Patent ductus arteriosus in preterm infants: is early transcatheter closure a paradigm shift?

The optimal management approach of the patent ductus arteriosus (PDA) in premature infants remains uncertain owing the lack of evidence for long-term benefits and the limited analyses of the complications of medical and surgical interventions to date. In recent years, devices suitable to plug the PDA of premature infants (including extremely low birthweight, <1000 g) have become available and several trials have demonstrated successful and safe transcatheter PDA closure (TCPC) in this population. Whether TCPC represents a paradigm shift in PDA management that will result in improved short- and long-term outcomes, less bronchopulmonary dysplasia, improved neurodevelopment, or better long term renal function remains to be seen. Careful rigorous study of the potential benefits of TCPC in this highly vulnerable population in the context of well-designed adequately powered trials is needed prior to widespread adoption of this approach.

Implantable cardioverter defibrillator therapy in children with long QT syndrome.

We report our experience with implantable cardioverter defibrillator (ICD) implantation and follow-up in high-risk patients with congenital long QT syndrome (LQTS). Congenital LQTS is associated with significant risk of malignant ventricular arrhythmias and sudden cardiac death (SCD). ICD implant is recommended for prevention of SCD in this patient population, but there are few published data regarding the efficacy and side effects of such therapy. We report our experience with 12 patients who underwent ICD implant for high-risk LQTS at our center in the past 5 years with respect to implant complications, appropriate and inappropriate therapies, device follow-up, and the impact on lifestyle. During a follow-up of 34.7+/-16.6 months, appropriate therapies were noted in 5, inappropriate therapies in 4, and no therapies in 3 patients. Clusters of appropriate therapies were seen in 3 patients, 1 of whom subsequently died. Female sex and congenital deafness appear to be associated with a higher risk of appropriate therapies. One patient experienced two complications at implant that were successfully treated. ICD implantation in LQTS patients presenting with SCD or recurrent syncope despite beta-blocker therapy appears to be justified in preventing SCD risk. In asymptomatic siblings of SCD patients, the benefits of ICD implant are not clear from our data.

Prospective identification of anomalous origin of left coronary artery from the right sinus of valsalva using transthoracic echocardiography: importance of color Doppler flow mapping.

Four cases are discussed in which anomalous origin of the left coronary artery from the right sinus of Valsalva was identified prospectively by transthoracic echocardiography when the anomalous coronary passed between the great arteries. Color Doppler flow mapping was a critical component in identifying the anomalous coronary, particularly when the proximal course of the left main coronary was intramural.

Factors affecting longevity of homograft valves used in right ventricular outflow tract reconstruction for congenital heart disease.

BACKGROUND: Few studies have explored the long-term function of cryopreserved homograft valves used for reconstruction of the right ventricular tract (RVOT) in patients with congenital heart disease. METHODS AND RESULTS: Among 205 patients receiving cryopreserved homografts for reconstruction of the RVOT between November 1985 and April 1999, the outcome of 220 homografts in 183 operative survivors was analyzed. There were 150 pulmonary and 70 aortic homografts used. Median age at implantation was 4.4 years (mean 6.9+/-7.6 years, range 3 days to 48 years). End points included (1) patient survival, (2) homograft failure (valve explant or late death), and (3) homograft dysfunction (homograft insufficiency or homograft stenosis). Survival was 88% at 10 years. Freedom from homograft failure was 74+/-4% at 5 years and 54+/-7% at 10 years. Univariable analysis identified younger age, longer donor warm ischemic time, valve Z: value <2, and previous procedure as risk factors for homograft failure and dysfunction. Aortic homograft type and extracardiac operative technique predicted homograft failure but not dysfunction. For patients

Evaluation of the pediatric patient with a cardiac murmur.

In conclusion, the evaluation of cardiac murmurs represents one of the most skilled and demanding aspects of the pediatric physical assessment. It does provide a significant service to patients and a level of satisfaction for competent practitioners, and referral is not always warranted. The decision for referral is based on the presumed diagnosis, confidence of the examiner, and level of parental anxiety. Most often, referral to a cardiologist for directed investigation rather than direct echocardiographic assessment serves patients best.

Advances in the care of children with heart disease.

As we enter the next millennium, we are encouraged by the progress that has been made in the care of neonates, infants, and children with heart disease. Surgical repair can be offered at an earlier age with excellent results. Diseases that were uniformly fatal in the past have improved outcomes. Research continues in the area of interventional devices such that surgical repair might be eliminated or delayed. We continue to look forward to advances in the next several years that will allow for future improvement in outcome, better quality-of-life and better long-term results.

The cardiac murmur. When to refer?

