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Biomedical subjects

N H Silverman

Publications and source records attributed to N H Silverman.

At least 91 records · Page 5Linked to original sources
PubMed1995

Diagnosis and management of fetal cardiac tumors: a multicenter experience and review of published reports.

OBJECTIVES: We sought to determine the prevalence and natural history of cardiac tumors in patients referred for fetal echocardiography. BACKGROUND: Cardiac tumors are rare; the prevalence, reported from autopsy studies of patients of all ages, varies from 0.0017% to 0.28%. Despite many case reports, the prevalence and natural history of fetal cardiac tumors are unclear. METHODS: Fourteen thousand fetal echocardiograms recorded over an 8-year period in seven centers were available for retrospective review. Medical records and echocardiograms were studied to determine the reason for referral, family history of tuberous sclerosis, prenatal and postnatal course and tumor description and type. RESULTS: Cardiac tumors were present in 19 pregnancies (0.14%). Gestational age at diagnosis ranged from 21 to 38 weeks. The most common indication for referral was a mass on an obstetric ultrasound study. The tumors were singular in 10 patients and multiple in 9. Tumor size ranged from 0.4 x 0.4 to 3.5 x 4 cm, and the majority of tumors were not hemodynamically significant. There were 17 patients with rhabdomyomas, 1 with a fibroma and 1 with an atrial hemangioma. Tuberous sclerosis complex was diagnosed in 10 patients. Partial or complete tumor regression was seen in eight patients; tumors were unchanged in five; and three required operation. CONCLUSIONS: Fetal cardiac tumors, a rare condition, are often benign. The majority of tumors are rhabdomyomas, but not all fetuses with rhabdomyoma have tuberous sclerosis.

Female↗
PubMed1994

Antenatal diagnosis of coarctation of the aorta: a multicenter experience.

OBJECTIVES: The purpose of this study was to test observations that might aid prenatal prediction of the presence of coarctation of the aorta in newborn infants with and without other forms of heart disease. BACKGROUND: Previous reports have suggested that abnormal growth of the aortic arch in utero may be identifiable as a marker for the diagnosis of coarctation. METHODS: We reviewed the prenatal echocardiograms and postnatal outcome of 20 infants (gestational age at initial study 18 to 36 weeks) with coarctation of the aorta established postnatally, to identify echocardiographic findings that would most facilitate the prenatal diagnosis of coarctation. Associated cardiac lesions included double-inlet left ventricle anatomy (n = 5), double-outlet right ventricle (n = 4), abnormal aortic valve (n = 5), unbalanced atrioventricular canal (n = 3), and membranous ventricular septal defect (n = 1). Chromosomal abnormalities included XO karyotype (n = 1), trisomy 18 (n = 1), and trisomy 21 (n = 1). RESULTS: Hypoplasia determined by measurement of the distal aortic arch was the most frequently observed finding among the fetuses with coarctation. In 12 of 15 fetuses with a well visualized transverse arch at initial prenatal study, the diameter of the transverse arch was < or = 3rd percentile for gestational age as compared with that in a normal group of fetuses. Ten of 10 fetuses with adequate images of the isthmus had isthmus hypoplasia at prenatal study with a diameter < or = 3rd percentile for gestational age. On serial study in six of seven, including three fetuses with normal distal arch measurements at initial study, the distal arch became progressively more hypoplastic for gestational age. In three there was no growth of the transverse arch or isthmus on serial study, and in three there was reversal of flow from antegrade to retrograde through the distal arch. CONCLUSIONS: In our study, quantitative hypoplasia of the isthmus and transverse arch was the most consistent observation and therefore the most definitive antenatal sign of postnatal coarctation. The potential for progression of distal arch hypoplasia necessitates serial study in fetuses with associated cardiac and noncardiac lesions.

Aorta, Thoracic↗
PubMed1993

Reconstruction of hypoplastic aortic arch and coarctation in a 720-gram premature infant.

