Biomedical subjects
Publications and source records attributed to N H Silverman.
The clinical features, diagnostic studies and surgical treatment of a subvalvular mitral aneurysm of the left ventricle are described. The infant presented at 9 weeks of age with large apical ventricular septal defects and pulmonary hypertension. The subvalvular aneurysm was an incidental finding. Both lesions were treated surgically.
A coronary-cameral fistula was inspected clinically by two-dimensional and pulsed Doppler ultrasound. At cardiac catheterization a fistulous connection between the left coronary artery and the right ventricle was observed. Contrast echocardiography using agitated saline solution injected into the aortic catheter clearly showed the passage of microcavitations into the left and the right ventricles confirming the connection of the fistula to both chambers. Contrast echocardiography is a valuable technique that can help define the site of drainage of coronary artery fistulas.
Of 466 fetuses who underwent cardiac ultrasound examination with cross-sectional and M mode echocardiography and pulsed Doppler ultrasound and in whom we were able to follow the natural history, 12 were found to have atrioventricular valve insufficiency and nonimmune hydrops. Eleven fetuses (all of whom had structural heart disease) died either in utero or during the early postnatal period. In the one surviving hydropic fetus with supraventricular tachyarrhythmia and atrioventricular valve regurgitation but without structural heart disease, all the abnormalities disappeared on treatment with digoxin and verapamil. Seven fetuses who had atrioventricular valve insufficiency but did not develop nonimmune hydrops all survived pregnancy and the early neonatal period. The syndrome of atrioventricular valve insufficiency, nonimmune hydrops, and structural heart disease has a poor prognosis. The hydrops in this instance reflects fetal cardiac failure related to venous hypertension and low colloid oncotic pressure.
Right ventricular (RV) wall thickness was measured from M-mode echocardiograms at end-diastole from both the parasternal and subcostal approaches in 50 children of various body surface areas (0.24 to 1.68 m2). The measurements were obtained from M-mode recordings generated from sector scans to ensure precise location and position. Twenty-three children had normal hearts, and 27 had various congenital heart defects that may be associated with RV hypertrophy. Corresponding measurements of the RV wall thickness at end-diastole from the 2 approaches were similar. Subcostal echocardiographic measurement of RV wall thickness was found to be a reliable alternative to parasternal measurement in children with normal hearts and in those with congenital heart disease and RV hypertrophy.
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A heart with an atrioventricular septal defect is characterized by absence of the atrioventricular muscular and membranous septa, a common atrioventricular junction, an unwedged position of the aortic valve annulus and disproportionate inlet--outlet dimensions of the ventricular septum. The clinical and post-mortem findings are described of a case which had intact atrial and ventricular septa but had all the other anatomical hallmarks of atrioventricular septal defect. The problems in clinical diagnosis may be overcome by cross-sectional echocardiography.
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M mode and cross sectional echocardiography was carried out in three cases of cor triatriatum sinistrum (two infants and one adult). In two cases a peculiar double arch appearance, not previously reported, was found. All three cases were referred for surgery without cardiac catheterisation, and the diagnosis proved to be correct. The characteristic echocardiographic feature of cor triatriatum is an intra-atrial membrane detected in multiple planes of examination, curving anteroinferiorly and inserting some distance away from the mitral valve ring, proximal to the left atrial appendage. Superiorly the membrane runs parallel to, and a short distance behind, the aortic root creating a superior recess of the distal left atrial chamber. These features differentiate cor triatriatum from a supravalvar mitral ring. During diastole the membrane moves forward towards the mitral valve funnel. This, together with the arching appearance of the membrane on four chamber views and the more superior position of the membrane, makes it possible to distinguish cor triatriatum from total anomalous pulmonary venous drainage to the coronary sinus. From a review of past experience at the Brompton Hospital of the diagnostic accuracy of cardiac catheterisation in this condition, it is concluded that cross sectional echocardiography is superior to angiography as a technique for diagnosing cor triatriatum.
