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Biomedical subjects

H D Allen

Publications and source records attributed to H D Allen.

At least 127 records · Page 7Linked to original sources
PubMed1982

Two dimensional echocardiography and intravenous digital video subtraction angiography for diagnosis and evaluation of double aortic arch.

Two infants and one 7 year old child with double aortic arch are described in whom subcostal two dimensional echocardiography identified the bifurcation of the aorta high within the thorax and imaged the proximal portions of the right and left aortic arches. In one of the infants and in the 7 year old child, the diagnosis was confirmed using intravenous digital video subtraction angiography, thus avoiding aortography and permitting accurate evaluation of the anatomic features. All cases were confirmed surgically. If X-ray examination after barium swallow and clinical history are suggestive of double aortic arch, two dimensional echocardiography is useful in verifying this possibility. Intravenous digital video subtraction angiography provides the capability for precise documentation of the anatomic features.

Angiography↗
PubMed1982

Two dimensional Doppler echocardiographic/M mode echocardiographic and phonocardiographic method for study of extracardiac heterograft valved conduits in the right ventricular outflow tract position.

Significant concern exists over the long-term results of right ventricular outflow tract repair using heterograft valved conduits. Because these conduits and valves are difficult to image using ultrasound, a serially applicable two dimensional Doppler echocardiographic, M mode echocardiographic and phonocardiographic method for noninvasive investigation was developed and applied in 15 children. The method provides two dimensional echocardiographic imaging of valve contour and motion, as well as M mode and phonocardiographic analysis and quantitative range-gated Doppler information about the timing of flow through the conduit. Conduit diameter in two dimensional echocardiographic images correlated well with known conduit size (r = +0.96). A thickened and stenosed heterograft valve was predicted in two patients before hemodynamic investigation. This new method provides serially obtainable information to aid in the management of children and infants with a valved conduit placed for repair of congenital heart malformations and aids in planning the timing of hemodynamic follow-up studies.

Adolescent↗
PubMed1982

Effect of beam directional alterations on left ventricular shortening fraction.

In this study, the dependence on beam direction of the echocardiographically derived fractional shortening of the left ventricular minor axis was evaluated. A directionally oriented, steerable cursor was used to select M-mode lines from a 2-dimensional image at the chordal level. Seven M-mode traces were derived from each image, 1 along the true ventricular meridian and 3 at known deviations on either side of the meridian. M-mode traces, thus derived, all appeared acceptable for measuring wall or cavity dimensions. Results indicate a progressive increase in shortening fraction (p less than 0.05) for deviations more than 25% of the distance between the meridian and the lateral or medial papillary muscle heads. Decreases in left ventricular dimensions in diastole and systole with progressive deviation from the meridian accounted for the decrease in shortening fraction. Spatial orientation is required for reproducible shortening fraction measurements.

Adolescent↗
PubMed1982

Cross-sectional echocardiographic diagnosis and subclassification of univentricular hearts: imaging studies of atrioventricular valves, septal structures and rudimentary outflow chambers.

We reviewed anatomic observations (surgical or autopsy), angiograms and echocardiograms from 44 patients with documented univentricular hearts. Thirty-three patients had univentricular heart of left ventricular type with an outflow or rudimentary chamber. Five had univentricular heart of right ventricular type, and six had univentricular heart of indeterminate types without a rudimentary chamber. Univentricular heart was correctly diagnosed by two-dimensional echocardiography in all but two of the 44 patients, including 25 of 27 double-inlet univentricular hearts, all five with absent left and all 12 with absent right atrioventricular connection. One of the two blind trabecular pouches was missed on echocardiography; the other was not seen on the angiogram but was present at autopsy. In 30 of 33 patients, univentricular heart of left ventricular type was correctly identified by imaging an anterosuperior and leftward or rightward outlet chamber, and in four of five patients with univentricular heart of right ventricular type, the anomaly was correctly identified by imaging the inferior and posterior position of the rudimentary outflow chamber near the crux of the heart. Two-dimensional echocardiography provides detailed analysis of atrioventricular connections, main chamber morphology, and rudimentary chamber size and position of noninvasive diagnosis and anatomic subclassification of univentricular hearts.

Adolescent↗
PubMed1982

Serial two-dimensional echocardiography in Duchenne muscular dystrophy.