This review article outlines the significance and defines the skills important for the diagnosis and recognition of common innocent cardiac murmurs in childhood. The origin of heart sounds and murmurs is reviewed, and an approach to pediatric murmur evaluation is presented. The seven innocent murmurs of childhood and adolescence are reviewed in detail. Further diagnostic evaluation and referral is dependent on the comfort factor and experience in recognition and correct characterization of these murmurs.

Aprotinin improves outcome of single-ventricle palliation.

BACKGROUND: Elevation of pulmonary vascular resistance as a consequence of cardiopulmonary bypass may lead to failure of single-ventricle palliation. We reviewed our experience with aprotinin, a nonspecific serine protease inhibitor, to determine whether it could ameliorate the inflammatory effects of cardiopulmonary bypass and improve outcome of single-ventricle palliation. METHODS: Forty-six consecutive patients undergoing single-ventricle palliation using cardiopulmonary bypass were reviewed retrospectively. Aprotinin was used in 8 of 30 bidirectional cavopulmonary shunt and 10 of 16 Fontan procedures. RESULTS: Aprotinin use was associated with a decrease in the early postoperative transpulmonary gradient among patients undergoing Fontan and bidirectional cavopulmonary shunt procedures. The bidirectional cavopulmonary shunt aprotinin group had a higher oxygen saturation and a decrease in quantity and duration of thoracic drainage. Among patients receiving aprotinin there were no episodes of mediastinitis, thrombus formation, or renal failure. CONCLUSIONS: Aprotinin use in single-ventricle palliation was associated with decreased transpulmonary gradient and increased oxygen saturation consistent with decreased pulmonary vascular resistance. This retrospective study suggests that aprotinin has a favorable impact on the early postoperative course of single-ventricle palliation.

Verapamil sensitive incessant ventricular tachycardia in the newborn.

Incessant VTs in infancy are often poorly tolerated. Response to conventional antiarrhythmic therapy is disappointing. The present case involves a 3-week-old infant with an incessant VT of a left bundle branch block, and normal axis morphology. This tachycardia was inducible with both atrial and ventricular pacing, but not by premature stimulation. Tachycardia persisted despite treatment with adenosine, esmolol, procainamide, and flecainide. Intravenous verapamil suppressed tachycardia and prevented inducibility, and no further recurrences were seen on oral verapamil. This case suggests that some incessant VTs in infancy may be due to calcium channel related afterdepolarizations or triggered activation.

Twenty-year experience with repair of complete atrioventricular septal defects.

BACKGROUND: To determine factors predicting mortality and morbidity after repair of complete atrioventricular septal defect, we retrospectively analyzed preoperative, operative, and postrepair factors on the outcome of 115 consecutive complete atrioventricular septal defect repairs at The Children's Hospital of Wisconsin between January 1974 and December 1993. METHODS: For the entire experience the operative mortality was 13.9% (16 patients). During the most recent era, January 1988 to December 1993, operative mortality was 3.6% (2 of 55 patients). This was significantly improved from the two previous eras, January 1974 to December 1980, 28% (7 of 25) and January 1981 to December 1987, 20% (7 of 35 patients) (p = 0.02). There were seven late deaths; 10-year actuarial survival, including operative mortality was 81%. Age at complete repair decreased; before 1982 all patients were more than 12 months of age, whereas after 1982 64% (56 of 88 patients) were 12 months of age or less. RESULTS: Moderate or severe preoperative left atrioventricular valve regurgitation was not a risk factor for operative mortality. For operative survivors with moderate to severe preoperative left atrioventricular valve regurgitation (n = 17), late postoperative left atrioventricular valve regurgitation (follow-up data available on 15 patients) was significantly reduced (severe = 1, moderate = 5, mild = 9; p = 0.007). CONCLUSIONS: Early mortality was predicted by the era of surgical repair. Conversion to routine repair during infancy was achieved with a simultaneous decrease in operative mortality. For patients with moderate to severe preoperative left atrioventricular valve regurgitation, significant improvement in the degree of left atrioventricular valve regurgitation can be expected without an increase in operative or late mortality or morbidity.

Stroke volume during exercise in cystic fibrosis.