The case of a 720-g infant born at 29 weeks of gestation who underwent successful surgical correction of a hypoplastic aortic arch and aortic coarctation is presented. The infant was initially brought to surgery with an echocardiographic diagnosis of patent ductus arteriosus with left to right shunt unresponsive to indomethacin therapy. The correct diagnosis of hypoplastic aortic arch and severe coarctation with ductal dependent blood flow to the lower body was made intraoperatively. This case illustrates the danger of limited diagnostic testing in premature infants assumed to have isolated patent ductus arteriosus, and also that these small infants can undergo successful surgical repair of complex aortic arch lesions.

Aorta, Thoracic↗
PubMed1993

Accuracy of right ventricular output estimated by Doppler echocardiography in the sheep fetus.

OBJECTIVE: Our goal was to determine whether Doppler ultrasonographic estimation of fetal right ventricular output was accurate enough to evaluate fetal cardiac performance before the technique can be applied with confidence to the human fetus. The accuracy of this method has not been validated experimentally. STUDY DESIGN: We compared the right ventricular output measured by Doppler echocardiography with that determined from a transit-time ultrasonic flowmeter placed around the fetal pulmonary trunk and to that determined by microsphere technique. We obtained 72 Doppler flow measurements and 16 microsphere flow measurements in six fetuses. RESULTS: There was a fair correlation between cardiac output estimated by Doppler echocardiography performed transabdominally and that determined by a transit-time flowmeter (r = 0.76). The correlation was excellent when Doppler echocardiography was performed by the trans-uterine approach (r = 0.94). There was also an excellent correlation between right ventricular output determined by a transit-time flowmeter and that by microsphere technique (r = 0.94). CONCLUSION: Doppler echocardiographic estimation of fetal right ventricular cardiac output is thus feasible and accurate.

Animals↗
PubMed1993

Cardiac ultrasonography in structural abnormalities and arrhythmias. Recognition and treatment.

Fetal cardiac ultrasonography has become an important tool in the evaluation of fetuses at risk for cardiac anomalies. It can both guide prenatal treatment and assist the management and timing of delivery. We recommend that a fetal echocardiogram be done when there is a family history of congenital heart disease; maternal disease that may affect the fetus; a history of maternal drug use, either therapeutic or illegal; evidence of other fetal abnormalities; or evidence of fetal hydrops. The optimal timing of evaluation is 18 to 22 weeks' gestation. An entire range of structural cardiac defects can be visualized prenatally, including atrioventricular septal defect, ventricular septal defect, cardiomyopathy, ventricular outlet obstruction, and complex cardiac defects. The outcome for a fetus with a recognized abnormality is unfavourable, with less than 50% surviving the neonatal period. Fetal cardiac arrhythmias are also a common occurrence, 15% in the series described here. Premature atrial or ventricular contractions are most commonly seen and usually require no treatment. Supraventricular tachycardia can result in hydrops and require in utero treatment to prevent fetal demise. Complete heart block, particularly in association with structural heart disease, has a poor prognosis for fetal survival.

Arrhythmias, Cardiac↗
PubMed1992

Cardiac dimensions determined by cross-sectional echocardiography in the normal human fetus from 18 weeks to term.

Assessment of cardiac dimensions of the chambers, great arteries and veins in the human fetus is important to distinguish abnormal dimensions from normal. This study establishes normal values based on cross-sectional echocardiographic measurements over the gestational period where these measurements may be clinically useful. Ventricular and atrial dimensions were measured from the 4-chamber view, the short-axis dimension immediately below the mitral and tricuspid valve leaflets in diastole, and the long axis from the closed apposed atrioventricular valves to their respective apices. The ventricular walls and septum were measured at the level at which cavity dimensions in diastole were measured, defining both the left and right ventricular wall thickness, as well as that of the ventricular septum. Furthermore, the long axis of the right and left atria was measured from the center of the apposed atrioventricular valve leaflets to the posterior atrial wall, and the sizes of the atrial chambers were defined using their widths at the prospective broadest points through the area of foramen ovale. From a variety of views, diameters were measured at maximal expansion of the main, left and right pulmonary arteries, the ductus arteriosus, and the superior and inferior venae cavae. The data were evaluated longitudinally from 18 weeks to term, and regression analysis was performed using the best fit of a linear or polynomial equation. The data provide a means for evaluating the normal sizes and dimensions of the fetal heart chambers, as well as the thickness of the ventricular walls and septum.

