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Biomedical subjects

N H Silverman

Publications and source records attributed to N H Silverman.

At least 109 records · Page 6Linked to original sources
PubMed1990

Echocardiographic spectrum of double inlet ventricle: evaluation of the interventricular communication.

To determine the spectrum and associated anomalies of double inlet ventricle (single ventricle), echocardiographic data of 50 patients with double inlet ventricle were reviewed and compared with the data obtained by cardiac catheterization, cardiac surgery and autopsy. Standard echocardiographic planes were used to determine the cardiac anatomy and the size of the interventricular communication. Double inlet by way of two perforate valves was found in 44 patients. In 42 of the 44 patients the dominant ventricular morphology was of the left ventricular type (double inlet left ventricle); in 13 of these 42 patients stenosis of one atrioventricular (AV) valve was found. Double inlet right ventricle and double inlet indeterminate ventricle were each found in one patient. Double inlet by way of a common AV valve was found in six patients, all of whom had atrial isomerism. The diagnosis of double inlet ventricle was accurate by two-dimensional echocardiography in all 44 patients. A restrictive interventricular communication was shown in 13 patients and a nonrestrictive communication in 17 patients by cardiac catheterization. Patients with a restrictive interventricular communication had a significantly smaller interventricular communication area normalized by the body surface area (mean +/- SD 1.21 +/- 0.53 cm2/m2) than did those with a nonrestrictive interventricular communication (2.33 +/- 0.71 cm2/m2) (p less than 0.01). Infants with an aortic anomaly had a significantly smaller interventricular communication area (1.35 +/- 0.65 cm2/m2) than did those without an aortic anomaly (2.57 +/- 0.76 cm2/m2) (p less than 0.05). Echocardiography provides an accurate noninvasive diagnosis in patients with double inlet ventricle, offering reliable information about the restrictive interventricular communication.

Adolescent↗
PubMed1990

Interventional neuroradiological management of vein of Galen malformations in the neonate.

Since 1978, the authors have seen 14 neonates with vein of Galen malformations who were born with severe congestive heart failure. The 5 infants treated before 1983 underwent craniotomy and clipping of feeding vessels; all died in the perioperative period. Since 1983, 8 neonates have been treated with combined arterial and venous interventional neuroradiological techniques; 6 infants survived. Two-dimensional echocardiography, color Doppler flow imaging, and pulsed Doppler ultrasound were used to assess blood flow within the malformation before and after staged transluminal embolic procedures were performed. The results of the diagnostic studies and the clinical status of the infants were used to evaluate the success of embolic therapy and the need for further neuroradiological intervention.

Cerebral Veins↗
PubMed1990

Serial ultrasonographic evaluation of neonatal vein of Galen malformations to assess the efficacy of interventional neuroradiological procedures.

Two-dimensional echocardiography complemented with color-flow imaging and pulsed Doppler ultrasound was used to evaluate one fetus and five neonates with a vein of Galen malformation who had severe high-output congestive heart failure and cranial bruits at birth. Intracranial blood flow through the vein of Galen malformations, cardiac status, and direction of aortic blood flow were assessed before and after staged interventional neuroradiological treatment with transarterial and transvenous embolization procedures. Color-flow imaging in each infant displayed the major vascular anatomy including feeding vessels and the patterns of filling of the vein of Galen malformations. Pulsed Doppler ultrasound performed on the descending aorta above the diaphragm showed the degree of diastolic flow reversal indicative of runoff into the vein of Galen malformations. A reduction in blood flow through the vein of Galen malformation was seen on color-flow imaging in four patients treated successfully by embolic procedures. The ratio of diastolic retrograde flow velocity in the descending aorta to systolic antegrade velocity decreased from 0.51 +/- 0.15 (mean +/- standard deviation) to 0.15 +/- 0.20 (P less than 0.05). Color-flow imaging and pulsed Doppler ultrasonography provided anatomical and pathophysiological information regarding cardiac hemodynamics and intracranial blood flow; with the patient's clinical status, these methods provided a reliable, noninvasive means to evaluate the effectiveness of therapy and the need for further treatment in neonates with vein of Galen malformations.

