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Biomedical subjects

N H Silverman

Publications and source records attributed to N H Silverman.

At least 127 records · Page 7Linked to original sources
PubMed1988

Pulmonary artery origin of the left coronary artery: diagnosis by two-dimensional echocardiography, pulsed Doppler ultrasound and color flow mapping.

Five children, aged 0.2 to 6.7 years, with pulmonary artery origin of the left coronary artery proved by angiography underwent echocardiographic examination from 1985 through 1986. Prospective identification of this condition was achieved by two-dimensional echocardiography alone in two patients. Using a parasagittal plane from the second or third intercostal space, identification of the anomalous origin from the pulmonary artery was also possible in the other children on subsequent examination. In all of these studies the right coronary artery was considerably enlarged. The ratio of the diameters of the right coronary artery and the aortic root was 0.25 to 0.33 (normal 0.12 +/- 0.02). Flow mapping by color Doppler ultrasound in three children studied most recently and peripheral arterial or aortic root contrast echocardiography identified the site of entry of the coronary flow into the pulmonary artery. The flow disturbance was detected on the aortic surface of the pulmonary artery opposite the portion from where the flow from a patent ductus is usually identified. Pulsed Doppler ultrasound identified the flow disturbance in the pulmonary artery in only three of the children. The two youngest patients did not demonstrate turbulence on pulsed Doppler ultrasound, but they were not examined by color Doppler ultrasound. The accuracy of noninvasive detection of pulmonary artery origin of the left coronary artery by ultrasound is improved by the use of a combined echocardiographic approach.

Aorta↗
PubMed1988

Determination of pulmonary to systemic blood flow ratio in children by a simplified Doppler echocardiographic method.

Doppler echocardiographic determination of the pulmonary to systemic blood flow (Qp/Qs) ratio requires calculation of pulmonary artery and aortic luminal areas and integrals of the Doppler systolic velocity curves. To simplify the Doppler calculation of the Qp/Qs ratio, the square of the ratio of pulmonary to aortic luminal diameters, substituted for the ratio of vessel areas, was multiplied by the ratio of pulmonary to aortic peak flow velocities, substituted for the ratio of velocity time integrals. The Qp/Qs ratios were calculated by both the conventional and the simplified Doppler method in 42 children, 1 month to 16 years of age. Fifteen children had no evidence of shunt and 27 had an intracardiac left to right shunt at the atrial or ventricular level, or both. In children with a shunt, the Qp/Qs ratio obtained at cardiac catheterization by oximetry ranged from 1.4:1 to 4.3:1. Both the conventional and the simplified Doppler Qp/Qs ratios correlated well with the oximetric Qp/Qs ratios (r = 0.94 and 0.93, respectively). Since the pulmonary to aortic luminal area ratio and velocity time integral ratio varied in each patient, neither measurement alone correlated well with the oximetric Qp/Qs ratio and, therefore, neither alone could be used as an estimate of the Qp/Qs ratio. The simplified Doppler calculation of the Qp/Qs ratio, which requires less time and no computer facilities, provides an excellent estimate of the Qp/Qs ratio in children.

Adolescent↗
PubMed1988

Evaluation of the responsiveness of elevated pulmonary vascular resistance in children by Doppler echocardiography.

Changes in the Doppler indexes, acceleration time (AcT), right ventricular ejection time (RVET), AcT/RVET ratio and pulmonary artery peak velocity were measured as were changes in pulmonary artery pressure and pulmonary vascular resistance in 21 children with pulmonary hypertension due to a large interventricular communication. In 11 children pulmonary vascular resistance was greater than 4.6 U/m2 (mean 8.6 +/- 1.6), whereas in 10 it was less than 4.5 U/m2 (mean 3.4 +/- 0.2). Although both groups demonstrated acceleration time and AcT/RVET values above normal, there were no significant differences in these values between the groups with high and low pulmonary vascular resistance. With administration of a pulmonary vasodilator pulmonary vascular resistance decreased in 11 responders by greater than 50% of baseline values (from 5.3 +/- 0.7 to 1.6 +/- 0.3 U/m2), whereas in the 10 nonresponders mean pulmonary vascular resistance decreased from 7.0 +/- 1.9 to 4.9 +/- 1.1 U/m2. There was no significant change in the Doppler indexes except for an increase in pulmonary artery peak velocity in the responders from 1.34 +/- 0.07 to 1.66 +/- 0.06 m/s (p less than 0.001). The results indicate that Doppler echocardiography cannot predict either the level of increased pulmonary vascular resistance or the degree of responsiveness sufficiently to obviate the need for cardiac catheterization in patients with interventricular communication and pulmonary hypertension.

