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Biomedical subjects

H D Allen

Publications and source records attributed to H D Allen.

At least 163 records · Page 9Linked to original sources
PubMed1978

Successful palliation using partial cardiopulmonary bypass in a two-day-old infant with type B interruption of the aortic arch.

Partial cardiopulmonary bypass from the pulmonary artery to the descending aorta was used successfully for resuscitation and aortic arch reconstruction in a 2-day-old infant with type B interrupted aortic arch. Partial cardiopulmonary bypass interrupted the fatal progression to acidosis and death caused by hypoperfusion of structures distal to the ductus arteriosus in this "ductus dependent" infant, and this approach provided time for an accurate dissection and anastomosis. The natural history, pathophysiology, and currently available surgical alternatives are considered in suggesting a possible role for partial bypass in the treatment interrupted aortic arch.

Acidosis↗
PubMed1977

Neonatal hyperthyroidism and heart failure. A differential approach.

Congestive heart failure in neonatal thyrotoxicosis is attributed to sympathetic overstimulation of the myocardium with resulting high-output cardiac failure. An additional case of neonatal thyrotoxicosis with congestive heart failure is discussed; three possible causes (thyrotoxicosis, maternal propranolol therapy, and ventricular septal defect) were present. Along with the usual procedures, the echocardiogram is of value in separating these factors. In addition, we discuss the potential dangers to the newborn of a mother receiving long-term propranolol hydrochloride therapy during pregnancy.

Digitalis Glycosides↗
PubMed1977

Echocardiographic detection and management of patent ductus arteriosus in neonates with respiratory distress syndrome: a two-and one-half year prospective study.

A prospective 2 1/2 year study of 50 infants with combined respiratory distress syndrome (RDS) and patent ductus arteriosus (PDA) was undertaken to determine whether echocardiographic measurements combined with clinical assessment could be used to select those infants who needed cardiac treatment. From a pilot study, criteria were adopted to use digoxin in the treatment of infants with evidence of congestive cardiac failure and/or a left atrial dimension 1.5 times normal size, and to ligate the PDA in those with unremitting congestive cardiac failure and a left atrial dimension persistently twice normal. Left atrial, left ventricular, and aortic dimensions, left atrial to aortic ratio, and mean Vcf were echocardiographically determined. Forty-six per cent of the 50 infants with PDA required digoxin administration, and 18 per cent of the total group was operated. The long-term mortality for the total group was 12 per cent (6 of 50) and mortality was 33 per cent (3 of 9) for the operated group. Results showed that absolute left atrial dimension, particularly if recorded in two dimensions, most accurately predicted those infants who would develop congestive cardiac failure or failure that would become medically unmanageable.

Aorta↗
PubMed1977

Echocardiographic spectrum of mitral valve motion in children with and without mitral valve prolapse: the nature of false positive diagnosis.

To examine problems in echocardiographic diagnosis of mitral valve prolapse, multiple crystal cross-sectional echocardiography and single crystal recordings derived from the multiple crystal array were used to study 45 clinically normal children aged 3 to 15 years (Group A), 26 children aged 2 to 10 years with known mitral valve prolapse (Group B), 12 children with a catheterization-proved large left to right shunt at the ventricular level (Group C) and 8 children with catheterization-proved left ventricular outflow tract obstruction (Group D). Children in Groups A and B were not studied hemodynamically. Children in Groups C and D had no evidence of mitral valve prolapse on angiography and were studied echocardiographically to determine the effect of changes in ventricular shape on the patterns of mitral valve motion. In the real time cross-sectional studies, normal patients demonstrated a spectrum of mitral valve motion in which the bodies of the anterior and posterior leaflets became slightly horizontal with systolic ejection. The mitral apparatus assumed a curvilinear funnel shape. Arching of the leaflets into a horizontal configuration was more striking in the presence of either left ventricular dilatation in left to right shunt or involvement of the anterior mitral anulus in subaortic stenosis (two patients) and was associated with false positive M mode tracings suggesting mitral valve prolapse. This latter configuration was easily differentiated from the superior motion of the body of the leaflets in true prolapse. Studies of single crystal M mode recordings derived form the cross-sectional array in known locations from six normal patients revealed M mode patterns of pseudoprolapse in tracings derived from the leaflet body and patterns of normal motion at the free edge. In contrast, superior-posterior prolapse visualized in cross-sectional studies in patients with the click-murmur syndrome was associated with abnormal M mode recordings from all parts of the leaflet, including the free edge, although the abnormalities were most striking in tracings derived from the leaflet body. The M mode echocardiographic findings of mitral valve prolapse in both normal patients and patients with the click-murmur syndrome were dependent upon transducer angulation and the portion of the valve examined. The critical differentiation of the spectrum of normal valve motion from prolapse requires careful evaluation of echoes from the free edge of the leaflet where the posterior and anterior leaflet echoes coapt in early systole.

Adolescent↗
PubMed1977

Septum primum defect repair.

