To study the effect of maturational geometric changes on flow characteristics in the pulmonary artery trunk, anatomically accurate, acrylic flow-through models were constructed from four flexible silicone rubber casts obtained in situ in lambs weighing 2.4, 7.8, 9.5, and 11.5 kg. A silicone rubber cast of the right heart was fabricated by injecting the superior caval vein in situ with liquid silicone rubber (Dow Corning's HS-II RTV, Midland, MI). Each cast was used as a template for a transparent acrylic mold of the pulmonary artery trunk and primary generation branches. The acrylic block was then fitted with a curved rigid Plexiglass inflow tube (to simulate the curvature of the right ventricle) just proximal to the pulmonary valve sinuses and mounted in a closed loop system driven by a variable speed pulsatile pump (to simulate physiological flow rates between 0.5 and 4.0 lmin−1) A blood analog solution of polystyrene beads (Rohm & Haas Amberlite, Philadelphia, PA) suspended in a 45% by weight glycerine solution was illuminated by a laser source (15 mwatts, Siemens, Germany) to trace the flow patterns. Two flow field planes of the main pulmonary artery trunk—one parallel, and one perpendicular, to the origins of the right and left arterial branches—were visualized and video recorded (Canon H660 8mm, Japan) for subsequent analysis. A prominent vortex, originating in the center of the main pulmonary artery and directed inferiorly toward the inner wall, was noted in the flow field plane perpendicular to the bifurcation in the 9.5 and 11.5 models. These characteristics were less developed in the 7.8 kg model and not present in the 2.4 kg model, possibly because the angle of curvature was less acute than in the larger models. In the flow field plane parallel to the bifurcation, the patterns were more complex, principally influenced by turbulence in the main pulmonary artery (which increased at higher flow rates) and the geometric changes in the branch pulmonary arteries.

Although pulmonary vascular disease occurs in association with pulmonary venous obstruction, a model of pulmonary vascular lesions in this setting in small laboratory animals has yet to be described. The objective of this study was to determine if unilateral banding of pulmonary veins in the rat would produce pulmonary vascular disease that mimicked key aspects of the human disorder. Rats were anesthetized and, after mechanical ventilation and thoracotomy, one of the four pulmonary veins was banded to reduce its external diameter by approximately 65–75% to 0.8 mm. Additional animals, sham-operated controls, were treated identically except for venous banding. Mortality did not differ between groups and was less than 20%. Eight weeks after surgical preparation, moderate pulmonary hypertension was demonstrated with a mean pressure in the pulmonary artery of 24.9 mm Hg (range 19.25 – 30.0) in the banded group versus 18.7 mm Hg (range 16.6 – 19.3) for sham-operated animals. Pulmonary cineangiography in rats with banded pulmonary veins demonstrated marked pulmonary congestion and a prolonged residence time of contrast medium in the capillary circulation of the lung region subjected to banding. Angiographically, non-banded lungs were similar to shams. Histopathology of the vein-banded region revealed venous congestion, arterialization of veins, perivenular edema, and sparse to moderate inflammation. Prominent bronchial vessels, pulmonary arterial medial and occasional intimal thickening, and periarterial inflammation were also observed in banded regions. Similar inflammation around pulmonary arterial and pulmonary venous vessels was noted in contralateral lung lobes but not in sham-operated control rats. Morphometric evaluation of all muscular pulmonary arteries from 50–200μ external diameter accompanying airways to the level of terminal and respiratory bronchioles indicated that the medial area in lung regions subjected to venous banding was over three times greater than in shams. Pulmonary arteries from the contralateral, unbanded lungs of treated animals also exhibited a two-fold increase in medial area. These findings indicate that a modest degree of pulmonary venous banding in rats produces congestion and causes alterations in lung vessels which are reminiscent of those observed in humans with pulmonary venous outflow obstruction. Such a model in a cost-effective laboratory animal should be useful for delineating the specific mechanisms underlying these alterations.