Adolescent↗
PubMed1988

Doubly committed subarterial ventricular septal defects: echocardiographic features and surgical implications.

Doubly committed subarterial (supracristal, subpulmonary) ventricular septal defects are often complicated by aortic regurgitation resulting from aortic valve herniation into the defect. The clinical, echocardiographic and catheterization findings in 48 patients aged 0.3 to 46.4 years (median 9.5) with a doubly committed subarterial ventricular septal defect were reviewed. Aortic valve herniation was present in 38 (79%) and 55% of these had aortic regurgitation. The prevalence of both findings increased gradually with advancing age. The defect was closed surgically in 41 patients. Surgery during the first 2 years of life (median 0.4 year) was performed in 13 patients (group I), mainly because of a large shunt with a pulmonary to systemic flow ratio (Qp/Qs) 3.8 +/- 1.4 (mean +/- SD). Aortic regurgitation was present preoperatively in two patients (15%), persisted postoperatively in one patient and did not develop in any after repair (median duration of follow-up 2.3 years, range 0.1 to 7.4). In the other 28 patients (group II) surgery was performed between 4.8 and 46.4 years of age (median 11.5). These patients were generally less symptomatic and had a smaller shunt (Qp/Qs 1.5 +/- 0.5, p less than 0.001). Preoperative aortic regurgitation was present in 18 (64%). It persisted in 15 postoperatively, but in 13 of these it had diminished. Two-dimensional echocardiography in multiple views identified the site of the ventricular septal defect in all patients. Serial echocardiographic examinations demonstrated the progressive nature of aortic valve herniation, the partial occlusion of the defect by the herniated sinus and the development of aortic regurgitation. These findings suggest that timely surgical closure of these defects may prevent aortic regurgitation.

Adolescent↗
PubMed1987

Effects of activity on ascending aortic velocity in children with valvar aortic stenosis.

The peak velocity of aortic blood flow was measured in 12 normal children and 20 children with valvar aortic stenosis (AS) by continuous-wave Doppler ultrasound (CWD). Measurements were made at rest, after 2 forms of exercise and, in the 11 children who underwent cardiac catheterization, while under sedation. The exercise was both formal cycle ergometry and a 200-meter jog. The peak velocity in normal children was 1.5 +/- 0.2 m/s at rest, increasing to 2.1 +/- 0.4 m/s (p less than 0.01) after running and to 1.9 +/- 0.4 m/s (p less than 0.01) after cycling. Peak velocity in children with AS was 3.5 +/- 0.8 m/s at rest, increasing to 4.4 +/- 0.8 m/s (p less than 0.01) after running and to 4.5 +/- 0.5 m/s (p less than 0.01) after cycling. The increase in peak velocity was greater in children with AS than in normal children. Measurements of left ventricular (LV) aortic pressure differences by cardiac catheterization were compared to those made by CWD, using the modified Bernoulli equation. The best correlation of the CWD prediction of LV aortic pressure differences was achieved when the children were sedated. The peak velocity of blood flow in the ascending aorta varied with level of activity, and this variability must be considered when using the Bernoulli equation to predict LV aortic pressure differences. CWD prediction of the LV aortic pressure difference was best when the child was sedated (r = 0.98). It is therefore prudent to consider the velocity measurement proximal to the AS to calculate LV aortic pressure differences more accurately unless the child is sedated.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1987

Prenatal detection of truncus arteriosus by ultrasound.

This report describes the echocardiographic findings of truncus arteriosus, right aortic arch, and persistent left superior vena cava draining into the coronary sinus in a 32-week-old fetus, in whom the diagnosis was confirmed by autopsy.

Adult↗
PubMed1987

Cross-sectional and contrast echocardiography in the diagnosis of interatrial communications through the coronary sinus.

An interatrial communication through the mouth of the coronary sinus is a rare cardiac anomaly. It is usually associated with a left superior caval vein draining into the coronary sinus and is frequently part of a complex congenital malformation of the heart. Failure to recognize this defect before surgical repair of the primary cardiac lesion may lead to persistent interatrial shunting, which may in turn cause postoperative cyanosis. This report describes two cases of interatrial communication through the coronary sinus diagnosed prospectively by echocardiography. It demonstrates the important role of contrast echocardiography in the evaluation of patients suspected of having this malformation.