Patients with Duchenne muscular dystrophy (DMD) are known to have progressive epicardial fibrosis of the free wall of the left ventricle, but standard noninvasive M-mode echocardiographic tests of left ventricular function are relatively insensitive detectors of this cardiomyopathy. We therefore used two-dimensional echocardiography to record three short axis levels of the left ventricle in 13 Duchenne patients. Serial studies were separated by 2 years for most patients. The two-dimensional echocardiographic technique allows qualitative evaluation of segmental contraction of the left ventricle. Four general principles were found during this study: (1) Obvious contraction abnormalities of the left ventricle were present in most patients with DMD. (2) In most patients, the contraction deficit was first noted in the left ventricular posterior free wall behind the mitral valve. (3) Once a contraction deficit was observed, the area of abnormal contraction progressed inferiorly to include additional areas of the left ventricular posterior free wall. (4) Standard M-mode left ventricular function techniques were unreliable for detecting individuals with segmental contraction abnormalities.

Adolescent↗
PubMed1982

Aortic thrombosis in a neonate: failure of urokinase thrombolytic therapy.

Complete aortic occlusion at L2-L3 occurred in an 11-day-old male with hypernatremic dehydration. Attempted thrombolytic therapy using intraarterial urokinase was unsuccessful in inducing either a systemic hyperfibrinolytic state or lysis of the clot. The infant's plasma plasminogen level was low (50-75% of adult levels) and neither fresh frozen plasma nor cryoprecipitate infusion provided adequate plasminogen replacement. Thrombolytic therapy failure was due in part to inadequate generation of plasmin. Alternative means of lytic therapy will need to be devised for this age group.

Aortic Diseases↗
PubMed1982

Residual shunting in the early postoperative period after closure of atrial septal defect: echocardiographic comparison of patch materials.

Residual shunting after surgical closure of septal defects is a common postoperative complication. In this study, contrast echocardiography was used to assess the effect of different surgical patch materials on early postoperative residual shunting. The study consisted of 44 patients (aged 3 days to 64 years) with simple or complex atrial septal defects. Total pulmonary-to-systemic flow ratios ranged form 1.8:1 to 4.0:1. Three methods were used to close the atrial septal defects: primary suture closure (n = 7), patching with thin, knit Teflon fabric (n = 13), and patching with thicker, low porosity, knit Teflon fabric (n = 24). Contrast echocardiographic injections were performed through central venous and left atrial lines positioned at operation for monitoring purposes. Ten of the 44 patients had residual shunts. In five of them, daily contrast studies showed progressive diminution in shunting with eventual resolution, but in the other five patients, shunting persisted beyond the first 5 postoperative days. Three of the latter five required reoperation for actual residual anatomic defects. No patient whose atrial septal defect was closed by either direct suture or thick, low porosity Teflon fabric had shunting detected at any time postoperatively. Our data confirmed temporary leakage across newly implanted intracardiac patches. However, shunts that persist beyond the first postoperative week indicate true anatomic residua and not porous patch material. If a patient's recovery is complicated, use of contrast echocardiography can determine whether a residual shunt is a causative factor. In patients with complex lesions in whom continued shunting during the early postoperative period may cause serious hemodynamic consequences, heavier, low porosity patch material can be useful.

Adolescent↗
PubMed1981

Accuracy of two-dimensional echocardiography in the detection of aneurysms of the ventricular septum.

Eight children with angiographically proven aneurysm of the membranous ventricular septum (AVS) associated with ventricular septal defect were studied by real-time cross-sectional echocardiography. A curvilinear, sickle (dome-shaped), or irregular echo arising from the interventricular septum and bulging toward the right ventricle in systole was visualized in all patients. This finding was detected in 7 of 8 long axis views, 5 of 8 short axis views, 5 of 7 apex four-chamber views, and 4 of 7 subcostal four-chamber views. In addition, real-time cross-sectional echocardiograpic studies were performed in 40 patients with angiographically proven membranous ventricular septal defect without AVS; in only one patient was the abnormal echo suggesting aneurysm of the ventricular septum detected in the long axis and apex four-chamber views. Our echo study suggests that two-dimensional echocardiography has acceptable specificity for the diagnosis of AVS.

Child↗
PubMed1981

Range gated Doppler ultrasound detection of contrast echographic microbubbles for cardiac and great vessel blood flow patterns.

