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Biomedical subjects

S Y Ho

Publications and source records attributed to S Y Ho.

At least 253 records · Page 14Linked to original sources
PubMed1989

The morphology of the normal aortic valve as compared with the aortic valve having two leaflets.

We studied 30 normal aortic valves and 64 aortic valves with only two leaflets to examine their morphologic components. The components of the aortic valve are the leaflets, the sinuses, and the interleaflet triangles. The first part of our study shows the relationship of these component parts of the normal aortic valve to the other cardiac structures. The second part shows a wide variation in the architecture of valves having two leaflets. Having produced criteria for the number of sinuses and the number of leaflets, we discovered that previous criteria used in the definition of valves with two leaflets are inadequate when the whole valvular complex is considered. Only seven valves in the study have two leaflets supported by two sinuses. The evidence points to the other valves having started with three leaflets but becoming bicuspid during either intrauterine or postnatal life.

Adult↗
PubMed1988

Transluminal balloon dilation of resected coarcted segments of thoracic aorta: histological study and clinical implications.

The effect of experimental balloon dilation on seven excised specimens of classic coarctation was assessed histologically. Widening of the lumen was achieved in all specimens by tears in the vessel wall. The tears extended through the intima in one specimen and through both intimal and medial layers in six specimens. In view of the extent of wall damage, we postulate that there would be serious long-term complications following balloon dilation for the treatment of native coarctation.

Adult↗
PubMed1988

Anomalous origin of single coronary artery in association with pulmonary atresia.

We report a case of pulmonary atresia with intact septum associated with single coronary artery which originated from the pulmonary trunk. The combination of stenotic pulmonary trunk with presence of right ventricular to coronary artery fistulous connections probably impaired myocardial perfusion after birth.

Coronary Vessel Anomalies↗
PubMed1988

Solitary arterial trunk with pulmonary atresia and arteries with supply to the left lung from both an arterial duct and systemic-pulmonary collateral arteries.

We report a case of pulmonary atresia with ventricular septal defect and absent pulmonary trunk. The sources of pulmonary blood supply were the arterial duct and systemic pulmonary collateral arteries. The left lung received blood from both sources which is very rare. One of the systemic pulmonary collateral arteries arose from the right coronary artery in an unusual fashion.

Collateral Circulation↗
PubMed1988

A histological study of the atrioventricular junction in hearts with normal and prolapsed leaflets of the mitral valve.

The mitral annulus is the point at which the atrial and ventricular walls meet the base of the mitral valve cusps. The suggestion that a variant of this arrangement termed "disjunction" was associated with prolapse of the leaflets prompted examination of the mitral atrioventricular junctions in seven normal hearts and six with prolapse owing to floppy mitral valves. A complete cord-like ring of connective tissue that encircled the atrioventricular junction and into which the three components were inserted at the same point was found in only one heart. The remaining hearts all showed a mixture of segments in which either the three components were inserted into a cord or simply met. Disjunction, defined as a separation of the atrial wall-mitral valve junction from the other component, the left ventricular wall, can occur both with and without a cord-like annulus. There was no significant difference in the number of segments around the left atrioventricular junction which showed disjunction in hearts with normal or prolapsing leaflets. The feature termed disjunction is an anatomical variation of the normal morphological characteristics of the left atrioventricular junction.

Aged↗
PubMed1988

Measurements of the dimensions of the aortic and pulmonary pathways in the human fetus: a correlative echocardiographic and morphometric study.

Thirty normal hearts from fetuses aborted at 10-33 weeks' gestation were measured directly and the results were compared with echocardiographic measurements in 20 normal live fetuses of 23-27 weeks' gestation. The diameters of the aorta, aortic isthmus, pulmonary arteries, and arterial duct were measured at standard levels and expressed as a ratio of the diameter of the ascending aorta. The ratios for the isthmus, the duct, and the right pulmonary artery were: 0.63 (0.11), 0.51 (0.13), 0.56 (0.10) respectively for the direct measurement and 0.73 (0.07), 0.7 (0.08), 0.62 (0.06) respectively at echocardiography. These results show that in mid-gestation the isthmus of the human fetus is not as small as that reported in animal models. This indicates that the distribution of the fetal circulation may not be the same either.

Aorta↗
PubMed1988

Coronary venous aneurysms and accessory atrioventricular connections.

Histological investigation of a heart with aneurysmal malformation of the anterior cardiac vein showed atypical accessory atrioventricular pathways that could have been the basis for bypass tracts and ventricular pre-excitation. Review of other cases with coronary sinus or venous aneurysms showed a striking association with sudden death. Such malformations may not be as benign as previously thought.