Previous studies comparing cardiac output (Q) and stroke volume (SV) between cystic fibrosis (CF) patients and control subjects have shown conflicting results: some found lower SV in CF patients with severe airflow limitation, and others showed no difference between CF and control subjects. Methodologic problems could explain these discrepant findings. The aim of this study was to better characterize Q and SV with exercise in CF patients with mild as well as severe airflow obstruction. Subjects included 18 CF patients with FEV1 ranging from 28 to 80% of predicted without pulmonary hypertension, and 16 matched control subjects. Cardiac output was measured at three levels of upright cycle exercise using the indirect Fick (CO2) method with blood gas sampling. Q on exercise was similar among control and CF subjects. SV was lower in CF patients, particularly those with FEV1 < or = 55% predicted, than in control subjects. Stepwise regression of SV on height, percent ideal body weight, and FEV1 showed a significant effect of relative underweight on SV. Despite this, well-nourished patients with FEV1 56 to 80% of predicted also had lower SV. As these findings were consistent across the range of severity of lung disease and age, even in the absence of malnutrition, they imply that another mechanism accounts for SV limitation during exercise in CF.

Does an additional source of pulmonary blood flow alter outcome after a bidirectional cavopulmonary shunt?

BACKGROUND: The bidirectional cavopulmonary shunt has become an important intermediate step in the treatment of pediatric patients with single ventricle physiology who are ultimately destined for palliative surgery. We wanted to know whether there would be risks or benefits if an additional source of pulmonary blood flow was left after a bidirectional cavopulmonary shunt. METHODS AND RESULTS: We retrospectively reviewed the medical and surgical records of all patients who underwent a bidirectional cavopulmonary shunt at the Children's Hospital of Wisconsin between January 1991 and December 1993. A total of 43 patients were identified. Anatomic diagnoses included double inlet left ventricle (14 patients), tricuspid atresia (8 patients), pulmonary atresia with intact septum (6 patients), single right ventricle (5 patients), hypoplastic left heart (3 patients), unbalanced atrioventricular septal defect (3 patients), and other complex lesions (4 patients). We then divided the patients into two groups for purposes of analysis. Group 1 had only the cavopulmonary shunt as a source of pulmonary flow (22 patients); group 2 had an additional source of pulmonary flow (21 patients). Patient age at the time of cavopulmonary shunt ranged from 6 months to 12 years, with group 1 patients being younger (31 versus 45 months, P = .05). Group 2 patients had higher postoperative central venous pressures (17.8 versus 14.1 mm Hg, P < .001) and oxygen saturations (86% versus 81%, P < .001) than did group 1 patients. There was no statistical difference between groups in the number of chest tube days or hospital days. There was 1 early death in group 1 related to severe ventricular dysfunction and 1 late death in group 2 related to sepsis. Five patients in group 2 were readmitted to the hospital for drainage of a large chylothorax compared with none in group 1 (P < .02). CONCLUSIONS: We conclude that patients with an additional source of pulmonary blood flow after bidirectional cavopulmonary shunt have higher postoperative central venous pressures, have higher oxygen saturations, and are at risk for the late development of a chylothorax.

Public awareness of the risks of drinking alcohol during pregnancy: the effects of a television campaign. Child Health Committee, Manitoba Medical Association.

OBJECTIVE: To evaluate the impact of a television public awareness campaign on knowledge of the dangers of drinking alcohol during pregnancy. DESIGN: A survey with five questions on alcohol and pregnancy and five health questions unrelated to alcohol was administered before and after the campaign. PARTICIPANTS: Three thousand women aged 15-45 years. INTERVENTION: A 30-second announcement with a message on alcohol and pregnancy was broadcast over ten weeks by five television stations in Manitoba. RESULTS: More respondents after the campaign thought that alcohol consumption in pregnancy would put the baby at risk, and attributed this information to "television". There were no differences in the responses to the five health questions unrelated to alcohol. CONCLUSIONS: An increase in awareness of the risks of drinking alcohol during pregnancy was observed after a mass media campaign.

A comparison of iohexol and diatrizoate-meglumine in children undergoing cardiac catheterization.

Iohexol (Omnipaque) and meglumine and sodium diatrizoate (Renografin-76) were compared in a double-blind, randomized study for their efficacy, safety, and hemodynamic effects as angiographic contrast agents in children. Forty-four children were randomly allocated to receive either iohexol or diatrizoate as a component of their routine or emergency cardiovascular evaluation. Following age stratification, baseline physiologic parameters were not significantly different between patients receiving either iohexol or diatrizoate. After systemic ventricular injection, iohexol produced significantly less hemodynamic alteration in systemic systolic blood pressure, systemic ventricular end-diastolic pressure, and dP/dt. Less alteration in heart rate and significantly less effect on the QT interval were seen with iohexol. Image quality was comparable, although significantly more patient mobility was associated with diatrizoate-meglumine. This study shows that iohexol, a nonionic contrast medium, causes less hemodynamic disturbance than diatrizoate-meglumine in children. Therefore, its use to be preferred in these potentially high-risk patients.

Fetal echocardiography in Manitoba: a regional perspective.

