Search PubMed⌕ Search

Biomedical subjects

N H Silverman

Publications and source records attributed to N H Silverman.

At least 163 records · Page 9Linked to original sources
PubMed1982

Ventricular septal defect with silent discrete subaortic stenosis.

Subaortic stenosis is rarely mentioned as a lesion that may be associated with a ventricular septal defect. We have encountered 4 patients with discrete subaortic stenosis adjacent to a ventricular septal defect, all of whom posed significant problems in diagnosis. In all 4 patients the subaortic stenosis was silent clinically and in 3 cases the obstruction was also not detected at the initial cardiac catheterization and angiocardiography. In the latter 3 cases, after surgical closure of the ventricular septal defect, there was a loud systolic murmur initially thought to be due to a small residual ventricular septal defect. In time, the clinical findings became more typical of isolated subaortic stenosis. In each of these cases the obstruction was verified at cardiac catheterization with peak systolic pressure gradients of 145, 45, and 70 mmHg. During reoperation, a discrete subaortic shelf was found opposite the patch used to close the ventricular septal defect. In the 4th case, the subaortic stenosis was unsuspected by clinical evaluation but was diagnosed by echocardiography as well as at cardiac catheterization, and both the ventricular septal defect and subaortic stenosis were corrected at the initial operation. A discrete subaortic shelf situated adjacent to a ventricular septal defect may be "silent," producing minimal, if any, pressure gradient and may pose diagnostic difficulties. Failure to recognize such a shelf and to remove it at the time of surgical closure of the ventricular septal defect, may result in the creation of a severe subaortic obstruction.

Adolescent↗
PubMed1982

Evaluation of infradiaphragmatic total anomalous pulmonary venous connection with two-dimensional echocardiography.

In three newborn infants with infradiaphragmatic total anomalous pulmonary venous connection, the common pulmonary vein was visualized with two-dimensional echocardiography and validated with saline contrast injections. The transducer was placed in the subcostal region in a sagittal body plane so as to image the descending aorta and the vertebral column. The common pulmonary vein, which connected the pulmonary veins to a systemic vein in the abdomen, was seen lying parallel and anterior to the descending aorta and to the left of the inferior vena cava. With peripheral venous contrast injections, contrast echoes first filled the inferior vena cava and then the descending aorta because of obligatory right-to-left atrial shunting. The common pulmonary vein was the only structure that remained free of contrast echoes. Thus, contrast echocardiography provided a method for identifying the site of pulmonary venous drainage and for distinguishing the common pulmonary vein from other structures such as the inferior vena cava. In cyanotic infants with respiratory distress, two-dimensional contrast echocardiography permits a rapid diagnosis of infradiaphragmatic total anomalous pulmonary venous connection.

Diaphragm↗
PubMed1981

Left atrial volume estimation by two-dimensional echocardiography.

We examined 12 patients aged six months to 76 years by echocardiography to determine left atrial volume. The results were compared with angiographic left atrial volumes calculated by the biplane Simpson's rule method. Three two-dimensional planes were used: precordial long axis, apical two-chamber, and four-chamber. Area outlines were traced using a light pen computational system providing single plane area length estimates of left atrial volume. The two apical left atrial outlines were combined, and Simpson's rule method was used to calculate left atrial volume. M-mode echocardiograms performed on these patients were used to estimate left atrial volume. As the results of covariance analysis showed that there was no significant difference in the line of regression in systole and diastole, these data were pooled for subsequent comparison with angiography. The closest correlation with angiography was the biplane Simpson rule method with the echocardiographic left atrial volume (Y) = 1.0, angiographic volume (X) + 6.3 ml, r = 0.86. The single plane area length estimates also correlated well with angiography, but correction factors were required. M-mode estimates of left atrial volume could only correlate to angiography using a power function y = 3.7 X(1.80), r = 0.69. We conclude that left atrial volume can be determined by two-dimensional echocardiography and that this technique is superior to M-mode echocardiography.

Adolescent↗
PubMed1981

Cardiovascular effects of acute hemorrhage in fetal lambs.