Cerebral Veins↗
PubMed1990

Conjoined twins: prenatal diagnosis and assessment of associated malformations.

Prenatal diagnosis of conjoined twins is difficult and was rarely accomplished prior to the advent of sonography. Early prenatal diagnosis and assessment for shared vital organs are desirable for optimal obstetrical counseling and management. The authors retrospectively reviewed prenatal findings in 14 cases of conjoined twins. Thoracoomphalopagus was the most common type of conjoining, occurring in five cases (36%). Prenatal sonography showed shared hearts in nine (64%) cases, indicating severe conjoining and negligible chance for postnatal correction. Two sets of omphalopagus conjoined twins had separate hearts; however, severe congenital heart disease was present. Early prenatal diagnosis and assessment of the degree of conjoining provided couples with the option for pregnancy termination via vaginal delivery. In this series, nine patients elected pregnancy termination prior to 24 weeks and delivered vaginally. Transvaginal ultrasound significantly improved the delineation of conjunction in two patients, and computed tomography permitted the diagnosis to be confirmed in two patients.

Diagnostic Errors↗
PubMed1990

Two-dimensional echocardiographic determination of ventricular volumes in the fetal heart. Validation studies in fetal lambs.

The determination of ventricular volumes in the fetal heart from two-dimensional echocardiography (2DE) may give a better estimate of fetal ventricular size than simple diameter measurements, but the accuracy of this method has not been established. In fetal lambs, we tested whether ventricular volume calculations from 2DE using a biplane Simpson's rule algorithm are accurate. Calculations of left and right ventricular end-diastolic volumes from 2DE were compared with cast volumes of these ventricles. Also, at different levels of left atrial pressure, left ventricular stroke volumes calculated from 2DE were compared with stroke volumes measured simultaneously by an electromagnetic flowmeter. There was a good correlation between volumes determined from 2DE (y axis) and from casts (x axis) for both the left (r = 0.92; y = 0.2 + 1.1x; SEE = 0.19 ml) and right ventricle (r = 0.90; y = 0.7 + 0.9x; SEE = 0.21 ml). Left ventricular stroke volumes calculated from 2DE correlated well with those measured by the electromagnetic flowmeter (r = 0.87; y = 0.2 + 0.9x; SEE = 0.27 ml). Thus, calculation of fetal ventricular volumes from 2DE images using a biplane Simpson's rule method is feasible and accurate.

Animals↗
PubMed1989

Ebstein's anomaly: echocardiographic and clinical features in the fetus and neonate.

To determine which morphologic features are associated with early death, the complete echocardiograms and medical records of 16 consecutive patients with Ebstein's anomaly and concordant atrioventricular connections who presented in the fetal (n = 5) or neonatal (n = 11) period were reviewed. The cohort was classified into two groups on the basis of survival at 3 months. Group 1 consisted of seven patients who died at less than or equal to 3 months of age, and Group 2 consisted of the nine surviving patients. Comparing Groups 1 and 2, the respective incidence rates of morphologic features that correlated with early death (p less than 0.05) included tethered distal attachments of the anterosuperior tricuspid leaflet (86% versus 11%), right ventricular dysplasia (86% versus 0%), left ventricular compression by right heart dilation (71% versus 11%) and the area of the combined right atrium and atrialized right ventricle being greater than the combined area of the functional right ventricle, left atrium and left ventricle (57% versus 0%) measured in the apical four chamber view. Right ventricular dysplasia was present in all patients with marked right atrial and atrialized right ventricular enlargement, in 86% of patients with tethered anterior leaflets and in 83% of those with left ventricular compression; 86% of patients with right ventricular dysplasia had tethered distal attachments. In conclusion, echocardiography defines morphologic features in the fetus and neonate that are highly predictive of death by 3 months of age.