In order to investigate the impact of detailed fetal echocardiography on perinatal care at a tertiary health care centre, the records of all 29 cases referred for fetal echocardiography during the years 1987-88 were reviewed. All patients had risk factors for offspring with congenital heart disease. A family history of congenital heart disease led to fetal echocardiography in about two-thirds of the cases, while the remainder were referred on the basis of abnormal cardiac screening examinations during fetal assessment. Forty examinations were performed on patients at gestational ages of 16 to 37 weeks. Detailed fetal echocardiography did not alter the perceived severity of major structural cardiac defects previously identified by an experienced fetal assessment unit and did not change or influence intrapartum care. The value of fetal echocardiography in the diagnosis and treatment of fetal tachyarrhythmias was confirmed. Also, fetal echocardiography provided reassurance of cardiac normality in cases with familial and maternal risk factors for congenital heart disease. Fetal echocardiography appears to be an inappropriate screening tool in view of its limited availability and focus. Comprehensive fetal assessment with four chamber cardiac imaging is the appropriate first-line screening test for patients with risk factors for offspring with congenital heart disease.

Thoracic electric bioimpedance measurement of cardiac output in the newborn infant.

To evaluate thoracic electric bioimpedance as a noninvasive method for measuring cardiac output, we compared the bioimpedance measurements with those obtained by means of the thermodilution indicator cardiac output technique in seven preterm and term lambs; we also studied 17 term and preterm infants. Sixty-seven simultaneous bioimpedance and thermodilution cardiac output measurements were obtained in the animals after intravascular volume expansion (saline solution infusion) and contraction (phlebotomy). A significant correlation between the cardiac output measurements by the two methods (0.82; p less than 0.001) was observed. In neonates, the observed cardiac output was 198 +/- 46 ml/kg.min in the preterm infants and 178 +/- 46 ml/kg.min in the term infants. Extrapolating animal data to the neonates, we found the thoracic segment length recommended (the average of 29% of body length and electrode distance) to be accurate. These data indicate that bioimpedance cardiac output measurement (1) is comparable to measurement by the thermodilution indicator technique in the newborn animal and (2) may be suitable for use in infants and children.

Interventricular septal motion and left ventricular function in patients with atrial septal defect.

In order to assess whether the paradoxical motion of the interventricular septum seen in patients with atrial septal defect (ASD) is due to a true abnormality in septal contraction, eight patients with ASD (age, 1.6-17 years) and eight age-matched control patients were studied using qualitative and quantitative two-dimensional (2D) and M-mode echocardiography. 2-D-echocardiographic images recorded from the parasternal short-axis projection at the level of the papillary muscles and 2D-directed M-mode tracings at this level were obtained. Comprehensive wall motion analysis of the left ventricular (LV) endocardial and epicardial borders was performed using both fixed reference and center of mass (floating reference) models. Our results indicate that interventricular septal wall motion and function are normal in patients with ASD. The apparent "paradoxical" motion is due to excessive anterior motion of the entire left ventricle, and is present only when a fixed reference system is used to assess myocardial motion, but is not present when a center of mass (floating reference system) is employed. Left ventricular function assessed by % area and perimeter change, mean radial shortening fraction, and mean radial wall thickening (2D) as well as LV shortening fraction and septal and posterior wall thickening (M-mode) was not significantly different between the two groups. Standard M-mode tracings can therefore be used to assess LV function despite this apparent abnormal septal motion.

Critical aortic stenosis. Survival and management.

The factors associated with survival in 40 neonates (age less than 28 days) with critical aortic stenosis undergoing either open (22 patients) or closed (18 patients) transventricular aortic valvotomy were reviewed. Significant adverse correlates with survival included evidence of poor perfusion preoperatively (low pH, greater than Grade 2/6 soft ejection systolic murmur) and marked congestive heart failure (hepatomegaly, cardiomegaly, elevated left atrial pressure). Congenital mitral stenosis (anulus less than 11 mm), a small aortic anulus (less than 6.5 mm), and failure to achieve an adequate aortic orifice (greater than 6 mm), at operation were identified as factors associated with increased mortality. Initial perioperative survival was better with closed aortic valvotomy. However, there was no significant difference in overall operative survival between closed (9/18, 50%) and open (8/22, 36%) aortic valvotomy (p = 0.26). The incidence of early reoperation (less than 1 year of age) was greater in perioperative survivors undergoing closed valvotomy (7/13, 54%) rather than open valvotomy (1/10, 10%) (p less than 0.05). In conclusion, long-term survival among patients with critical neonatal aortic valve stenosis remains disturbingly low (13/40, 32%) and has not significantly improved over the past 20 years.