The effects of acute hemorrhage were studied in two groups each with six fetal lambs (100-116 amd 128-147 days gestation) 3-4 days after we implanted catheters. Fetal blood pressures, heart rate, arterial blood gases and pH, and combined ventricular output and its distribution (radionuclide-labeled microsphere technique) were measured before and 5 min after removal of 15% of fetal-placental blood volume measured by 125I-albumin dilution. Because there were no differences in responses in the two age groups, the data were pooled. Fetal arterial mean pressure fell significantly (50.7 +/- 2.5 to 45.5 +/- 2.6 mmHg) as did heart rate (186 +/- 6 to 151 +/- 13 beats/min) and arterial blood pH (7.39 +/- 0.02 to 7.30 +/- 0.02); arterial blood carbon dioxide tension rose (39.7 +/- 29 to 44.1 +/- 4.4). Combined ventricular output fell from 610 +/- 58 to 448 +/- 45 ml . kg-1 . min-1 (P < 0.05). Blood flow to the umbilical-placental circulation, as well as to the fetal body, fell significantly. Blood flow to the kidneys, gastrointestinal tracts, and lungs also fell, but flow to other organs was maintained. Blood volume reduction in the fetus markedly influences blood gas exchange, because it results in a reduction of umbilical-placental blood flow associated with the fall in arterial pressure.

Acid-Base Equilibrium↗
PubMed1981

Suprasternal notch echocardiography: a two-dimensional technique for evaluating congenital heart disease.

Two-dimensional suprasternal notch echocardiography was performed in 1033 patients, ages 1 day to 18 years. For the long-axis suprasternal notch view, the transducer was positioned in the suprasternal notch and angled to obtain a plane passing between the right nipple and left scapular tip. In this view, the entire aortic arch, vessels to the head and neck, right pulmonary artery and right bronchus were imaged. The long-axis view was useful for evaluating coarctation and interruption of the aorta, hypoplastic left heart, aortic and pulmonic stenosis and cervical aortic arch. For the short-axis suprasternal notch view the transducer was positioned in the suprasternal notch and angled to obtain a coronal body plane. In this view the transverse aorta, right pulmonary artery, left atrium, innominate veins and superior vena cava were imaged. The short-axis view was useful in the evaluation of children with increased or decreased pulmonary blood flow, persistent left superior vena cava, total anomalous pulmonary venous return to the right superior vena cava, and superior vena caval obstruction after Mustard's operation. In the evaluation of children with congenital heart disease, the suprasternal notch views added significant information to the two-dimensional echocardiographic examination.

Adolescent↗
PubMed1981

Detection of intracranial arteriovenous fistula by two-dimensional ultrasonography.

Three newborn infants who had severe congestive heart failure caused by an arteriovenous malformation of the vein of Galen were evaluated by two-dimensional ultrasonography. Examination of the heart from standard echocardiographic planes showed right atrial and right ventricular dilatation. The superior vena cava, ascending aorta and the vessels to the head and neck were enlarged. Contrast two-dimensional echocardiography from a peripheral vein showed right-to-left atrial shunting and early superior vena cava recirculation. With the transducer positioned in the anterior fontanel or against the temporal bone, two-dimensional sector scans of the brain were obtained in the coronal, sagittal and transverse planes. A large echo-free space that represented an aneurysm of the vein of Galen was seen within the brain. During contrast injection into a peripheral vein, microcavitations that passed from right to left at the atrial level were seen filling the vein of Galen aneurysm. In two infants in whom beryllium wire was placed in the fistula to induce thrombosis, postoperative ultrasonography showed a dense mass of echoes arising from the wire and persistent left-to-right shunting through the fistula. In infants presenting in the first week of life with congestive heart failure and cyanosis of unknown etiology, two-dimensional ultrasonography provides a rapid, safe method for detecting intracranial arteriovenous malformation.

Brain↗
PubMed1981

Superior vena caval obstruction after Mustard's operation: detection by two-dimensional contrast echocardiography.

