Anomalous aortic origin of the left coronary artery in a horse.
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Animals↗
Biomedical subjects
S Y Ho
Publications and source records attributed to S Y Ho.
Myoarchitecture and connective tissue in hearts with tricuspid atresia.
OBJECTIVE: To compare the atrial and ventricular myoarchitecture in the normal heart and the heart with tricuspid atresia, and to investigate changes in the three dimensional arrangement of collagen fibrils. METHODS: Blunt dissection and cell maceration with scanning electron microscopy were used to study the architecture of the atrial and ventricular musculature and the arrangement of collagen fibrils in three specimens with tricuspid atresia and six normal human hearts. RESULTS: There were significant modifications in the myoarchitecture of the right atrium and the left ventricle, both being noticeably hypertrophied. The middle layer of the ventricle in the abnormal hearts was thicker than in the normal hearts. The orientation of the superficial layer in the left ventricle in hearts with tricuspid atresia was irregular compared with the normal hearts. Scanning electron microscopy showed coarser endomysial sheaths and denser perimysial septa in hearts with tricuspid atresia than in normal hearts. CONCLUSIONS: The overall architecture of the muscle fibres and its connective tissue matrix in hearts with tricuspid atresia differed from normal, probably reflecting modelling of the myocardium that is inherent to the malformation. This is in concordance with clinical observations showing deterioration in pump function of the dominant left ventricle from very early in life.
Adult↗
Cross sectional echocardiographic assessment of the extent of the atrial septum relative to the atrioventricular junction in atrioventricular septal defect.
OBJECTIVE: To study patients with atrioventricular septal defect to determine the pathognomonic morphological features of the lesion and the relation between the septal structures and the atrioventricular junction. Setting : Tertiary level paediatric cardiology centre. METHODS: Cross sectional echocardiograms from 60 patients were reviewed using qualitative and quantitative analysis. The unifying feature was the presence of a common atrioventricular junction. The overall dimensions of the septal defect were determined and related to the plane of the common junction; the extent of both the atrial and the ventricular septal components was then measured according to the site of closure of the bridging leaflets. RESULTS: In 48 cases, the common junction was guarded by a common valvar orifice, but in 12 cases there were separate right and left valvar orifices. Irrespective of the valvar morphology, no significant difference was found between the groups in terms of the dimensions of the atrial and ventricular septal components. In all patients, the hole permitting shunting at atrial level extended below the plane of the atrioventricular junction, with a variable position of the leading edge of the atrial septum itself. CONCLUSIONS: The atrioventricular junction is a common structure irrespective of valvar morphology. In spite of the presence of unequivocal shunting at atrial level, the atrial septum is usually a well formed structure, even extending in some below the level of the common atrioventricular junction.
Adolescent↗
The feasibility of complete anatomical correction in the setting of discordant atrioventricular connections.
OBJECTIVE: To evaluate the feasibility of anatomical correction based on morphological and echocardiographic findings in patients and preserved hearts with discordant atrioventricular connections. DESIGN: A retrospective study with clinicomorphological correlations to assess potential contraindications for anatomical correction in the setting of discordant atrioventricular connections. SETTING: A tertiary referral centre for congenital heart disease. MATERIAL: 25 specimens and 53 patients unified by presence of discordant atrioventricular connections. METHODS: The potential contraindications for anatomical correction were first evaluated on the basis of morphological findings in all 25 specimens with discordant atrioventricular connections collected in the department museum, including study of the major coronary arterial patterns in 20. These contraindications were then sought in a population of 53 patients examined echocardiographically between January 1992 and October 1997. RESULTS: At least one lesion was discovered that might have contraindicated anatomical correction in 14 of the specimens and in 16 of the patients. The most common lesions that might militate against the anatomical approach were severe Ebstein's malformation or straddling and overriding of the tricuspid valve, each when combined with hypoplasia of the morphologically right ventricle. Other potential contraindications were atrioventricular septal defect with common atrioventricular junction, and obstruction of the left ventricular outlet combined with a restrictive ventricular septal defect, although these may be overcome with increasing experience and expertise. CONCLUSIONS: According to the morphological and echocardiographic findings, at least 10 hearts and 37 patients would have produced no anatomical problems for the type of surgical correction in which the morphologically left ventricle is restored its rightful role as the systemic pumping chamber.
Child, Preschool↗
Mentioning smoking as a cause of death on death certificates. Relatives can be asked in death registries about smoking habit of dead person.
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Cause of Death↗
Interrupted inferior vena cava in asplenia syndrome.
