A case of an infant with flail tricuspid valve due to spontaneous papillary muscle rupture: was neonatal lupus the culprit?

A 3-month-old infant presented in extremis with a flail tricuspid valve. The authors theorized that the genesis of her papillary muscle rupture was perinatal ischemia compounded by worsening pulmonary valvular stenosis leading to excessive fiber tension. Her underlying diagnosis of autoimmune-mediated heart block with endocardial fibroelastosis and prenatal glucocorticoid steroid treatment represents potentiating factors.

Modified Norwood operation for hypoplastic left heart syndrome

BACKGROUND

We examined early results in infants with hypoplastic left heart syndrome undergoing the Norwood operation with perioperative use of inhaled nitric oxide and application of extracorporeal membrane oxygenation.

METHODS

Medical records were reviewed retrospectively.

RESULTS

Between April 1997 and March 2001, 50 infants underwent a modified Norwood operation for hypoplastic left heart syndrome. Mean age at operation was 7.5 +/- 5.7 days, and mean weight was 3.1 +/- 0.5 kg. Five infants had a delayed operation because of sepsis. The mean diameter of the ascending aorta by echocardiography was 3.6 +/- 1.8 mm. Ductal cannulation was used to establish cardiopulmonary bypass in all patients. Mean circulatory arrest time was 39.4 +/- 4.8 minutes. The size of the pulmonary-systemic shunt was 3.0 mm in 6 infants, 3.5 mm in 37, and 4.0 mm in 7. Infants with persistent hypoxia (partial pressure of oxygen < 30 mm Hg) received nitric oxide after they were weaned from cardiopulmonary bypass. Extracorporeal membrane oxygenation was initiated in 8 infants in the pediatric intensive care unit primarily for low cardiac output and in 8 in the operating room because of the inability to separate them from cardiopulmonary bypass. The 30-day mortality rate was 22% (11 of 50 patients), and the hospital mortality rate was 32% (16 of 50 patients). Mean follow-up was 17 months. Ten patients (20%) underwent stage-two repair, with one operative death. One survivor had a Fontan procedure, and 2 underwent heart transplantation, with one death.

CONCLUSIONS

Early application of extracorporeal membrane oxygenation for hemodynamic instability and selective use of nitric oxide for persistent hypoxia in the immediate postoperative period may improve survival of patients with hypoplastic left heart syndrome. Renal failure requiring hemofiltration during extracorporeal membrane oxygenation (p < 0.05) and cardiopulmonary arrest in the pediatric intensive care unit (p < 0.05) were predictors of hospital mortality.

Transesophageal echocardiography in pediatric congenital heart disease

The uses of transesophageal echocardiography have expanded dramatically over the last decade. With advances in technology, this imaging modality has become readily available for evaluation of the complex pediatric population with congenital heart disease. This article discusses the many uses of transesophageal echocardiography in this population, in the outpatient setting, in the peri-operative period, and in the cardiac catheterization laboratory.

Mutations in the cardiac transcription factor NKX2.5 affect diverse cardiac developmental pathways

Heterozygous mutations in NKX2.5, a homeobox transcription factor, were reported to cause secundum atrial septal defects and result in atrioventricular (AV) conduction block during postnatal life. To further characterize the role of NKX2.5 in cardiac morphogenesis, we sought additional mutations in groups of probands with cardiac anomalies and first-degree AV block, idiopathic AV block, or tetralogy of Fallot. We identified 7 novel mutations by sequence analysis of the NKX2.5-coding region in 26 individuals. Associated phenotypes included AV block, which was the primary manifestation of cardiac disease in nearly a quarter of affected individuals, as well as atrial septal defect and ventricular septal defect. Ventricular septal defect was associated with tetralogy of Fallot or double-outlet right ventricle in 3 individuals. Ebstein's anomaly and other tricuspid valve abnormalities were also present. Mutations in human NKX2.5 cause a variety of cardiac anomalies and may account for a clinically significant portion of tetralogy of Fallot and idiopathic AV block. The coinheritance of NKX2.5 mutations with various congenital heart defects suggests that this transcription factor contributes to diverse cardiac developmental pathways.

