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Biomedical subjects

R H Anderson

Publications and source records attributed to R H Anderson.

At least 253 records · Page 14Linked to original sources
PubMed1991

Aortic atresia with aortopulmonary window and interruption of the aortic arch.

The cross-sectional echocardiographic and postmortem appearances of the heart from a patient with the rare association of aortic valve atresia, aortopulmonary window, and interrupted aortic arch are described. Differentiation of this anomaly from truncus arteriosus with interrupted aortic arch is important.

Aorta, Thoracic↗
PubMed1991

Tetralogy of Fallot.

Explore the source record for details and available documents.

Heart Septal Defects, Ventricular↗
PubMed1991

Fibrous skeleton and ventricular outflow tracts in double-outlet right ventricle.

Twenty-four hearts in which both great arteries arose from the right ventricle were studied to establish variations present within the fibrous skeleton and infundibular morphologies. Variations were also noted in the location of the ventricular septal defect and measurements were obtained of the outlet septum and the circumferences of the arterial valves. Completely muscular subarterial infundibulums were present in only 9 (37.5%) of the hearts, with varying degrees of fibrous continuity between the leaflets of the arterial and atrioventricular valves in the remainder. The aorta was rightward and posterior in 12 (50%) of the hearts, and subaortic and subpulmonary ventricular septal defects were present in equal numbers in this group. No subaortic defects were present when the aorta was side-by-side and right-sided. No subpulmonary defects were present in hearts with a posterior aorta. The mean ratio of 0.91 +/- 0.36 for the subpulmonary to subaortic length of the outlet septum was significantly less than the value of 1.54 +/- 0.41 noted previously in hearts with tetralogy of Fallot (p less than 0.001).

Aortic Valve↗
PubMed1991

The myth of the aortic annulus: the anatomy of the subaortic outflow tract.

Surgical repair of the small aortic root is limited in part by the very structure of the outflow tract from the left ventricle. The root is not constructed on the basis of a ringlike annulus supporting the leaflets of the aortic valve. The only truly circular structure within the outflow tract is the junction of the aortic wall with the underlying ventricular structures, themselves partly muscular and partly fibrous. This circular ventriculoarterial junction is crossed by the semilunar attachments of the leaflets of the aortic valve, producing an interlinking arrangement between the expanded aortic sinuses and three triangles of fibrous tissue placed beneath the apexes of the commissures between the valve leaflets. The triangles form extensions of the left ventricle that are related, in part, to the pericardial cavity surrounding the heart. The arrangements of the attachment of the leaflets in malformed valves with two (or only one) effective leaflets are highly abnormal, although these valves are usually produced on the template of three aortic sinuses. The valve with two leaflets rarely gives problems during childhood. In valves producing "critical stenosis", there is usually only one effective leaflet, a condition due to incomplete liberation of two of the anticipated three commissures. Detailed study shows that, in these malformed hearts, the attachment of the leaflets is much more annular than in normal valves, with inadequate formation of the fibrous triangles.

Aortic Valve↗
PubMed1991

Ventricular septal defects in a family of Yucatan miniature pigs.

We have studied the hearts from a colony of Yucatan miniature pigs with spontaneously occurring congenital defects. Ventricular septal defect was encountered in 57 of 81 neonates from 15 consecutive litters. Of 73 hearts preserved for morphological assessment, 52 were found to have defects within the ventricular septum remarkably similar to those observed in humans with deficient ventricular septum. The defects, including 3 which had closed spontaneously, were perimembranous in 34, muscular in 12 and doubly committed and juxtaarterial in 6 hearts. Atrial septal defects were found in 12 of the 52 hearts with deficient ventricular septation; only 1 atrial septal defect was seen among 21 hearts with an intact ventricular septum. Anomalies of the aortic arch were associated with ventricular septal defect in 2 cases; 1 with a solitary arterial trunk and one with hypoplasia of the aorta and patent arterial duct. All these findings are replicated in human hearts. This strain of pig provides an ideal large animal model for morphologic and genetic investigations concerning the details of ventricular septation, including potential mechanisms of late spontaneous closure.