Ebstein Anomaly↗
PubMed1989

Echocardiographic evaluation of dilated cardiomyopathy in the human fetus.

The diagnosis of dilated cardiomyopathy was established and subsequently confirmed in 6 of 625 fetuses studied by echocardiography. All 6 had structurally normal hearts. Abnormal findings included reduced fractional shortening index in 5, atrioventricular valve regurgitation in 3, abnormal chamber dimensions in 3 and nonimmune hydrops in 4. In 2 fetuses referred because of a family history of dilated cardiomyopathy in previous siblings, echocardiographic abnormalities were absent on a first examination performed at 20 weeks of gestation. This suggested that a normal fetal echocardiogram in a midtrimester fetus does not always rule out the subsequent development of dilated cardiomyopathy. However, all fetuses followed serially developed some abnormality later in pregnancy. Only 2 neonates survived, 1 of whom required a heart transplant during infancy. Death from cardiac failure occurred in 1 fetus and 3 neonates. This study demonstrates that dilated cardiomyopathy may develop during fetal life and might be diagnosed by echocardiography if serial studies are performed. Dilated cardiomyopathy presenting prenatally appears to have a poor prognosis.

Cardiomyopathy, Dilated↗
PubMed1989

Contrast two-dimensional echocardiography in congenital heart disease: techniques, indications and clinical utility.

Saline contrast echocardiography was performed in 889 children from June 1976 through February 1988. One-third of these studies were in postoperative patients. A patent foramen ovale was identified by finding right to left shunting on venous contrast injection in 37% of 127 children studied with a structurally normal heart. The incidence of such shunting was greater at younger ages (55% younger than 1 month versus 22% older than 1 month). In most patients with an atrial or ventricular septal defect, some right to left shunting was demonstrable. The technique was useful in distinguishing different forms of atrial septal defect and identifying muscular ventricular septal defects that were difficult to image directly. The technique was used in the catheterization laboratory to aid in the identification of congenital coronary artery fistulas and was diagnostic in two cases of pulmonary arteriovenous malformation. In patients with situs abnormalities, the technique was useful in identifying the systemic venous connections to the atria. Contrast echocardiography was also used in postoperative evaluations. The technique was useful in identifying patch leaks and residual defects after Senning, Mustard and Fontan operations, and after closure of atrial and ventricular septal defects. Most patients were found to have no superior vena cava obstruction by contrast echocardiography after the Senning or Mustard procedure. Contrast echocardiography continues to be a useful technique in the diagnosis of a wide spectrum of congenital heart disease, as well as in the postoperative evaluation of congenital heart surgery.

Cardiac Catheterization↗
PubMed1989

Accuracy and reproducibility of clinically acquired two-dimensional echocardiographic mass measurements.

Left ventricular mass (LVM) measurements made by the truncated ellipsoid algorithm from clinical two-dimensional echocardiograms (2DE) were compared to autopsy weights in 37 patients. All six 2DE instruments were calibrated with an ultrasound phantom to standardize LVM measurements. Measurements were made by an experienced echocardiographer (LVME) and by an echocardiographer (LVMN) newly trained in LVM measurement from clinical 2DE tapes of patients with LV weights later confirmed at autopsy. LVME (r = 0.91, SEE +/- 41 gm) were more accurate than LVMN for all 2DE, but LVMN equalled LVME in accuracy for technically good 2DE. Interobserver variability was 36 gm, or 17% of LVM for all 2DE, and fell to 27 gm, or 12% of LVM for technically good 2DE. Segmental wall motion abnormalities and time from 2DE to death did not influence measurement accuracy significantly. LVM measurements by the 2DE truncated ellipsoid formula are accurate and reproducible in patients with normal and abnormal hearts.

Adult↗
PubMed1989

Fetal hydrops and death from sacrococcygeal teratoma: rationale for fetal surgery.