Aorta↗
PubMed1992

Changes of right ventricular size and function in neonates after valvotomy for pulmonary atresia or critical pulmonary stenosis and intact ventricular septum.

Right ventricular end-diastolic and stroke volumes were calculated from orthogonal subcostal echocardiographic images in 24 neonates (mean weight +/- SD 3.4 +/- 0.4 kg) with pulmonary atresia (n = 18) or critical pulmonary stenosis (n = 6) and intact ventricular septum before and at an average of 5 days and then 19 days after pulmonary valvotomy. The preoperative echocardiographic volume determinations were compared with the respective angiographic determinations. In addition, the endocardial area outlines of the left and right ventricles were obtained by planimetry from an end-diastolic frame taken in the apical four-chamber view. End-diastolic and stroke volumes calculated by the echocardiographic method (y) correlated closely with those calculated by the angiographic method (x); the regression equations were y = 1.02 x -0.13 (r = 0.95, SEE +/- 0.45 ml) and y = 1.16 x -0.15 (r = 0.89, SEE +/- 0.38 ml), respectively. All except one infant had right ventricular hypoplasia before valvotomy with an end-diastolic volume of 16.6 +/- 6.4 ml/m2 (44.5 +/- 17.3% of normal). Right to left ventricular area ratio was 0.56 +/- 0.09 (normal 0.95). Five days after valvotomy, right ventricular end-diastolic volume decreased to 10.6 +/- 4.6 ml/m2 (p less than 0.05) and stroke volume decreased from 8.3 +/- 3.5 to 5.5 +/- 2.8 ml/m2 (p less than 0.05). Nineteen days after valvotomy, right ventricular end-diastolic volume and right to left ventricular area ratio had increased to their respective preoperative values; right ventricular stroke volume had increased further to 10.4 +/- 3.9 ml/m2 (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Abnormalities, Multiple↗
PubMed1992

Intraoperative echocardiography for evaluation of congenital heart defects in infants and children.

To determine the accuracy, utility, and limitations of intraoperative transesophageal echocardiography (TEE) in infants and children, we performed prebypass and postbypass TEE in 90 children undergoing surgical repair of congenital heart lesions, comparing the results to those obtained using intraoperative epicardial echocardiography and pre- and postoperative precordial echocardiography. Patients ranged in age from 4 days to 21 yr (mean 4.1 yr) and in weight from 3 to 68 kg (mean 15.4 kg). Prebypass, we obtained high-quality, two-dimensional TEE images in 86 patients, with correction of the preoperative precordial diagnosis in 3 and confirmation of the preoperative diagnosis in the rest. Adequate epicardial images were obtained in 78 patients, with confirmation of the preoperative diagnosis in all. Shunt lesions that were well delineated prebypass by both TEE and epicardial imaging included interatrial, interventricular, and atrioventricular septal defect lesions. TEE failed to detect the exact size and location of lesions involving the right ventricular outflow tract, i.e., doubly committed subarterial (supracristal) ventricular septal defects. Regurgitant lesions (n = 30) were identified and their severity evaluated in all patients by both TEE and epicardial imaging. Obstructive lesions (n = 33), excluding those involving the right ventricular outflow tract, were well defined by both echocardiographic approaches. Postbypass, we obtained high-quality, two-dimensional, color and Doppler TEE images in 86 patients and epicardial images in 78 patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

Evaluation of changes in umbilical blood flow in the fetal lamb by Doppler waveform analysis.

Doppler velocity waveform analysis from descending aortic and umbilical artery signals was performed in 14 instrumented fetal lambs when umbilical blood flow was altered acutely. Blood flow was increased and reduced (by cord occlusion or placental embolization) and ranged 14% to 168% and 8% to 132% from baseline values in the descending aorta and the umbilical artery, respectively. When flow was severely reduced (less than 50% of baseline value), mean placental resistance increased almost fourfold and mean heart rate fell by 30% from baseline levels. There were only weak correlations between Doppler waveform indices and actual flow, which were usually not significantly different from the correlations between Doppler indices and actual heart rate. With both cord occlusion and placental embolization, significant changes of index values from baseline values were seen only when flow was severely reduced. We conclude that Doppler waveform analysis is not sensitive enough to detect acute mild to moderate reductions in placental flow. Increased index values with severely reduced flow may be explained in part by the concomitant fall in heart rate.