Two technical maneuvers in septum primum defect repair have resulted in improved mitral valve function and security against heart block. One maneuver, critical to restoring mitral competence, is accurate reconstruction of the leading edge of the mitral valve. A second maneuver, suturing the septal defect patch at its inferior aspect to the mitral valve near the annulus instead of to the inferior septal defect margin or to the tricuspid annulus, eliminates the hazard of atrioventricular node or bundle injury.

Heart Block↗
PubMed1977

A quantitative echocardiographic study of champion childhood swimmers.

An echocardiographic evaluation of 77 members of a championship childhood swim team showed dimensional variations from normal in most athletes. Cardiac walls were thicker than the 95th percentile of normal: right ventricular anterior wall exceeded the 95th percentile in 100%, interventricular septum in 83% and left ventricular posterior wall in 91%. The left ventricular and left atrial cavities in diastole had mean values at the 50th percentile of normal but showed considerable scatter. The left ventricular cavity in systole had a mean value less than the 5th percentile of normal and also showed wide scatter. The aortic root and the aortic intercusp dimension exceeded the 95th percentile of normal in most subjects, 74% and 77%, respectively. No correlation existed between the coach's estimate of championship ability and echocardiographic wall or chamber sizes. Children who participate extensively in athletic training programs such as swimming may have echocardiograms which are quantitatively different from those of nonathletic younsters.

Adolescent↗
PubMed1977

Suprasternal notch echocardiography. Assessment of its clinical utility in pediatric cardiology.

Echocardiographic suprasternal relationships of the transverse aortic arch (TAA), right pulmonary artery (RPA) and left atrium (Y' LAD) were validated and angiographic-echocardiographic measurement correlations were made for each structure. Normal values were determined with respect to body surface area. In normals, regardless of age or body size, mean dimensional TAA/RPA ratio was 1.2:1 and Y' LAD equaled the anterior-posterior, or Z axis, left atrial dimension (Z LAD)- TAA/RPA ratio was increased in aortic stenosis and tetralogy of Fallot and was decreased in ventricular septal defect, atrial septal defect and pulmonary stenosis. Ratio did not correlate with lesions severity as assessed by cardiac catheterization except in pulmonary stenosis. Discrepant Y' LAD values (usually increased Y' LAD and decreased Z LAD) occurred in children with various forms of heart disease. Some had sternal compression but others had normal chests. Children with pectus excavatum showed similar compression. These findings underscore the need for incorporation of a suprasternal examination into the standard echocardiographic examination of children.

Adolescent↗
PubMed1977

Real-time cross-sectional echocardiographic diagnosis of coarctation of the aorta: a prospective study of echocardiographic-angiographic correlations.

Real-time cross-sectional echocardiographic sector scan examinations were performed from a suprasternal notch location to image aortic anatomy in 15 children (ages 1 day to 21 years) who were subsequently shown at cardiac catheterization to have coarctation of the descending thoracic aorta. The resulting echocardiographic images of the ascending, transverse and descending aorta imaged juxtaductal coarctation in all 15 patients. Echocardiography predicted discrete coarctation of the aorta in eight, isthmic hypoplasia in two, hourglass type coarctation deformities in three and longer segment coarctation in four patients. Catheterization and angiography confirmed all of these anatomic observations. The control group, 100 patients with congenital heart disease but without angiographic coarctations, included four patients with right-sided aortic arch and six patients with dextrocardia. The ascending, transverse and descending aorta were adequately imaged in 94 of these and no descending aortic abnormalities were noted. This study shows the potential utility of cross-sectional echocardiography for the noninvasive precatheterization or preoperative assessment of coarctation of the aorta in children and critically ill newborns.

Adolescent↗
PubMed1977

The utility of contrast echocardiographic techniques in the care of critically ill infants with cardiac and pulmonary disease.

In order to assess the utility of contrast M-mode echocardiography in an intensive care nursery population of critically ill newborns with cardiac and pulmonary disease and to validate contrast echo methods, we performed 200 serial contrast echoes on 40 infants via umbilical arterial or venous catheters which had been placed into these infants for clinical indications. The resulting contrast echoes recorded from the precordium or the suprasternal notch allowed the delineation of intra- and extracardiac right-to-left and left-to-right shunting patterns. Patterns identified and validated by cardiac catheterization (in cardiac patients) were: right-to-left atrial shunts, right-to-left ventricular shunts, and left-to-right patent ductus arteriosus shunts. The studies were without complication. Serial application of these echocardiographic techniques was extremely important in assessing changing physiology in these neonates. Contrast echocardiography adds physiologic flow information to the anatomical information available from M-mode echoes and is quite important in the diagnosis and sometimes in the management of critically ill newborns.

Arteries↗
PubMed1976

Echocardiographic detection of large left to right shunts and cardiomyopathies in infants and children.