Low incidence of significant valvar insufficiency following retrograde aortic radiofrequency catheter ablation in young patients

The incidence of significant valvar insufficiency at late (<6 month) follow-up was retrospectively evaluated in 27 young patients (age 4. 0-18.0 years) undergoing 29 ablation procedures via the retrograde aortic approach for left-sided accessory connections in whom pre-ablation and post-ablation echocardiograms were available for review. Valvar insufficiency was graded using color flow techniques as absent, trivial, mild, moderate, or severe by blinded reviewers. Ablation was acutely successful via the retrograde approach in 25 of 29 procedures among these 27 patients. Successful ablation was ultimately achieved in all 27 patients. At baseline, 7 patients had evidence of trivial or mild mitral insufficiency, and no patient had aortic insufficiency. Three patients had evidence of impaired left ventricular systolic performance in the presence of manifest pre-excitation. At follow-up, pre-existing mitral insufficiency resolved in 5/7 patients, and persisted in 2 patients. New mitral insufficiency was evident in 3 patients, and new aortic insufficiency was transiently evident in 1 patient following ablation (all trivial). Institutional experience (mean rank 10 cases vs. 33 cases, p <.0005), and lower patient weight (29.7 vs. 56.3 kilograms, p =.01) were the only factors associated with the development of new valvar insufficiency. Valvar insufficiency could not be detected by careful auscultation in any patient and was deemed clinically insignificant in all patients. We conclude that ablation of left-sided accessory connections can be performed via the retrograde aortic approach without creating clinically significant valvar insufficiency.

Endocarditis caused by group A beta-hemolytic Streptococcus in an infant: case report and review

Acute bacterial endocarditis in the absence of underlying heart disease is rare. We report the occurrence of endocarditis caused by group A beta-hemolytic Streptococcus (GABHS), following varicella, in a 5-month-old child without heart disease. In addition to this child, seven other children with endocarditis caused by GABHS have been reported since 1966, six of whom did not have preexisting heart disease. In one of these children, GABHS endocarditis was preceded by varicella. These cases indicate that GABHS is capable of causing endocarditis in the absence of heart disease, and they provide further evidence that varicella is an important risk factor for invasive GABHS infections.

Hypoplastic left heart syndrome: anesthetic care prior to transplantation or surgical palliation

Hypoplastic left heart syndrome is the most common lethal cardiac defect in neonates. Options for treatment include cardiac transplantation and surgical palliation. When cardiac transplantation is chosen as the preferred option, a considerable delay may occur until a suitable donor is available. During this time, anesthetic care may be required for various surgical procedures. Associated anomalies seen in these infants and the anesthetic implications imposed by the abnormal cardiac anatomy are discussed.

Noninvasive assessment of myocardium at risk by Tl-201 SPECT imaging in a child with Kawasaki disease. A case report

Serial two-dimensional echocardiograms documented the formation of giant aneurysms, measuring from 0.55 to 3.1 cm in diameter, in the distribution of the left and right coronary arteries, in a 2 1/2-year-old boy with Kawasaki disease. His global left ventricular function, assessed by M-mode echocardiography, was normal, and no significant wall motion abnormalities could be detected on two-dimensinal evaluation. Cardiac catheterization showed multiple aneurysms with no evidence of stenosis. Although he had no clinical symptoms or electrocardiographic evidence of ischemia, pharmacologic stress and delayed Tl-201 SPECT images revealed prominent stress-induced myocardial ischemia in the left ventricle. A resting gated blood pool study showed hypokinesia in corresponding regions of the left ventricle. This case demonstrates the usefulness of Tl-201 myocardial SPECT imaging and resting gated blood pool studies in the management of coronary artery disease in children with Kawasaki disease.

Acute infantile cardiomyopathy as a presenting feature of mucopolysaccharidosis VI

An infant with a diagnosis of acute infantile cardiomyopathy was subsequently shown to have mucopolysaccharidosis VI. The mucopolysaccharidoses should be included in the differential diagnosis of infantile cardiomyopathy.