The prognosis for the fetus or neonate with asplenia syndrome is unknown as population-based data are unavailable. Factors influencing survival in this syndrome were, therefore, assessed for the province of British Columbia by retrospective review of all cases diagnosed between 1970 and 1990. Particular attention was paid to the prognostic influence of palliative surgery, sepsis, extracardiac malformations, gastrointestinal disease, arrhythmias and sudden death. We identified 43 cases of asplenia syndrome, of which 40 were live-born (incidence 1/22,000 live‐births). Only one spontaneous death was noted during fetal life amongst approximately 5,000 fetal autopsies. Five cases had been diagnosed by fetal echocardiography, two of these pregnancies being terminated. Of the live-born infants, 28 (70%) underwent active management of their cardiac anomalies and of these, 14 are alive. Since 1980, 26 systemic-to‐pulmonary shunts have been constructed in 17 children with two operative deaths. Three children have had successful Fontan or bidirectional Glenn procedures. Systemic sepsis occurred in three children with no deaths. Three neonates underwent surgery for obstruction of the upper gastrointestinal tract without complication. Late sudden death occurred in four children with systemic-to-pulmonary shunts, none of whom had documented arrhythmias. Major extracardiac malformations were present in nine cases (21%), these contributing to death in two. Overall survival for all live-born infants is 35%. Sepsis and palliative surgery are no longer the major causes of death in asplenia syndrome, the current challenges being prevention of sudden death and the complexity of surgical repair of the cardiac malformations.

The incidence and spectrum of extracardiac malformations in congenital asplenia syndrome were determined by review of43 cases (40 live-births) identified in the province of British Columbia over a 21 year period. Major extracardiac anomalies (excluding those of abnormal arrangement of the organs) were identified in nine cases (21%), and minor anomalies were present in an additional twelve infants (28%). Extracardiac anomalies were associated with one spontaneous stillbirth, one termination of pregnancy, and two early neonatal deaths. In an additional four newborns, they contributed to a decision not to palliate the complex cardiac anomalies. Gastrointestinal malformations led to neonatal intestinal obstruction in four infants. Of the 14 surviving children, one is severely handicapped due to a congenital anomaly of the central nervous system. The clinical significance of extracardiac malformations and their developmental implications are discussed.

The incidence of spontaneous closure of uncomplicated defects of the oval fossa was determined in cohort of 498 children. Surgical repair was accomplished in 428 at a median age of 4.5 years. Of the 70 who did not undergo surgery, 20 showed spontaneous closure or a decrease in size of the defect. The defect was unchanged in the other 50. The age at diagnosis, pulmonary-to-systemic flow ratio and size of the defect were not statistically significantly different in the changed and unchanged groups, and there was no difference in prevalence of symptoms, the triad of systolic and diastolic murmurs and abnormal splitting of the second sound, or of right ventricular enlargement by echocardiography. The rate of spontaneous diminution in size or actual closure of a defect in this series was 4%, and no clinical predictor of change in the size of a defect was identified. Thus, delay in repair of a large flow atrial septal defect in the hope of spontaneous closure is not justified, whether or not symptoms are present.

The annual and seasonal distribution of the prevalence of congenital cardiac malformations was calculated in 664,218 infants born from 1977 to 1984 in Bohemia (population of 6.3 million). All children who died were autopsied and those confirmed as having a malformation of the heart were included in our series. In total, 4,409 infants (6.64/1,000 live-births) were born with a cardiac defect. Annual variations were insignificant. The prevalence rate of cardiac malformations at birth was highest in October and lowest in December, June and July. It was not modified by differences in the birthrate. The peak of the prevalence coincided with the epidemics of influenza in early pregnancy. A nonuniform seasonal variation was found in individual forms of congenital malformations of the heart, indicating their possible etiological heterogeneity.