Coronary Aneurysm↗
PubMed1988

The arterial supply to the right atrium and the sinus node in classic tricuspid atresia.

Dissection was performed in 41 hearts from patients with classic tricuspid atresia so as to demonstrate the major arteries supplying the right atrium and the sinus node. A right anterior atrial artery was identified in 85.4% of the hearts, a right lateral atrial artery was seen in 68.3%, a right posterior atrial artery in 41.5%, and a left anterior atrial artery in 78.0% of the specimens. The artery to the sinus node, identified in 34 hearts, originated from the right coronary artery in 38% of the cases, from the left coronary artery in 59%, and had a dual origin in 3% of cases. The relative importance of these arteries is discussed with regard to the atriopulmonary anastomosis of the Fontan procedure. Special consideration is given to the incisions employed in different variations of this operation and the arterial distribution is compared to that found in the normal heart.

Coronary Vessel Anomalies↗
PubMed1987

The pathology of balloon pulmonary valvoplasty.

The pulmonary valve was examined following balloon dilation of pulmonary valve stenosis in six children. Stenosis was due to commissural fusion in two. In these patients, cineangiography showed that the valve was slightly thickened and "domed" during systole. Balloon valvoplasty produced complete separation of fused commissures in one and partial separation in the other. Commissural splitting is likely to be the most common mechanism of relief of pulmonary stenosis by balloon dilation. Incomplete separation could account for the partial reduction of the gradient in most children treated with this technique. Four children had pulmonary valve dysplasia. Balloon valvoplasty did not produce haemodynamic improvement or morphological changes that were identifiable at the time of surgical correction. Tearing of pulmonary valve tissue and avulsion of pulmonary cusps were not seen in this series.

Adolescent↗
PubMed1987

Pulmonary atresia with hypoplastic left ventricle.

We report a case with concordant atrioventricular connexion in association with pulmonary atresia and origin of the aorta from the right ventricle. The left ventricle was hypoplastic and the ventricular septum intact.

Heart Ventricles↗
PubMed1987

The ventricular septal defect in complete transposition of the great arteries: pathologic anatomy in 57 cases with emphasis on subaortic, subpulmonary, and aortic arch obstruction.

Fifty-seven heart specimens with complete transposition (concordant atrioventricular and discordant ventriculo-arterial connections) and ventricular septal defect were reviewed to establish the spectrum of morphology of the ventricular septal deficiency and to correlate the type of defect with presence of subarterial and aortic arch obstruction. The ventricular septal defect was single in 52 cases (27 perimembranous and 25 muscular) and multiple in five. A normal alignment between the outlet component and the rest of the muscular septum was present in 18 cases (10 perimembranous, five muscular, and three multiple). The defect was the consequence of septal malalignment in the other 39 specimens; 29 with rightward and 10 with leftward displacement of the outlet septum. Rightward displacement led to perimembranous defects in 16 cases and muscular defects in 12. In another instance, a perimembranous malalignment defect was associated with a muscular inlet defect. Subaortic stenosis due to either deviation of the outlet septum or prominence of the ventriculo-infundibular fold and septoparietal trabeculations was observed in 14 cases. Leftward displacement of the outlet septum was associated with one perimembranous and eight muscular defects and with multiple (muscular outlet plus muscular inlet) defects in another case. Of these, five cases showed subpulmonary stenosis. Aortic arch obstructions were present in 19 cases; 14 showed rightward malalignment of the outlet septum, which produced subaortic stenosis. These findings suggest two things: Unlike the situation in hearts with "normally related" great arteries, most defects in complete transposition result from malalignment of the outlet septum, with many being of the muscular type. Rightward or leftward displacement of the outlet septum frequently results in subaortic or subpulmonary stenosis, respectively. Aortic arch obstructions, although frequent, are not always associated with subaortic stenosis.

Adolescent↗
PubMed1987

Conjoined twins, right atrial isomerism, and sequential segmental analysis.

Three cases of twins conjoined across the chest were examined. In one set, one twin showed right atrial isomerism and the other showed the usual atrial arrangement. The other two sets showed the usual atrial arrangement in both twins. The associated cardiac anomalies were diverse, ranging from atrioventricular septal defects to absent atrioventricular connections. Sequential segmental analysis was used successfully in each case to classify the complex cardiac anomalies. The first step was the recognition of the atrial arrangement. This was easily achieved despite the complexity of the intracardiac morphology.

Female↗