Management of hypoplastic left heart syndrome in a consortium of university hospitals.

To determine current management of hypoplastic left heart syndrome, we utilized the discharge database of the University Hospital Consortium and obtained data on the surgical procedures, length of stay, hospital charges, and outcome for 636 neonates with this condition admitted to 40 member institutions from 1989 to 1993. Of the 636 patients, 95 (15%) were discharged without surgical intervention. A Norwood operation was performed in 222 (53% mortality) and transplantation in 40 (42% mortality). Median length of stay and hospital charges were 17 days and $57,418 for the Norwood procedure and 47 days and $126,695 for transplantation.

Noninvasive assessment of myocardial contractility, preload, and afterload in healthy newborn infants.

Assessment of ventricular contractility in the newborn infant using standard echocardiographic indexes can result in error due to the unique physiologic state that exists in the neonatal period. It has been suggested from animal and human studies that maturational alterations in contractility occur with birth and continue throughout infancy. To further investigate these developmental changes, 41 newborn infants aged 3 to 10 days and 37 children aged 3 to 18 years were evaluated with 2-dimensional and M-mode echocardiography. The rate-corrected velocity of circumferential fiber shortening (VCFc)-end-systolic wall stress (ESWS) relation was used as a load-independent estimate of contractility. Preload, afterload, and ventricular mass were also measured. Despite similar shortening fractions, the infant group had significantly higher mean VCFc and lower ESWS than the older age group (1.28 vs 1.08 circ/s and 30.2 vs 37.3 gm/m2, respectively). An inverse linear relation between VCFc and ESWS was found in both age groups. The y-intercept was higher in the infant group (p < 0.01), and the slope of the mean regression line was steeper than in the older children (p < 0.01). Ventricular mass in relation to body surface area increased with age. We conclude that (1) newborn infants have a higher basal contractile state that cannot be accounted for by lower afterload, (2) myocardial performance is more sensitive to afterload in the immature heart, and (3) shortening fraction may underestimate ventricular function in the newborn.

Application of information theory to decision analysis in potentially prostaglandin-responsive neonates.

To define settings in which use of prostaglandin E1 before transfer from a community hospital to a tertiary care center benefits neonates with possible heart disease, information theory was used to predict the probability of a favorable response to prostaglandin therapy from the limited information of clinical variables. Records of 250 patients, newborn to 7 days old, with suspected heart disease were reviewed to assess six clinical variables (cyanosis, respiratory distress, heart murmur, pulse contour, hepatomegaly and prematurity). According to the anatomic and hemodynamic cardiovascular condition, each case was categorized as to whether a favorable response to prostaglandin E1 could be anticipated. Information content of each clinical variable with respect to prostaglandin responsiveness was determined, and patients were classified according to the most informative clinical variable. Stepwise extraction of information proceeded until remaining clinical variables added no significant information. Bayes' rule gave estimates of probability of prostaglandin-responsive defect in final subgroups for use in decision analysis. Cyanosis, murmur, small volume pulses and prematurity gave information about prostaglandin-responsive defects. Decision analysis indicated that frequency of poor outcome is minimized by early prostaglandin treatment of cyanotic term infants with a murmur or poor pulses, regardless of how ill they appear, and by treating any critically ill term newborn who has either cyanosis or poor pulses. Acyanotic patients with normal pulses are best untreated with prostaglandin until after definitive diagnosis is made. Advantage to either course was not seen in some small subgroups. Information theory with decision analysis is a rigorous approach to identify relevant clinical variables and define their roles in critical decisions in pediatric cardiology.

Assessment of the ductus arteriosus in preterm infants utilizing suprasternal two-dimensional/Doppler echocardiography.

Evaluation for patent ductus arteriosus by both Doppler examination and direct two-dimensional echocardiographic visualization has been reported in infants and children. However, visualization of a patent ductus arteriosus in preterm infants with lung disease has been difficult. Using a recently developed 7.5 MHz mechanical scanner with interfaced two-dimensional directed pulsed Doppler ultrasonography, 36 examinations were performed from a suprasternal approach in 27 patients (age range 1 day to 3 months, mean 18 days; weight range 490 to 2,500 g, mean 1,260). Complete imaging for evaluation of patency of the ductus arteriosus was successful in 33 (92%) of 36 examinations, and imaging of the pulmonary end of the ductus arteriosus was successful in all. In 18 examinations, the ductus arteriosus was closed by both two-dimensional echocardiography and Doppler examination. In four cases the ductus arteriosus was widely patent by both two-dimensional echocardiography and Doppler examination. Eleven echocardiographic examinations revealed a narrowed ductus arteriosus, and of these, 10 (91%) showed Doppler findings of patent ductus arteriosus. It is concluded that combined two-dimensional/Doppler echocardiographic assessment allows confident detection of both a large unrestrictive and a small, stenotic patent ductus arteriosus in preterm infants with lung disease.

Echocardiographic assessment of cardiac function in infants and children.

Echocardiography has become an established technique for the assessment of cardiac function in infants and children. M-mode echocardiography provides measurements of left ventricular diameter and wall thickness and allows calculation of their rate of change during the cardiac cycle. Left and right ventricular systolic time intervals may be determined from recordings of aortic and pulmonary valve motion. Two-dimensional echocardiographic images may be utilized for the determination of left and right ventricular volume and ejection fraction. Compared with other noninvasive imaging methods, echocardiography is a rapid, safe and inexpensive technique. Moreover, future developments are likely to include improved image processing and computer analysis of two-dimensional images.