Magnetic resonance imaging was performed in 26 patients who underwent a modified Fontan procedure. Their age ranged from 1.8 to 31 years with a mean of 12.2 years. A valveless anastomosis was performed between the right atrium and the rudimentary right ventricle in 12 patients and between the right atrium and the pulmonary arteries in 10 patients. A cavopulmonary connection was established in the remaining four patients. Spin echo and gradient echo scans of the heart were performed in orthogonal and angulated projections. The cross-sectional area of the atrioventricular, atriopulmonary or cavopulmonary anastomoses was measured using diameters in two orthogonal imaging planes. Recordings were examined for the presence of right atrial thrombosis, the site of drainage of the coronary sinus, compression of the pulmonary veins, as well as for the presence and extent of pericardial effusions. Cine recordings were used for the assessment of the pattern of flow within the right atrium. The cross-sectional area of the anastomoses could be determined in 24 of 26 patients. This was not statistically different between patients with different surgical procedures. Patients with a cavopulmonary connection, however, tended to have a smaller anastomosis (mean 1.4 cm2/m2 BSA, S.D. 0.62) than patients with atrioventricular (mean 3.0 cm2/m2, S.D. 2.1) or atriopulmonary (2.4 cm2/m2, S.D. 1.1) connections. When compared to normal values for the size of the tricuspid valve, the size of the anastomosis was within the normal range in only four patients, it was larger in one and smaller in 19 patients. There were signs of right atrial thromboses in the scans in eight of 26 patients, as observed by two independent investigators. The site of drainage of the coronary sinus was imaged in 20 of 26 patients and was in accordance with the description of surgical procedure in eight. Compression of the right pulmonary veins by an enlarged right atrium was present in seven patients. This was severe in two children. Presence and extent of pericardial effusions could be adequately assessed in 11 of26 patients. Systolic regurgitation from the rudimentary right ventricle into the right atrium was shown in eight of 12 patients with an atrioventricular valveless anastomosis. Cine recordings revealed slow forward flow from the right atrium into the pulmonary arteries in seven of 22 patients, and there was a markedly altered pattern of intraatrial flow in two patients with anomalous systemic venous connections. Magnetic resonance imaging allows adequate examination of right atrial anatomy, determination of the size of the anastomosis with the pulmonary arteries, and semiquantitative assessment of pulmonary blood flow in the majority of patients after a modified Fontan procedure.

M-mode echocardiograms were recorded from 298 healthy adolescents between 10 and 16 years of age. Nineteen measured and 10 calculated parameters were correlated with the subjects’ gender and sexual maturity rating. Significant (p<0.05) differences by gender were demonstrated for 21 of 29 parameters. Sexual maturity rating had a significant effect on four of 29 parameters for boys and on five of 29 parameters for girls, when controlling for body surface area. Fourteen of 29 parameters in boys and three of 29 parameters in girls showed a significant effect of sexual maturity rating when controlling for age. The male adolescent growth spurt in lean body mass is paralleled by a similar growth spurt in left ventricular volume.

Between December 1982 and April 1991, balloon atrial septostomy was performed in the intensive care unit under echocardiographic control in 60 neonates. Of the patients, 58 had complete transposition. Two patients had double outlet right ventricle with a sub-pulmonary ventricular septal defect. Associated lesions included a patent arterial duct in 19 patients, ventricular septal defect in nine, obstruction of the left ventricular outflow tract in six, aortic coarctation in two and tricuspid atresia in one. The mean age at septostomy was four days (range 4 hours - 25 days) and the mean weight 3.19 kg (range 1.17–4.25 kg). In 39 (65%) patients, an infusion of prostaglandin was in progress prior to the septostomy and 22 (37%) were being ventilated. Standard subcostal four-chamber echocardiographic views were used to show the atrial septum and to guide the catheter used for septostomy. Venous access was obtained via the femoral vein in 43 (by percutaneous puncture in 40 and by cutdown in three) and the umbilical vein in 17. Transient atrial arrhythmias were common during the septostomy but no acute hemodynamic disturbances or deaths occurred during the procedure. The size of the atrial septal defect as measured by echocardiography after the septostomy ranged from three to 12 mm in diameter. In only one patient was this inadequate. Three (5%) patients died between two and 10 days after the septostomy, two due to necrotizing enterocolitis and one from persistent hypoxemia. One patient had a cerebral thrombosis and convulsions immediately after the septostomy but made a good neurological recovery. Corrective surgery was performed in 52 (86.6%), two (3.3%) had palliative surgery and two were considered unsuitable for total correction, of whom one has died. One patient died whilst awaiting correction. We conclude that balloon atrial septostomy using echocardiographic guidance can be safely and effectively performed in the intensive care unit.