Coronary Circulation↗
PubMed1986

Importance of (perimembranous) ventricular septal aneurysm in the natural history of isolated perimembranous ventricular septal defect.

Records were reviewed of 247 patients found to have isolated perimembranous ventricular septal defect (VSD) on cross-sectional echocardiography. Patients were separated into 2 groups: those in whom a perimembranous ventricular septal aneurysm (VSA) was associated with the VSD (group A, 77% of patients) and those in whom a VSA was not present (group B, 23%). The VSD was assessed by clinical (125 in group A, 24 in group B) and hemodynamic criteria (65 in group A, 33 in group B). The median follow-up period was 27 months (range 3 months to 25 years). In group A, the VSD closed spontaneously in 11% of the patients, improved clinically in 33% and required surgical closure in 11%. In group B, the VSD closed spontaneously in only 2%, improved clinically in 16% and required surgical closure in 47%. When considering larger VSDs only, 28% required surgery in group A, whereas 84% required surgery in group B (p less than 0.001). The VSA was found at the first echocardiographic examination in 94% of the studies. Thus, VSA is found in a large proportion of patients with perimembranous VSD. It occurs as an early phenomenon and is an important mechanism of closure. The presence of a VSA appears to confer a more favorable prognosis in perimembranous VSD except in patients with Down's syndrome.

Adolescent↗
PubMed1986

Contrast echocardiography in the diagnosis of anomalous left coronary artery arising from the pulmonary artery.

We have demonstrated an anomalous left coronary artery originating from the main pulmonary artery by saline contrast echocardiography. The anomalous vessel was easily identified using contrast injections into the ascending aorta at catheterization and into a radial artery cannula following catheterization. Contrast echocardiography may be useful in the diagnosis of this lesion when two-dimensional and Doppler echocardiography fail to show the anomalous vessel.

Cardiac Catheterization↗
PubMed1986

Atrioventricular septal defects: cross-sectional echocardiographic and morphologic comparisons.

We examined the cross-sectional echocardiographic findings of 171 patients with atrioventricular septal defects. The echocardiographic findings were confirmed by angiography, surgery and/or autopsy. The echocardiographic findings determined whether the common atrioventricular junction was guarded by a common valve or separate right and left valves. In addition, we were able to judge whether the bridging leaflets were related to the septal structures so as to permit both interatrial and interventricular communications [127 cases] or whether the interatrial communication ("ostium primum atrial septal defect") [43 cases] or an interventricular communication [1 case] existed in isolation. Defects existing with a common atrioventricular valve could be further classified as having minimal bridging of the antero-superior leaflet (Rastelli Type A [113 cases]); intermediate bridging (Rastelli Type B [3 cases]); or extreme bridging (Rastelli Type C [11 cases]). Of the patients with Down's syndrome, 9 had separate right and left valves while 66 had a common valve, all the latter existing in the setting of minimal bridging of the antero-superior leaflet. In the overall group, there were 9 cases having an unbalanced ventricular mass, 5 with right ventricular dominance and 4 with left dominance. Other associated defects were common. The echocardiographic findings were supplemented by pulsed Doppler examination. Atrioventricular valve insufficiency, when mild, was frequently demonstrated only in the right atrium just above the leaflets of the atrioventricular valve. When there was more severe valve insufficiency the regurgitant jet could be detected for greater distances behind the atrioventricular valve and in either or both atria, but more frequently in the left atrium. As might be anticipated in view of the complexity of the lesion, a combined imaging approach yielded the most accurate results.

Adolescent↗
PubMed1986

Congenital heart disease: gated MR imaging in 72 patients.

Seventy-two patients (aged 2 months to 75 years; mean 23 years) with a variety of congenital anomalies of the heart and great vessels underwent ECG-gated magnetic resonance (MR) imaging using the multisectional spin-echo technique (0.35 Tesla). The ability to define segmental anatomy and intracardiac anomalies on transverse, sagittal, and coronal images was evaluated. MR images were graded as excellent, diagnostic, or nondiagnostic, and MR findings were corroborated by angiography and/or two-dimensional echocardiography. Studies that were considered to be excellent or diagnostic were obtained in 96% of the cases. Visceroatrial situs, the type of ventricular loop, and the relationship of the great vessels could be identified in all patients with studies encompassing the entire heart. Forty-four of 47 abnormalities at the level of the great vessels were identified with MR, including coarctation of the aorta and vascular rings. MR showed 32 of 35 ventricular abnormalities; 2 small ventricular septal defects and 1 Ebstein anomaly were not demonstrated. All of the abnormalities at the atrial level and those of systemic and pulmonary venous return were seen on MR images. Complex cardiac anomalies, such as single ventricles, and the status of the pulmonary arteries were clearly demonstrated, and a good assessment of total and palliative postoperative anatomy was provided.