Animals↗
PubMed1991

Intraoperative transesophageal echocardiography of atrioventricular septal defect.

To determine the accuracy and utility of single-plane transesophageal echocardiography in analyzing atrioventricular (AV) septal defect, intraoperative transesophageal echocardiography was performed before and after institution of cardiopulmonary bypass in 16 patients (age 24 days to 14 years, weight 3 to 47 kg). Prebypass transesophageal echocardiography (including two-dimensional echocardiography, Doppler color flow mapping and pulsed wave Doppler ultrasound) correctly diagnosed divided AV valve, common AV valve and unbalanced AV valve, as well as atrial or ventricular septal defect, or both, in all cases. It correctly analyzed AV valve regurgitation in all 10 patients with right and all 14 with left AV valve regurgitation and correctly analyzed 30 of 33 additional cardiac anomalies. Transesophageal echocardiography was able to detect the absence of normal pulmonary venous connections but failed to demonstrate all of the complex anomalous pulmonary venous connections in three patients with atrial isomerism. Postbypass transesophageal echocardiography documented the absence of a significant residual shunt in 11 of 11 patients undergoing corrective surgery and verified residual AV valve regurgitation in 7 of 9 patients with tricuspid regurgitation and 11 of 13 with mitral regurgitation. Transesophageal echocardiographic information that altered or refined the surgical treatment was obtained in 5 (31%) of 16 patients. Epicardial and transesophageal echocardiography results were concordant in all 13 patients in whom both were performed. Transesophageal echocardiography provides useful and accurate imaging of the important two-dimensional, pulsed wave Doppler ultrasound and Doppler color flow mapping features in AV septal defect.

Adolescent↗
PubMed1991

Perinatal outcome of fetal complete atrioventricular block: a multicenter experience.

The clinical course and outcome of 55 fetuses with complete atrioventricular (AV) block detected prenatally were studied to identify factors that affect the natural history of this lesion. In 29 fetuses (53%) complete AV block was associated with complex structural heart defects, usually left atrial isomerism (n = 17) or discordant AV connection (n = 7). The other 26 fetuses had normal cardiac anatomy; in 19 cases the mother had connective tissue disease or tested positive for antinuclear antibodies. Six fetuses showed progression from sinus rhythm or second degree block to complete AV block. Of the 55 pregnancies, 5 were terminated and 24 fetuses or neonates died; at the end of the neonatal period 26 fetuses were still alive. Fetal or neonatal death correlated significantly with the presence of structural heart defects (4 of 29 surviving, p less than 0.001), hydrops (0 of 22 surviving, p less than 0.001), an atrial rate less than or equal to 120 beats/min (1 of 12 surviving, p less than 0.005) or a ventricular rate less than or equal to 55 beats/min (3 of 21 surviving, p less than 0.001). Mean atrial and ventricular rates were higher in surviving than in nonsurviving fetuses (142 +/- 8 vs. 127 +/- 21 beats/min, p less than 0.002; 64 +/- 8 vs. 52 +/- 8 beats/min, p less than 0.001, respectively). A slow atrial rate, however, was frequently associated with left atrial isomerism.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac Pacing, Artificial↗
PubMed1991

Intraoperative transesophageal echocardiography of ventricular septal defect.