Most sacrococcygeal teratomas diagnosed before birth can be managed by planned delivery and postnatal surgery. However, large tumors early in gestation may result in placentomegaly, hydrops, and fetal death and a preeclampsia-like syndrome in the mother. This chain of events may result from high output cardiac failure in the fetus caused by arteriovenous shunting through the tumor. We recently encountered this situation in a fetus at 21 weeks' gestation and performed fetal surgery in an attempt to reverse the process. Excision of the teratoma resulted in reversal of hydrops, diminution of descending aortic flow on Doppler echocardiography, and decrease in placental thickness. Despite these changes, uterine irritability after hysterotomy resulted in labor and delivery of a nonviable premature infant. This case demonstrates that when fetal sacrococcygeal teratoma becomes very large early in gestation, high output cardiac failure can endanger both fetus and mother. In the future, use of Doppler echocardiography may allow appropriate selection of high-risk fetuses. Intervention to prevent arteriovenous shunting through the tumor may offer these fetuses an improved chance for survival.

Adult↗
PubMed1989

Assessment of right ventricular performance by pulsed Doppler echocardiography in patients after intraatrial repair of aortopulmonary transposition in infancy or childhood.

The purpose of this study was to determine whether measurement of aortic blood flow velocity and acceleration by pulsed Doppler ultrasound can be used to assess the global performance of the systemic right ventricle noninvasively in young patients who have undergone intraatrial repair of aortopulmonary transposition. The effect of age at surgery on right ventricular performance in these patients was also studied. Pulsed Doppler velocity profiles of aortic blood flow were analyzed at a mean age of 5.5 years in 24 patients who had undergone intraatrial repair of aortopulmonary transposition either in early infancy (mean age 3.4 +/- 1.3 weeks) or later (mean age 8.5 +/- 6.5 months). Velocity and acceleration variables in these patients were compared with the same variables in 24 age-matched normal subjects and with the performance of their own right ventricle as assessed by two-dimensional echocardiographic measurement of ejection fraction. The 12 patients who underwent early repair had a higher ejection fraction than did the 12 who underwent later repair (mean +/- SD 0.60 +/- 0.07 versus 0.42 +/- 0.10; p less than 0.001). Aortic flow velocity was similar in all patients. Aortic acceleration was normal in patients after early intraatrial repair of aortopulmonary transposition (20.8 +/- 2.3 m/s2), but was abnormally slow in patients after late repair (11.1 +/- 1.8 m/s2; p less than 0.001), thus suggesting that the latter group had diminished right ventricular performance. Concomitantly, acceleration time and ratio of acceleration time to ejection time were increased in patients after late repair.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Flow Velocity↗
PubMed1989

Diagnosis of coronary artery fistula by two-dimensional echocardiography, pulsed Doppler ultrasound and color flow imaging.

Ten consecutive patients with a coronary artery fistula, aged 1 day to 4 years, were studied by two-dimensional echocardiography, pulsed Doppler ultrasound and color flow imaging. All patients underwent cardiac catheterization, and seven patients had surgical closure of the fistula. The origin, course and site of drainage of the coronary artery fistula were correctly identified prospectively by echocardiographic examination in all patients. Color flow imaging was particularly helpful in visualizing the site of drainage of the fistula. Diameters of the right and left coronary arteries at their origin and of the aortic root were measured from two-dimensional echocardiographic frames and compared with measurements obtained in normal children. The ratio of coronary artery diameter to aortic root diameter in normal children was 0.14 +/- 0.03 (mean +/- SD) for the right coronary artery and 0.17 +/- 0.03 for the left coronary artery. These normal ratios were greatly exceeded for coronary arteries feeding the fistula, and ranged from 0.68 to 0.84 for the right coronary artery and from 0.34 to 0.52 for the left coronary artery. All anatomic information needed for surgical treatment of coronary artery fistula was consistently obtained by echocardiography with color flow imaging. The fistula was closed from within the heart in five patients and by ligation from the epicardial surface in two patients. In these latter patients, intraoperative color flow imaging at the time of ligation proved to be extremely valuable in achieving complete closure.