Animals↗
PubMed1991

Pathologic spectrum of malformations of the tricuspid valve in prenatal and neonatal life.

The morphologic spectrum of malformations of the tricuspid valve in 14 fetal and 5 neonatal heart specimens is described. Echocardiography during fetal life had revealed the valvular malformations along with dilation of the right-sided chambers of the heart and atrioventricular (AV) valve incompetence. This functional impairment reflected either Ebstein's malformation (10 cases) or dysplasia of valve leaflets having a normal junctional attachment (9 cases). The right atrium and right ventricle were markedly enlarged, and heart weight was increased to 181% (median) and 179% (median) in the groups with Ebstein's malformation and valvular dysplasia, respectively. In contrast, lung weight was in the lower range of normal, showing a decrease of 67% (median) in patients with Ebstein's malformation and of 43% (median) in those with valvular dysplasia. One ventricular septal defect and six atrial septal defects were noted in each group. Severe obstruction at the level of the pulmonary valve was seen in 40% of the group with Ebstein's malformation and in 66% of those with valvular dysplasia. The most important factor in the particularly poor prognosis in these patients is the incompetence of the tricuspid valve, leading to right atrial enlargement and subsequent pulmonary hypoplasia. No significant difference was found between the pathologic features of fetal and neonatal hearts and no features that might have prompted the valve to become regurgitant during fetal life were identified.

Abnormalities, Multiple↗
PubMed1991

Double-outlet right ventricle: morphologic demonstration using nuclear magnetic resonance imaging.

Sixteen patients with double-outlet right ventricle, aged 1 week to 29 years (median 5 months), were studied with a 1.5 tesla nuclear magnetic resonance (NMR) imaging scanner. Two-dimensional echocardiography was performed in all patients. Thirteen patients underwent angiography, including nine who underwent subsequent surgical correction. Three patients underwent postmortem examination. Small children and infants were scanned inside a 32 cm diameter proton head coil. Multiple 5 mm thick sections separated by 0.5 mm and gated to the patient's electrocardiogram were acquired with a spin-echo sequence and an echo time of 30 ms. A combination of standard and oblique imaging planes was used. Imaging times were less than 90 min. The NMR images were technically unsuitable in one patient because of excessive motion artifact. In the remaining patients, the diagnosis of double outlet right ventricle was confirmed and correlated with surgical and postmortem findings. The NMR images were particularly valuable in demonstrating the interrelations between the great arteries and the anatomy of the outlet septum and the spatial relations between the ventricular septal defect and the great arteries. Although the atrioventricular (AV) valves were not consistently demonstrated, NMR imaging in two patients identified abnormalities of the mitral valve that were not seen with two-dimensional echocardiography. In one patient who had a superoinferior arrangement of the ventricles, NMR imaging was the most useful imaging technique for demonstrating the anatomy. In patients with double-outlet right ventricle, NMR imaging can provide clinically relevant and accurate morphologic information that may contribute to future improvement in patient management.

Angiography↗
PubMed1991

The surgical anatomy of tetralogy of Fallot with pulmonary atresia rather than pulmonary stenosis.

We examined the pertinent surgical features of the anatomy of 56 hearts having tetralogy of Fallot with pulmonary atresia instead of stenosis, or malformations with pulmonary atresia closely related to tetralogy. We took particular cognizance of the pulmonary arterial supply in 15 hearts in which this was derived through systemic-to-pulmonary collateral arteries, dissecting, as far as possible, the bronchopulmonary segmental distribution of the collateral arteries compared to the intrapericardial pulmonary arteries in 11 of these hearts. Two of the hearts had absence of intrapericardial pulmonary arteries, so that a solitary arterial trunk left the base of the heart. Evidence of an atretic subpulmonary infundibulum was found in 40 of the hearts, while such an infundibulum was lacking in the remainder. The pulmonary atresia was muscular in 43 hearts, valvar in 11, while the pulmonary trunk was absent in the other two hearts. In the hearts with collateral arteries, on average 2.6 collaterals were found in each case, varying from two to five per case. Only one of these arose from a brachiocephalic artery, the others all arising from the descending aorta. The distribution of collateral arteries in two cases was remarkably reminiscent of the arrangement of bronchial arteries. As far as could be judged, 16.5 bronchopulmonary segments on average were supplied in each heart, 5.1 exclusively by collateral arteries, 11.8 by intrapericardial pulmonary arteries and an average of 0.64 segments per case having a shared supply.