A common systolic ejection murmur of the neonate has been attributed to physiologic peripheral pulmonic stenosis. We investigated this auscultatory finding using duplex pulsed Doppler. Three groups of normal fuliterm neonates less than one week old were studied—10 without murmurs, 10 with grade 1/6 murmurs and nine with at least grade 2/6 murmurs. We measured the anatomical size and peak flow velocities in the main pulmonary artery and left and right branches, the peak velocity in the right ventricular outflow tract, and the bifurcation angle. Flow gradients were calculated as 4 (Vmax)2 Groups were compared by t-tests. A loud peripheral pulmonic stenosis murmur was associated with increased pulmonary artery velocities, with left pulmonary artery velocity the most discriminating variable (1.3 ± 0.29 vs 0.94 ± 0.19 m/s; p ≤ 0.05). Although the peak gradient never exceeded 12 mmHg, there was an increased gradient in the loud murmur group (8.7 ± 2.6 vs 5.7 ± 2.2 mmHg; p ≤ 0.05) which may even be underestimated by the lack of angle correction. The left pulmonary artery diameter was also larger in the loud murmur group, but there were no other anatomic or volumetric flow differences between groups. The soft murmur group could not be separated from normals. We conclude that Doppler techniques can confirm the physiologic basis of peripheral pulmonic stenosis murmurs.

Noninvasive translumbar renal artery Doppler blood flow patterns were obtained in 20 normal children, 11 with successfully repaired coarctation, and eight with native or restenosed coarctation. Native or restenosed lesions result in decreased relative systolic velocity and prolonged acceleration time. After successful surgery, the renal flow returns to near normal. This technique may provide a useful tool to explore and predict hemodynamic and renal physiologic changes, and follow the course of therapy.

Tricuspid valve endocarditis on a normal valve has been rarely documented in children. In all five previous cases the infecting organism was Staphylococcus aureus. We report five infants and children with tricuspid valve endocarditis, whose ages ranged from four months to four years. In all of them large vegetations were identified by two-dimensional echocardiography. Positive blood cultures were found in four of five patients. Staphylococcus aureus, Corynebacterium species, Haemophilus influenzae and Candida albicans were the respective isolates. There were three deaths, all relatively sudden, 10–33 days after commencement of antibiotic therapy. At the only post mortem carried out in the patient with Candida albicans endocarditis and Down syndrome, there were two large fungating masses straddling the tricuspid valve. They appeared to have obstructed the circulation. Microscopic examination of a lymph node and the thymus showed features consistent with an immune deficiency syndrome. One child has been lost to follow-up. In the remaining survivor, progressively severe tricuspid regurgitation with congestive cardiac failure, necessitated open heart surgery 13 months later. A homograft replacement of the destroyed septal leaflet was carried out. Tricuspid valve endocarditis in an infant or child is a serious and potentially lethal condition. Early surgical intervention to remove large obstructive vegetations appears to be warranted.

We studied the cardiac conduction system in a case of Hurler syndrome. There was dense fibrosis of the supporting matrix of the sinus node and accumulation of mucopolysaccharide in the nodal cells. The bundle branches showed prominent hydropic degeneration, being encased and punctuated by dense fibrous tissue. These changes in the conduction system may predispose to the development of arrhythmias, accounting for the sudden deaths in Hurler syndrome.

A 21-year-old woman with tetralogy of Fallot, who had undergone a right Blalock-Taussig shunt at one year of age, developed endocarditis of the aortic valve. Septic thrombosis of the right pulmonary artery was diagnosed by intraoperative transesophageal echocardiography. Replacement of the aortic valve initially performed by a St. Jude Medical prosthesis, was unsuccessful due to immobilization of the valve occluder. Subsequent replacement of the St. Jude valve by a Carpentier-Edwards valve was uneventful. Thrombectomy and patch enlargement of the right pulmonary artery were also performed successfully. We suggest that the St. Jude Medical valve should be employed with caution for replacement of the aortic valve in patients with tetralogy of Fallot who have not undergone intracardiac repair. Transesophageal echocardiography is extremely useful in discovering undiagnosed associated lesion such as septic thrombosis of the pulmonary arteries.