Diagnostic separation of infants with signs of cardiac failure (hypoglycemia, sepsis, myocarditis, hypoxemia) but no congenital cardiocirculatory malformation from those with a large left to right shunt is crucial in newborn management. Echocardiographic studies of 218 infants and children allowed group separation and distinction from normal by the assessment of mean velocity of circumferential fiber shortening (Vcf) and the ratio of left atrial to aortic root diameter at end-systole (LA/Ao). In normal premature and full-term infants, Vcf (1.51 +/- 0.04 [mean +/- standard error]) was significantly lower than in infants with a large shunt (2.12 +/- 0.08, P less than 0.01) and higher than in infants with nonstructural heart disease (1.18 +/- 0.06, P less than 0.001). LA/Ao ratios were comparable in the groups with a large shunt and nonstructural heart disease (1.14 +/- 0.1 and 1.26 +/- 0.2, respectively) and were significantly higher in both groups than in normal subjects (0.77 +/- 0.01, P less than 0.001). Similar echocardiographic distinctions could be made when 10 older children (aged 2 to 10 years) with cardiomyopathy were compared with 45 normal older children. Serial determination of these variables was of major assistance in patient management.

Cardiomyopathies↗
PubMed1976

The asymmetrically hypertrophied septum. Further differentiation of its causes.

Fifty-eight subjects with echocardiographic criteria for an abnormal septal to left ventricular posterior wall ratio were studied. Echocardiographic findings were related to clinical cardiac status. Abnormal ratios were found in normal children and in children with a variety of cardiac lesions, only one of which was obstructive or non-obstructive cardiomyopathy. In those without cardiomyopathy, the abnormal ratio usually resolved by one or two years of age. Persistence of abnormal ratio usually occurred in patients with increased right ventricular anterior wall thickness or idiopathic hypertrophic subaortic stenosis. The cause of abnormal ratio is multifactorial.

Cardiomyopathy, Hypertrophic↗
PubMed1976

Mitral valve prolapse in children: a problem defined by real-time cross-sectional echocardiography.

The cross-sectional echocardiographic features of mitral valve prolapse were defined in 26 children (ages 2-18 years) using a real-time, multiple-crystal ultrasound scanner. In each patient the physical findings of the mitral valve click-murmur syndrome were present and mitral valve prolapse had been diagnosed previously by conventional single crystal echocardiography. Mitral prolapse occurred in a familial setting in eight patients and was associated with the Marfan syndrome in five. Real-time two-dimensional echocardiography uniformly disclosed maximum mitral arching and the superior-posterior prolapse. These visual observations were confirmed by M-mode recordings derived from single elements within the array of 20 crystals. The method allowed a complete M-mode description of the phasic motion of the entire mitral apparatus and observations of the spectrum of prolapse from discrete late systolic prolapse to "hammock-like" holosystolic prolapse. Further, the recording of multiple systolic M-mode lines occurred when the ultrasound beam intersected the arched leaflets more than once. Pseudosystolic anterior motion was observed often and resulted clearly from a superimposition of echoes from the mitral annulus and from the posterior-superiorly arched prolapsed leaflets. A major finding in 22 patients was the association with prolapse of biconvex enlargement of the aortic sinuses of Valsalva and a significant increase in the diameter of the aortic root. Aortic root dilatation was most marked in, but not confined to, patients with the Marfan syndrome and was a prominent finding in six patients with minor musculoskeletal abnormalities. The presence of aortic root dilatation in children with normal body habitus raises important questions concerning the generalized nature of an abnormality of cardiac connective tissue in patients with mitral prolapse. The cross-sectional approach significantly enhances the noninvasive evaluation of mitral valve prolapse and provides an explanation for many of the single crystal observations reported previously.

Adolescent↗
PubMed1975

Pediatric echocardiography: a review of its clinical utility.

Echocardiography is a new noninvasive tool which provides real-time motion visualization of intracardiac structures for the evaluation of anatomy and physiology in patients with congenital heart disease. This paper is presented to acquaint the pediatrician with the utilization and potential of this technique as practiced by pediatric cardiologists. A discussion of principles of physics and instrumentation in echocardiography is followed by a description of normal echocardiographic anatomy. Specific malformations which can be diagnosed reliably by this technique include: hypoplastic left heart syndrome, transposition of the great vessels, tetralogy of Fallot, idiopathic hypertrophic subaortic stenosis, mitral valve prolapse, and pericardial effusion. In addition, the evaluation of patients with atrial septal defects and patent ductus arteriosus is discussed. New advances in instrumentation and their potential impact in pediatric cardiology are reviewed.

Aorta↗
PubMed1975

Great vessel, cardiac chamber, and wall growth patterns in normal children.

The purpose of this study was to establish normal echocardiographic measurements of valvular motion, cavity dimensions, great vessel diameters, and right, left and septal wall thicknesses of children ranging in size from infants to full growth. The study group was composed of 205 normal, healthy children for whom echocardiograms and subsequent measurements were performed in a standardized manner. The following measurements were performed: left ventricular end-diastolic and end-systolic dimension, right ventricular end-diastolic cavity dimension, right ventricular end-diastolic anterior wall thickness, left ventricular end-diastolic posterior wall thickness, ventricular septal end-diastolic thickness, maximal left atrail dimension, end-diastolic aortic and pulmonary artery diameter, end-diastolic cardiac and septal depth, maximal aortic leaflet separation, and maximal anterior mitral and anterior tricupsid amplitude. Data are grouped into the fifth, fiftieth, and ninety-fifty percentiles according to body surface area. These graphs allow measurements of a single patient to be compared to normal measurements of individuals with similar body surface area.

Aorta↗