The accuracy and limitations of intraoperative two-dimensional (2-D) and color Doppler flow mapping transesophageal echocardiography (TEE) of ventricular septal defect (VSD), before and after cardiopulmonary bypass, were analyzed in 62 children. Twenty-one patients had an isolated VSD, and 41 had a VSD plus additional cardiac anomalies. Two-dimensional and color Doppler flow mapping TEE were performed with a miniaturized 5-MHz single (transverse) plane transducer in the 51 of 62 patients weighing less than 20 kg. The remaining 11 were monitored using a single plane adult probe (n = 4) and a biplane (transverse plus longitudinal) probe (N = 7). Prebypass TEE provided a correct diagnosis in 57 of 62 cases (92%) and corrected an erroneous preoperative transthoracic echocardiographic diagnosis in three of 62 cases (5%). Single plane TEE diagnosis was erroneous in five patients: four with doubly-committed subarterial VSD and one with multiple small apical muscular defects and pulmonary hypertension. Biplane TEE (transverse longitudinal) provided clear and complete imaging of the right ventricular outflow tract in all seven cases in whom it was used. Postbypass TEE showed absence of a hemodynamically significant residual VSD in 30 of 40 patients (95%) who underwent VSD patch closure, prospectively identified two of 40 with significant residual VSD, and accurately measured the color Doppler jet width of all residual VSDs. We conclude that hemodynamically significant VSDs can be identified immediately after cardiopulmonary bypass based on the width of the residual VSD color Doppler flow map jet. Therefore, 2-D and color Doppler flow mapping TEE provide an accurate diagnosis in most cases of VSD but may miss doubly-committed subarterial and apical muscular VSD unless biplane TEE is used.

Adolescent↗
PubMed1991

Doppler echocardiographic assessment of fetal descending aortic and umbilical blood flows. Validation studies in fetal lambs.

BACKGROUND: Doppler ultrasound has been used to assess abdominal aortic and umbilical blood flows in the human fetus, but the accuracy of this approach has not been demonstrated in an animal model. METHODS AND RESULTS: We compared abdominal aortic and umbilical blood flows determined by Doppler echocardiography in 12 fetal lambs with invasive flow measurements using radionuclide-labeled microspheres and electromagnetic flow transducers. We varied fetal blood flow from 100 to 950 ml/min in the abdominal aorta and from 130 to 610 ml/min in the umbilical vein. Invasive and Doppler echocardiographic flow measurements correlated well at both sites (y = 68 + 1.02x, r = 0.94, and y = 33 + 1.1x, r = 0.91, respectively). A slight overestimation of flow using the Doppler method may require a correction factor to assess actual flow. The degree of overestimation was not systematically related to measurements taken in smaller vessels or at larger angles of incidence. CONCLUSIONS: The present study demonstrates that determination of abdominal aortic and umbilical venous flows by echocardiography and pulsed Doppler ultrasound is feasible. Doppler measurements appear to be suited to serial comparison of actual flow.

Animals↗
PubMed1990

Congenitally unguarded tricuspid orifice: its differentiation from Ebstein's malformation in association with pulmonary atresia and intact ventricular septum.

Dysplasia of the leaflets is a well-known integral part of Ebstein's malformation. It is less well-recognized that occasionally the septal leaflet may be completely absent and not simply displaced from its usual annular attachment. This may make it difficult to differentiate by echocardiography between Ebstein's malformation and the rare lesion in which the tricuspid orifice is completely devoid of leaflet tissue ("congenitally unguarded orifice"). A neonatal case is described in which a partially unguarded orifice was present in association with pulmonary atresia and intact ventricular septum but misdiagnosed as Ebstein's malformation. In addition we reviewed the morphologic features of all 46 cases of pulmonary atresia and intact septum in the Cardiopathological Collection of the Children's Hospital of Pittsburgh: 17 also had Ebstein's malformation, while three had a congenitally unguarded tricuspid orifice. We found that the differential diagnosis occurred when the right ventricle was dilated rather than being a hypoplastic cavity, as was a feature of all the cases with unguarded orifice and five of those with Ebstein's malformation. The difference between the lesions is best demonstrated by examining the mural leaflet of the valve, which is absent when the orifice is unguarded but displaced in association with Ebstein's malformation. This feature should be recognizable by cross-sectional echocardiography. We have confirmed previous studies that dilatation of the chambers of the right heart indicates a very poor prognosis in cases with pulmonary atresia and an intact ventricular septum.

Diagnosis, Differential↗
PubMed1990

Death due to high-output cardiac failure in fetal sacrococcygeal teratoma.

