near-infrared spectrophotometry device. In the 19 children with a positive tilt test, significant impairment of cerebral saturation was detected both at the start of the patient's complaints (without hemodynamic modifications) and during syncope. Our results support the hypothesis of the presence of abnormal cerebral hemodynamic autoregulation in children with neurocardiogenic syncope.     

Pre- and Postoperative Exercise Testing of the Child with Coarctation of the Aorta

Exercise studies in patients with coarctation of the aorta (CoA) are reviewed. A brief survey of the natural history of unoperated CoA, the pioneers who reported the first operative repair, and comments on blood pressure measurements are provided. Preoperative and postoperative (postop) exercise studies of patients with CoA are also reviewed. The various etiological factors which may contribute to hypertension found in some post-op CoA patients are discussed.