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Humans↗
Anisotropic conduction in the triangle of Koch of mammalian hearts: electrophysiologic and anatomic correlations.
OBJECTIVES: The purpose of this study was to characterize anisotropy in the triangle of Koch by relating electrophysiology with anatomy. BACKGROUND: Atrioventricular (AV) node fast and slow pathway characteristics have been suggested to be due to nonuniform anisotropy in the triangle of Koch. METHODS: During atrial pacing, we determined the electrical activity within the triangle of Koch by multichannel mapping in 11 isolated hearts from pigs and dogs. Orientation of fibers was determined in nine hearts. RESULTS: Fibers were parallel to the tricuspid valve annulus (TVA) in the posterior part of the triangle of Koch. In the midjunctional area, the direction of the fibers changed to an orientation perpendicular to the TVA. During stimulation from posterior and anterior sites, activation proceeded parallel to the TVA at a high conduction velocity (0.5 to 0.6 m/s). During stimulation from sites near the coronary sinus, a narrow zone of slow conduction occurred in the posterior part of the triangle of Koch where activation proceeded perpendicular to the fiber orientation. Above and below this zone, conduction was fast and parallel to the annulus. After premature stimulation, conduction delay in the triangle of Koch increased by 4 to 21 ms; in contrast, the AH interval increased by 80 to 210 ms. CONCLUSIONS: Data support the concept of anisotropic conduction in the triangle of Koch. Activation maps correlated well with the arrangement of superficial atrial fibers. Comparison of conduction delay in the triangle of Koch and AH delay after premature stimulation disproves that anisotropy in the superficial layers plays an important role in slow AV conduction.
Animals↗
Comparison of percutaneous ventriculostomies and intraparenchymal monitor: a retrospective evaluation of 156 patients.
Intraventricular catheters (IVC) and Intraparenchymal fiberoptic catheters (IPC) are the prevalent methods of intracranial pressure (ICP) monitoring. This study assesses the complications caused by either method. Previous studies have shown a higher complication rate with IVC. In 156 consecutive patients, with IVC (n = 104) or IPC (n = 52) insertion, the demographics, Glasgow coma score (GCS), ICP, duration of monitoring, changes in monitoring device, complications and computerized tomography findings, were recorded. The patients were categorized into severe (GCS 3-8), moderate (GCS 9-12) and mild (GCS 13-15) groups. A retrospective, comparative analysis of both techniques was conducted, using Kruskal-Wallis one way analysis of variance with chi square approximation and Mann-Whitney U tests. The use of IPC at 86.5% predominated in patients with GCS 3-8, while IVC at 81.4% and 92% prevailed in GCS groups 9-12 and 13-15, respectively (p = 0.000). 43.2% IVC were used for 10+ days and 25.9% for 1-3 days, while 80% of IPC were used for less than 6 days (p = 0.000). The complication rate for IVC and IPC was 25% vs 4.4% (p = 0.000). The infection rate was 4.4% and 0.6% (p = 0.1) while, inadvertent removal 4.4% vs 1.2% (p = 0.4), respectively. Malpositions occurred only with IVC (20.1%). All documented complications were without untoward clinical sequelae. We conclude that, IVC remains comparable to IPCs in complications.
Adolescent↗
Surgical anatomy of aorto-left ventricular tunnel.
BACKGROUND: Owing to the rarity of aorto-left ventricular tunnel, surgical experience with this condition is generally limited. The anatomic configuration remains to be clarified in the light of better understanding of the normal aortic root. METHODS: Two autopsied hearts with aorto-left ventricular tunnel were examined and compared with four normal heart specimens. The normal hearts were sectioned in a variety of planes to display the ventriculoarterial junction. RESULTS: The leaflets of the pulmonary valve in both normal and abnormal hearts have semilunar attachments to a sleeve of freestanding ventricular musculature, the infundibulum. An extensive fibrofatty tissue plane then interposes between the freestanding infundibulum and the aortic sinuses. The aorto-left ventricular tunnels in the abnormal hearts pass within this tissue plane. The aortic orifice of the tunnel is distal to the level of the sinutubular junction, whereas the ventricular orifice is located within the interleaflet triangle between the right and left aortic sinuses. CONCLUSIONS: Aorto-left ventricular tunnels bypass the normal ventriculoarterial junction but do not penetrate the septal musculature. This has implications for the fine-tuning of surgical repair.
Aorta↗
What is a ventricle?