Ultrasonic contrast techniques allow tracking of blood flow in patients with cardiac malformations. One problem often encountered in M-mode contrast is inability to generate adequate microbubbles for recording. Theoretically, echo Doppler should be more sensitive for detection of microbubbles. To test this hypothesis, results of 75 saline injections were studied at catheterization in 16 patients by simultaneously recording contrast M-mode and echo Doppler studies. For this part of the investigation, an ATL 500 system was utilized. The M-mode of this system was found to provide identical information to that of SmithKline. Records were evaluated without identification of the patient. In all instances (n = 20) in which microbubbles were not expected on the basis of flow patterns, none were detected by Doppler. One error occurred for M-mode. Contrast in the direction of flow was visualized in 50 of 55 injections by echo Doppler. In these, a frequency dispersion was present, but even more striking was a marked rise in the time interval histographic input signal strength indicator. Only 40 of 55 simultaneous M-mode echoes showed a contrast effect (p less than 0.05). Doppler microbubble detection was usually represented by a much stronger signal than was M-mode contrast. This investigation demonstrates that range gated Doppler is an effective method for microbubble detection.

Child↗
PubMed1981

Factors affecting real-time, cross-sectional echocardiographic imaging of perimembranous ventricular septal defects.

Recent studies suggest good prospective accuracy for two-dimensional echocardiographic imaging of ventricular septal defects (VSD). We obtained two-dimensional images with high-frequency, high-resolution scanners from 36 patients proved by cardiac catheterization to have perimembranous VSD. In 20 patients, the VSD was an isolated lesion and in 16 it was associated with other forms of heart disease. VSDs were imaged in long-axis, apical four-chamber and subcostal echocardiographic views. The smallest VSD imaged was 2 mm in diameter on echo; the largest, 23 mm. The imaged size of VSDs was larger at end-diastole than at end-systole by paired t test on all views (all p less than 0.005). VSD size also varied between views, with no predictive relationship except between apical and subcostal four-chamber views in diastole (r = 0.71, p less than 0.005). This agreed with qualitative direct observations of an ellipsoid or irregularly shaped VSD in operated patients. Echocardiographically measured VSD size normalized for either aortic root size or for patient weight could be used to separate isolated VSDs with large shunts (Qp/Qs greater than 2:1) from those with small shunts. Review of 250 two-dimensional echocardiographic studies from patients proved not to have a VSD revealed 28 planes of imaging with false-positive VSD. None of the false-positive VSDs was imaged consistently on all views. Additionally, a "T" artifact (broadening of septal edges around a VSD) has been found to be a reliable marker of true VSD imaging. To best quantify VSD size and to avoid false-positive diagnoses, it is necessary to use multiple views and to consider the marked changes in VSD size that occur between diastole and systole.

Adolescent↗
PubMed1981

Drug abuse and the private practice of medicine.

Data from a survey of private physicians in New Orleans, Louisiana, conducted in order to determine the extent to which they have encountered patients with symptoms related to drug abuse, is presented. A surprisingly high incidence is noted (median of 5.0 cases in the last year) with an especially large number of minor tranquilizer problems of particular interest. Patients tend to be White, old, and female when compared with populations of individuals usually considered more prone to drug problems. It is suggested that this high incidence indicates the need for drug abuse to be included more extensively in the training of medical personnel.

Adolescent↗
PubMed1980

Use of health education and attempted dietary change to modify atherosclerotic risk factors: a controlled trial.

The purpose of this investigation was to determine if nutrition education regarding atherosclerotic risk factors and dietary changes that might reduce these factors, taught in an elementary school setting, would cause children to alter their diets in a way that would produce a significant reduction in risk factor values as compared to a control group. Serum cholesterol, blood pressure, height, weight, and skinfold thickness were the evaluated variables. Sixty-eight children who had been enrolled in the intervention program had complete data at the termination of the 3-year study. The major control group consisted of 23 children from a different school. Additional control groups were formed to provide information regarding general population changes in the risk factors during the time span of the study and to investigate values of children who did not complete the entire program. The results showed no major significant changes for these variables as compared to the control group or the preintervention values of the intervention population. As expected, the population had an initially relatively low risk. Tracking of these variables over 3 years showed results similar to those of other investigations that did not include intervention. It is concluded that, although the education proved effective by cognitive testing, the methodology used in this study was ineffective in reducing significantly the above risk factors of the population investigated.

Arteriosclerosis↗