Adolescent↗
PubMed1986

Pulsed Doppler findings in patients with coarctation of the aorta.

We used combined two-dimensional and pulsed Doppler echocardiography to examine 37 infants and children with coarctation of the aorta and 19 normal subjects. The ages ranged from 1 day to 16 years. We compared the differences between the Doppler flow signal from the ascending aorta and the descending aorta below the coarctation in each patient, as well as the differences between the corresponding flow signals in the aorta of patients with coarctation and normal subjects. Six variables were measured from each Doppler signal: acceleration slope (peak rate of acceleration), acceleration time (time from onset of flow to the peak systolic frequency), antegrade flow time, peak systolic frequency, peak velocity of flow, and deceleration slope (peak rate of deceleration). In patients with coarctation, each of these variables was significantly different in the descending aorta compared with the ascending aorta. There was a decrease in the acceleration slope (14 +/- 13 vs 87 +/- 67 kHz/sec) (mean +/- SD), peak systolic frequency (1.8 +/- 1.0 vs 5.2 +/- 1.9 kHz), peak velocity of flow (0.70 +/- 0.40 vs 1.4 +/- 0.44 m/sec), and deceleration slope (11 +/- 11 vs 27 +/- 12 kHz/sec). There was also a prolongation of the acceleration time (140 +/- 50 vs 88 +/- 22 msec) and antegrade flow time (330 +/- 120 vs 270 +/- 50 msec). In addition, these variables in the descending aorta of patients with coarctation were significantly different from those in the descending aorta of normal subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1985

Recognition of fetal arrhythmias by echocardiography.

Fetal arrhythmias were detected in 33/198 high risk pregnancies from 21 weeks to term. Using the two-dimensional echocardiographic image of the fetal heart as a guide, the M-mode beam was directed to define the motion of the ventricular and atrial walls and atrioventricular valve or semilunar valves. Atrial contraction was defined either by the atrial wall motion or from the A-point of the atrioventricular valve. Ventricular contraction was defined by closure of the atrioventricular valve (C-point), the onset of ventricular wall contraction, or from the semilunar valve opening. Ladder diagrams of the sequence of atrial and ventricular activation were constructed to define the temporal sequence of these events. Premature atrial contractions were present in 12. In one fetus this arrhythmia converted into supraventricular tachycardia while in the other 11 fetuses the course was benign. Two fetuses had premature ventricular contractions. Supraventricular tachycardia was noted in five fetuses. One with hydrops at 29 weeks returned to sinus rhythm following maternal administration of procainamide. A second hydropic fetus with paroxysmal atrial tachycardia and hydrops failed to respond to digitalis, propranolol, procainamide, verapamil, or amiodarone, and died shortly after cesarean section. Two mature fetuses had tachycardia close to term and were treated after cesarean section. One fetus with runs of atrial tachycardia died in utero. Three fetuses had complete heart block, two of whom were from mothers with connective tissue diseases. In four fetuses, there was bradycardia of less than 100/minute lasting more than 30 seconds, but these episodes disappeared in 2 minutes.(ABSTRACT TRUNCATED AT 250 WORDS)

Arrhythmias, Cardiac↗
PubMed1985

Echocardiographic techniques for assessing normal and abnormal fetal cardiac anatomy.

Diagnostic quality images of the fetal heart in utero can be obtained as early as 18 to 20 weeks of gestation. The cardiac structures can be imaged primarily by cross-sectional echocardiography and augmented by a combination of simultaneous M-mode echocardiography and range-gated pulsed Doppler ultrasonography. Cross-sectional images from planes through the fetal heart equivalent to planes that can be obtained after birth can be generated in utero. In a study of 168 pregnancies, 10 structural cardiac abnormalities have been defined. These abnormalities and others that have been reported indicate the potential for in utero cardiac diagnosis. The recognition of structural congenital heart disease in utero has been helpful in genetic counseling, planning the method of labor and delivery and making decisions regarding termination of pregnancy and planning postnatal care. Fetal echocardiography offers the potential to change the pattern of health care delivery to those with suspected congenital heart disease.

Echocardiography↗