To assess superior vena caval (SVC) obstruction after the Mustard operation for transposition of the great arteries, we performed two-dimensional contrast echocardiography (2-D contrast echo) in 18 patients, ages 1-9 years. Sterile saline was injected into a peripheral scalp or arm vein while the junction of the inferior vena cava (IVC) and the systemic venous atrium (SVA) was imaged from the subcostal long-axis plane. The results of 2-D contrast echo were compared with those obtained at cardiac catheterization. In nine patients, contrast passed from the SVC to the SVA and the IVC remained free of contrast echoes. At catheterization, these patients had no SVC obstruction by angiography and minor SVC-SVA mean pressure differences (0-4 mm Hg). In five patients, contrast passed from the SVC into the SVA. Within a few cardiac cycles, contrast from azygos-IVC collateral vessels flowed in the IVC toward the SVA. At catheterization, these patients had partial SVC obstruction by angiography and SVC-SVA mean pressure differences of 9-13 mm Hg. In four patients, the SVA was filled only by contrast arriving from the IVC by way of azygos-IVC collateral vessels. At catheterization, these patients had complete SVC obstruction and SVC-SVA mean pressure differences of 14-20 mm Hg. Two-dimensional contrast echocardiography is a simple, accurate, noninvasive method for detecting SVC obstruction after Mustard's operation and allows differentiation of complete from partial SVC obstruction.

Cardiac Catheterization↗
PubMed1980

Congenital left ventricular inflow obstruction evaluated by two-dimensional echocardiography.

Several forms of congenital heart disease that cause left ventricular inflow obstruction have similar M-mode findings, and frequently the exact anatomic diagnosis cannot be made by M-mode echocardiography alone. We examined five children with various forms of left ventricular inflow obstruction using two-dimensional echocardiography. The diagnosis was confirmed by cardiac catheterization and surgery in all five patients. In one patient with congenital mitral valve stenosis, a thick mitral valve with two papillary muscles was imaged. This patient was easily distinguished from a second child with parachute deformity of the mitral valve in whom a single papillary muscle arising from the left ventricular apex was seen. These two patients with mitral valve stenosis were easily differentiated from the three patients in whom the left ventricular inflow obstruction was caused by a membrane within the left atrium. The membrane could be seen in several spatial planes; however, we could not distinguish by two-dimensional echocardiography one child who had cor triatriatum from the other two patients who had a supravalvar mitral ring. Because of its spatial anatomic display, the two-dimensional echocardiogram provides information for a more detailed anatomic diagnosis in children with congenital left ventricular inflow obstruction.

Adolescent↗
PubMed1979

Echocardiographic evaluation of ventricular septal aneurysms.

The spontaneous closure of ventricular septal defects is frequently associated with septal aneurysm formation. In this paper we discuss the M-mode and two-dimensional echocardiographic findings in nine children with aneurysms of the ventricular septum in association with ventricular septal defects. In all patients the diagnosis was confirmed by angiography. The ventricular septal aneurysms were detected by both M-mode and two-dimensional echocardiography. With M-mode echocardiography, septal aneurysms could be recognized by a pattern of multiple systolic echoes within the right ventricle. With two-dimensional echocardiography, the protrusion of the septal aneurysm into the right ventricle could be seen from several views and the location and the relative size of the aneurysm assessed. Echocardiographic techniques useful in the detection of ventricular septal aneurysms are discussed and examples presented.

Adolescent↗
PubMed1979

Left ventricular volume from paired biplane two-dimensional echocardiography.

To evaluate the applicability of two-dimensional echocardiography to left ventricular volume determination, 30 consecutive patients undergoing biplane left ventricular cineangiography were studied with a wide-angle (84 degrees), phased-array, two-dimensional echocardiographic system. Two echographic projections were used to obtain paired, biplane, tomographic images of the left ventricle. We used the short-axis view (from the precordial window) as an anolog of the left anterior oblique angiogram, and the long-axis, two-chamber view (from the apex impulse window) as a right anterior oblique angiographic equivalent. A modified Simpson's rule formula was used to calculate systolic and diastolic left ventricular volumes from the biplane echogram and the biplane angiogram. These methods correlated well for ejection fraction (r = 0.87) and systolic volume (r = 0.90), but only modestly for diastolic volume (r = 0.80). These correlations are noteworthy because 65% of the patients had significant segmental wall motion abnormalities. The volumes determined from the minor-axis dimensions of M-mode echograms in 23 of the same patients correlated poorly with angiography.

Adult↗