Two-dimensional echocardiographic assessment of pulmonary artery and aortic arch anatomy in cyanotic infants.

To determine the feasibility and accuracy of noninvasive assessment of pulmonary artery and aortic arch anatomy, a prospective two-dimensional echocardiographic evaluation was performed in 20 consecutive cyanotic infants before cardiac catheterization and angiography. The echocardiographic assessment was correct with the following frequency: detection of left aortic arch in 13 of 13 infants, detection of right aortic arch in 7 of 7, identification of patent ductus arteriosus in 13 of 13 (one false positive finding), identification of a right pulmonary artery in 20 of 20, identification of a left pulmonary artery in 19 of 20, identification of the confluence of the right and left pulmonary arteries in 19 of 20 and identification of a main pulmonary artery in 14 of 16 (two false positive diagnoses by echocardiography). Echocardiographic estimates of arterial diameters were slightly smaller than those obtained by angiography. Mean vessel size (echocardiographic/angiographic diameter) was as follows: transverse aortic arch 8.6/10.6 mm, main pulmonary artery 5.7/6.3 mm, right pulmonary artery 4.1/4.2 mm and left pulmonary artery 4.2/3.9 mm. It is concluded that although two-dimensional echocardiography tends to underestimate vessel size, the qualitative assessment is adequate for planning a systemic to pulmonary artery anastomosis in selected infants with cyanotic forms of congenital heart disease.

Patency of the ductus arteriosus in normal neonates: two-dimensional echocardiography versus Doppler assessment.

Two-dimensional echocardiography using a high resolution, 7.5 ,Jsz transduce was compared with Doppler echocardiography for the assessment of patency of the ductus arteriosus in normal newborn infants. Twenty-eight neonates were studied between 1 and 10 hours (mean 5.5) after birth and both examinations were possible in 27 (96%). Doppler echocardiography under two-dimensional direction indicated ductal patency in all 27 neonates. Doppler sampling in the pulmonary end of the ductus rather than the main pulmonary artery was more sensitive for detecting patency. When two-dimensional echocardiography only was used to predict patency, there was 85% sensitivity. Two-dimensional echocardiography showed no evidence of ductus arteriosus narrowing ion four neonates studied shortly after birth. In 18, the pulmonary portion of the ductus arteriosus appeared narrowed and in 8 of these, the narrowing extended toward the mid-portion of the ductus. In five others, there was only mid-ductus arteriosus narrowing. It is concluded that high resolution two-dimensional echocardiography can be used to assess ductus arteriosus morphology, but is limited in predicting ductal patency near the time of normal physiologic closure. Combined two-dimensional and Doppler echocardiography is a highly sensitive technique for detection of ductal patency when sampling is performed in the pulmonary end of the ductus arteriosus.

Two-dimensional echocardiographic assessment of the aorta in infants and children with congenital heart disease.

To determine the accuracy of two-dimensional echocardiography in the identification of congenital anomalies of the aorta, we compared two-dimensional echocardiographic with angiographic results in 261 consecutive infants and children with congenital heart disease (age 1 day to 20 years, mean 3.3 years). Two-dimensional echocardiography was performed and interpreted without knowledge of angiographic results. Complete visualization of the ascending and descending aorta and aortic arch branches was possible by two-dimensional echocardiographic examination in suprasternal, parasternal, and subcostal views of 255 patients (98%). Identification of the esophagus during swallowing aided the diagnosis of anatomic characteristics of aortic arch. One or more significant aortic arch anomalies were present on angiograms of 116 of 255 patients (46%) and were detected by two-dimensional echocardiography in 110 (sensitivity 95%, 99% specificity). Anomalies detected by two-dimensional echocardiography/angiography were ascending aorta hypoplasia in four/four, truncus arteriosus three/three, right aortic arch 31/31, anomalous subclavian artery 11/16, coarctation 27/29, and patent ductus arteriosus 53/57. We conclude that two-dimensional echocardiography can be used to determine the anatomy of the aorta in most infants and children. In selected patients, two-dimensional echocardiography may eliminate the need for angiographic examination before surgery for congenital heart disease.

Exercise assessment of sinoatrial node function following the Mustard operation.

To screen for sinoatrial node dysfunction following the Mustard procedure for transposition of the great arteries, we studied the chronotropic response to graded maximal treadmill exercise in 29 patients at mean 6.7 years after operation. Although 93% of patients had normal resting heart rate (HR), 83% demonstrated significant depression of maximum HR and/or recovery HR after termination of exercise. These findings were similarly present among a subset of 13 patients with normal exercise tolerance. Resting and exercise-induced HR in 10 patients receiving chronic digoxin therapy were no different than in the 19 patients without medication. Sixteen patients with abnormal chronotropic responses to exercise had intracardiac electrophysiologic evaluation which confirmed sinoatrial node dysfunction in nine. Abnormal HR responses did not correlate with clinical symptoms, cardiac arrhythmias, or postoperative hemodynamics. Maximal exercise testing may be a sensitive noninvasive method to identify sinoatrial node dysfunction in postoperative children.