Cardiac Catheterization↗
PubMed1989

High-output cardiac failure in fetuses with large sacrococcygeal teratoma: diagnosis by echocardiography and Doppler ultrasound.

With two-dimensional echocardiography and Doppler ultrasound, we demonstrated high-output cardiac failure in three fetuses with large sacrococcygeal teratomas. All fetuses had normal cardiac structure, dilated ventricles maintaining a normal fractional shortening index, a dilated inferior vena cava reflecting the increased venous return from the lower body, pericardial and pleural effusions as a manifestation of fetal hydrops, and a markedly thickened placenta. When fetal hydrops was present, the combined ventricular output was very high (mean 1280 ml/min/kg; normal 553 +/- 153 (SD)). Descending aortic flow was also sharply increased (mean 930 ml/min/kg; normal 184 +/- 20), as was placental flow (mean 480 ml/min/kg, normal 110 +/- 26). High-velocity arterial flow signals were also found within the tumor. In one fetus studied serially, placental thickness and tumor diameter increased rapidly; placental flow as a percentage of descending aortic flow decreased, indicating a further increase of flow to the tumor. These abnormal hemodynamic changes were reversed after the fetus's teratoma was surgically removed. We conclude that the sacrococcygeal teratoma acts as a large arteriovenous fistula, which causes high-output cardiac failure. Surgical removal of the teratoma in a previable fetus with such hemodynamic findings may prove to be the most effective treatment.

Echocardiography↗
PubMed1989

The current role of Doppler echocardiography in the diagnosis of heart disease in children.

New Doppler ultrasound technology has caused a change in the approach to the diagnosis of congenital heart disease. Pulsed Doppler ultrasound continues to be of great value for measuring cardiac output ventricular performance and for calculating pulmonary to systemic flow ratios. Continuous wave Doppler ultrasound by virtue of its ability to detect high velocity accurately remains the premier technique for determining pressure drop across valves or across shunts. Pulsed Doppler ultrasound remains a valuable test for defining many lesions including patent ductus arteriosus.

Aortic Coarctation↗
PubMed1988

Doppler ultrasound evaluation of valvar pulmonary stenosis from multiple transducer positions in children requiring pulmonary valvuloplasty.

The modified Bernoulli equation has been used to determine the peak pressure difference across stenotic pulmonary valves. The direction of the poststenotic jet may be eccentric in relation to the axis of the pulmonary artery. Consequently, the maximal velocity obtained from the parasternal transducer position may inaccurately estimate peak pressure difference. Thus, Doppler-derived estimates of pressure difference from the parasternal, subcostal, apical, and suprasternal notch transducer positions were compared with peak-to-peak pulmonary artery to right ventricle catheter withdrawal pressure differences in 24 patients admitted for pulmonary valvuloplasty. Suprasternal, subcostal or apical transducer positions produced higher maximal velocities than the parasternal transducer position in 12 of 24 patients when the studies were performed before cardiac catheterization and in 8 of 12 patients when performed during cardiac catheterization. The Doppler-derived estimates using the highest maximal velocity predicted catheterization pressure difference accurately when the measurements were not performed simultaneously (y = 1.05x - 3.3, r = 0.86, standard error of the estimate +/- 18.7 mm Hg) and the correlation was closer when the measurements were performed simultaneously (y = 1.09x - 2.7, r = 0.97, standard error of the estimate +/- 9.4 mm Hg). The transducer position that yielded the highest maximal velocity in an individual patient was the same before and after valvuloplasty. In all groups, the correlation with pressure at cardiac catheterization was improved by using the highest maximal velocity rather than the parasternal maximal velocity.

Cardiac Catheterization↗