Collateral Circulation↗
PubMed1991

Left ventricular dysfunction in the fetus: relation to aortic valve anomalies and endocardial fibroelastosis.

OBJECTIVE: To examine the relation between a characteristic form of left ventricular dysfunction in the fetus and abnormalities of the aortic valve and endocardial fibroelastosis of the left ventricle. DESIGN: A retrospective study to examine the correlation between echocardiographic findings in the fetus and postnatal or necropsy findings. SETTING: Tertiary referral centre for fetal echocardiography. PATIENTS: Thirty fetuses showing a characteristic echocardiographic picture of left ventricular dysfunction. MAIN OUTCOME MEASURES: The relation between the prenatal echocardiographic features and the postnatal and necropsy findings. RESULTS: At presentation the size of the left ventricular cavity was normal or enlarged in all cases. The measurements of the orifice of the aortic root and mitral valve were either normal or small for the gestational age. The echocardiographic diagnosis made at presentation was critical aortic stenosis in all cases. At necropsy or postnatal examination the aortic valve was dysplastic and stenotic in 15 cases and the left ventricle had become hypoplastic in one of these. Aortic atresia was present in seven patients, three of whom had a hypoplastic left ventricle. In six patients the aortic valve was bicuspid although not obstructive. One of these patients had hypoplasia of the aortic arch and one had a hypoplastic left ventricle but in the remaining four patients endocardial fibroelastosis of the left ventricle was the only abnormality found. No follow up information was available in two. Of 26 patients for whom there was postmortem information, 24 had evidence of some degree of endocardial fibroelastosis of the left ventricle. Sequential observations showed that five cases developed into the hypoplastic left heart syndrome. CONCLUSIONS: This type of left ventricular dysfunction in the fetus is the result of an overlap of diseases, including primary left ventricular endocardial fibroelastosis, critical aortic stenosis, and the hypoplastic left heart syndrome.

Aortic Valve↗
PubMed1991

Double-inlet ventricle presenting in infancy. II. Results of palliative operations.

The influence of palliation on survival was studied in 191 consecutive infants, presenting at under 1 year of age, with double-inlet ventricle (1973 to 1988, median follow-up 8.5 years). Palliative operations were performed on 154 occasions in 121 patients (63%). Survival after a systemic-pulmonary arterial shunt (n = 57) and banding of the pulmonary trunk (n = 35) was comparable (84% and 77% at 1 year, 62% and 45% at 5 years), but those who underwent repair of aortic arch obstruction fared worse (n = 18, 44% and 22% at 1 and 5 years, p less than 0.001). The remainder did not undergo an operation because of balanced physiology (n = 17, 9% of entire group), complex anatomy (n = 32, 15%), or irreversible low output (n = 19, 12%). Palliative surgery, overall, had a deleterious effect on immediate survival (greater than 1 month relative risk 6.6, p less than 0.001), but, in the survivors, medium-term outcome was improved (greater than 6 months, 0.68, p less than 0.05). This effect was most marked for those undergoing a systemic-pulmonary artery shunt (less than 1 month, 2.52; greater than 6 months, 0.43); by contrast, after banding of the pulmonary trunk, with or without additional repair of the aortic arch repair, medium-term risk was not altered (greater than 6 months, 1.13 and 0.91, respectively). These data will assist the clinician in making decisions concerning the management of infants with double-inlet ventricle and in the judicious use of palliative surgery.

Anastomosis, Surgical↗