The precise method of surgical repair of double outlet right ventricle depends both on the relation of the interventricular communication to the cardiac outlets and on the course and insertion of the atrioventricular valve tension apparatus. It may be difficult to connect the interventricular communication with one or other outlet or both either because the interventricular communication is too far from the outlets or because atrioventricular tension apparatus interposes between them. This study was carried out in order to establish whether these details could be recognised preoperatively using cross sectional echocardiography. Forty two echocardiograms were reviewed retrospectively from patients with double outlet right ventricle, excluding those with atrioventricular septal defects and atrioventricular discordance. Ten further such patients were studied prospectively. The diagnosis was confirmed at open heart surgery in 19 patients. The relation of the great arteries and their outlet tracts to each other and to the interventricular communication was readily and accurately predicted. Four patients (7.7%) had no infundibular septum. The remaining 48 had such a septum. In 27 (52%) the interventricular communication was overridden by a great artery. In 14 (27%) it was roofed by the ventriculoinfundibular fold, and in 11 (21%) it was confined to the inlet or trabecular septa. The insertion of chordae tendineae limited the possible surgical options in 12 patients (23.1%) who were distributed unpredictably among the above groups. Four patients had straddling atrioventricular valves. In five, tricuspid tension apparatus inserted into the underside of the infundibular septum and, in two, into the roof of the defect. In one patient the mitral valve inserted into the defect floor. Tricuspid tension apparatus inserted into the floor of the defect in a further nine patients, but this does not compromise surgery. Thus in double outlet right ventricle cross sectional echocardiography can provide unique information necessary for planning of rational surgical management.
We studied neonates with the infradiaphragmatic form of total anomalous pulmonary venous drainage by a combination of cross-sectional echocardiography and pulsed Doppler ultrasound. The diagnosis by ultrasound was made prospectively in all six patients. Three large vascular channels could be observed passing through the diaphragm from the subcostal parasagittal plane. The vessels were identified as the descending aorta (to the left), the inferior vena cava (to the right), and the anomalous pulmonary venous channel (in the center). The vessels were insonated in turn, with pulsed Doppler ultrasound, and the characteristic normal flow signals in the aorta and inferior vena cava were obtained. The signal from the anomalous pulmonary vein was a continuous venous signal, the direction of flow being away from the heart. Pulsed Doppler ultrasound allows accurate recognition of the anomalous pulmonary venous channel without the use of contrast echocardiography.
Magnetic resonance imaging (MRI) was conducted with use of the spin-echo technique (0.35 Tesla) in 22 patients with a variety of congenital and cardiovascular anomalies and in 16 normal volunteers. Electrocardiographic (ECG) synchronization of the data acquisition produced transverse, parasagittal, and coronal tomograms that were used to define size and relationship of the great vessels and internal cardiac structures. MRI findings were corroborated by angiography and sector-scan echocardiography. In most patients the diagnosis had been established before the MRI study. MRI detected all of 11 abnormalities at the level of the great vessels, all of six atrial septal abnormalities, and 10 of 11 ventricular septal defects. Images of poor quality resulting from patient motion were obtained in the one instance in which a small ventricular septal defect was not imaged. Of two patients with Ebstein's anomaly, the displacement of the tricuspid leaflets was shown in one patient but was not evident in another. Complex anomalies such as double-outlet right ventricle, uncorrected L-transposition, single atrioventricular valve, single ventricle, and common ventricle were clearly shown by MRI. Initial experience with MRI has indicated the effectiveness of this technique for defining great vessel and internal cardiac anatomy in patients with congenital heart disease. This is accomplished without the use of contrast media and is thus a completely noninvasive technique for cardiovascular diagnosis.
Ten hearts were cut in planes to simulate echocardiographic cuts which may be taken to visualise the anatomy of the cardiac chambers and great arteries. The various myocardial wall segments were named from these sections by referring to their position in the reconstituted heart. The sections were studied in their correct anatomical position. In this way they provide a reference for appropriate orientation of echocardiographic images.
This study was designed to develop a two-dimensional echocardiographic method of measuring the mass of the left ventricle. The general formula for an ellipse was used to derive an algorithm that described the shell volume of concentric truncated ellipsoids. In 10 canine left ventricular two-dimensional echocardiograms, this algorithm accurately predicted postmortem left ventricular mass (r = .98, SEE +/- 6 g) and was independent of cardiac cycle phase (systole vs diastole, r = .92).
Two-dimensional echocardiography of cardiac situs, connections, and malpositions from a variety of planes is discussed.
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An asymmetrical crying facies due to hypoplasia or absence of the depressor anguli oris muscle (DAOM) was observed in 23 infants and children. The cases were divided into two groups. Group 1 consisted of 12 patients who had associated cardiac abnormalities. In group 2 were 11 patients who either had other non-cardiac abnormalities (6) or no other abnormalities (5). The associated cardiac anomalies recorded in the literature are reviewed and 2 infants in this series are reported with abnormalities not previously described. The results of chromosomal analysis have generally been found to be normal, although a patient in our series was found to have trisomy E (18). The incidence of hypoplasia of the DAOM in newborn infants in a maternity hospital hospital is assessed and was found to be lower than reported in other studies. It is concluded that a detailed and careful examination for congenital abnormalities should be carried out on every child with an asymmetrical crying facies.
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