Fetal sacrococcygeal teratoma (SCT) is being recognized with increasing frequency. Placentomegaly and hydrops fetalis are preterminal events, and it has been suggested that fetal death may be due to high-output cardiac failure from arteriovenous shunting through the tumor. We had a chance to examine this hypothesis when a 21-week fetus presented with a huge sacrococcygeal teratoma. There were marked placentomegaly, cardiomegaly, hyperdynamic ventricles, and a pericardial effusion. Doppler studies showed tremendous flow through the SCT with extreme enlargement of the inferior vena cava, consistent with congestive heart failure from increased flow through the tumor. Hydrops developed, and the fetus was delivered because of placental abruption. This case provides supportive evidence that the teratoma acts as a large arteriovenous shunt, causing high-output cardiac failure. We have now collected 18 more cases of sacrococcygeal teratoma diagnosed in utero. Of the total 45 cases of fetal SCT, 9 had placentomegaly and/or fetal hydrops and all 9 fetuses died in utero or shortly after birth. We conclude that the only hope for survival in these severely affected fetuses is to reduce blood flow to the tumor before birth.

Cardiac Output↗
PubMed1990

Intraoperative echocardiography in infants and children with congenital cardiac shunt lesions: transesophageal versus epicardial echocardiography.

To determine the utility and limitations of intraoperative transesophageal echocardiography in infants and children with congenital intracardiac shunts, intraoperative transesophageal (n = 50) and epicardial (n = 49) echocardiograms were performed before and after cardiopulmonary bypass in children from 4 days to 16 years old and 3 to 45 kg in body weight. A miniaturized transesophageal probe (6.9 mm maximal diameter) was used in 36 patients weighting less than or equal to 20 kg. Epicardial imaging was performed with a 5 MHz precordial probe. The intraoperative transesophageal echocardiographic findings before and after cardiopulmonary bypass were correct and complete in 94% of patients. Transesophageal echocardiography correctly identified atrial septal defects, most types of ventricular septal defects, anomalous pulmonary veins, atrioventricular septal defects, tetralogy of Fallot, truncus arteriosus and double inlet ventricles. It failed to provide a correct diagnosis in only three patients, all of whom had doubly committed subarterial ventricular septal defects. Epicardial echocardiography identified all cases that had a doubly committed subarterial ventricular septal defect. A correct and complete intraoperative diagnosis was obtained with the use of epicardial imaging in 92% before and after cardiopulmonary bypass, but this technique required interruption of surgery and could not be completed in three patients because of induced arrhythmias and hypotension. These results demonstrated that intraoperative transesophageal echocardiography consistently defined important morphologic, color and pulsed Doppler ultrasound features of most congenital shunt lesions. Lesions that involved the right ventricular outflow tract are sometimes difficult to image with uniplane transesophageal echocardiography. There were no complications in any of the 50 subjects.

Cardiopulmonary Bypass↗
PubMed1990

Malaligned outlet septum with subpulmonary ventricular septal defect and abnormal ventriculoarterial connection: a morphologic spectrum defined echocardiographically.

A retrospective analysis of 62 echocardiograms from 22 patients with malaligned outlet septum, subpulmonary ventricular septal defect and abnormal ventriculoarterial (VA) connection was performed and the results were confirmed by intraoperative inspection, cardiac catheterization and angiography, or pathologic specimen analysis in 21 of the 22 patients. The purpose of this study was to determine the relative incidence of the primary morphologic features; the correlation between the presence or absence of mitral valve to pulmonary valve fibrous continuity and the type of VA connection; the types and incidence of additional cardiovascular anomalies; and the correlation between the determination of the VA connection by echocardiography versus that ascertained at intraoperative and autopsy inspection. A spectrum of VA connections was found, ranging from double outlet right ventricle (23%) at one extreme, through an intermediate type (64%) in which the pulmonary artery was overriding the ventricular septum, thereby having no consistent and predominant connection to either ventricle, to a discordant VA connection (13%) at the opposite end of the spectrum. All three types of VA connection occurred whether or not there was mitral valve to pulmonary valve fibrous continuity. Additional cardiovascular anomalies were present in 95% of patients, the most common being aortic arch obstructive lesions in 59%, anomalous attachments of the atrioventricular valve tension apparatus in 55% and subaortic stenosis in 50%. A method of echocardiographic determination of the VA connection that correlated with that determined intraoperatively and from pathologic specimen analysis is described.

Abnormalities, Multiple↗