BACKGROUND: The concept of "one and a half" ventricular repair is to use "half" a ventricle to support the pulmonary circulation. The component makeup of any ventricle needs clarification for us to understand the nature of the so-called half ventricle. METHODS: The components of normal and abnormal ventricles are reviewed. RESULTS: Normal ventricles possess an inlet, an apical trabecular component, and an outlet. This tripartite approach is also logical in the description of congenitally malformed ventricles. Rudimentary and incomplete ventricles lack one or more of its component parts, and are usually hypoplastic. The location and morphology of the rudimentary ventricles correlate with the disposition of the atrioventricular conduction system. CONCLUSIONS: Recognition of the ventricular components permits determination of ventricular morphology and guidelines for the location of the atrioventricular conduction axis.
Heart Defects, Congenital↗
Pathologic substrates for 1 1/2 ventricular repair.
BACKGROUND: The concept of "one and a half ventricular repair" relates to situations where one ventricle is capable of pumping one half of the circulation while the other ventricle is deemed inadequate and requires off-loading by means of a shunt. The inadequate ventricle is usually assigned the role of pumping the pulmonary circulation. The majority of hearts potentially amenable to this repair will have one large ventricle associated with a smaller and more-or-less rudimentary ventricle. METHODS: In this review, we focused on hearts in which the morphologically left ventricle will continue to support the systemic circulation. RESULTS: Among the hearts with univentricular atrioventricular connections, a few cases of classic tricuspid atresia and cases of double-inlet left ventricle coexisting with concordant ventriculoarterial connections would be suitable for incorporating the right ventricle into the pulmonary circulation. This procedure may be feasible in some cases of straddling and overriding tricuspid valve. Hearts with pulmonary atresia and intact ventricular septum display a wide range of sizes of the right ventricular cavity. Although biventricular repair is an option for those with good-sized cavities, patients with hypoplastic right ventricles may be candidates for one and a half ventricular repair. CONCLUSIONS: For the lesions reviewed, and many others, one and a half ventricular repair can be an option.
Heart Defects, Congenital↗
The pathology of subaortic obstruction.
BACKGROUND: In hearts having the atriums connected only to a dominant left ventricle, typified by double-inlet left ventricle but seen also in lesions such as tricuspid atresia, subaortic obstruction, when it exists, is usually found at the level of the ventricular septal defect when the aorta is supported by the rudimentary right ventricle. METHODS: Heart specimens were examined to determine the nature and position of the ventricular septal defect existing between dominant left and rudimentary right ventricles when the ventriculoarterial connections are discordant. RESULTS: Most commonly, the ventricular septal defect is positioned between the muscular apical trabecular septum and the muscular outlet septum. This type of defect is found not only in double-inlet left ventricle, but also in hearts with absence of either the right or left atrioventricular connection when the other atrium is connected to a dominant left ventricle, irrespective of the position of the rudimentary and incomplete right ventricle. Obstructive lesions within the aortic arch are commonly associated with restriction at the site of the ventricular septal defect. The atrioventricular conduction bundle takes a constant course relative to the margin of the septal defect. CONCLUSIONS: Because subaortic obstruction is almost always caused by a restrictive ventricular septal defect, relief of the obstruction can be achieved by surgical enlargement of the septal defect, bearing in mind the course of the atrioventricular conduction system.
Aorta, Thoracic↗
Which hearts are unsuitable for biventricular correction?
BACKGROUND: The surgical option of biventricular repair requires two ventricles, each fully capable of supporting the systemic or pulmonary circulation. The morphologic substrates that may preclude some hearts from biventricular repair need to be assessed. METHODS: Heart specimens were reviewed to assess the morphologic mechanisms that produce an unbalanced ventricular mass and to identify features that would, potentially, be a contraindication for biventricular repair. RESULTS: Hearts with solitary and indeterminate ventricles, and hearts with essentially solitary ventricles, often have associated abnormalities of venoatrial connections and arrangement of the atrioventricular valves. In the majority of hearts with univentricular atrioventricular connections, the rudimentary and incomplete ventricle of either right or left morphology may be too small to support either the systemic or the pulmonary circulation. Straddling with overriding of the atrioventricular valve, unbalanced atrioventricular septal defect, and gross hypoplasia of one of the ventricles in hearts with biventricular connections are other mechanisms producing ventricular imbalance, which could preclude biventricular repair. CONCLUSIONS: The morphologic mechanisms that result in ventricular imbalance are mainly related to the sizes and morphology of the ventricles, septal malalignment, valvar morphology, and component make-up of the ventricles. These features will influence decision-making in considering the option of biventricular repair.
Heart Defects, Congenital↗
Interventricular communication in complete atrioventricular septal defect.
BACKGROUND: Little attention has been paid to whether the interventricular communication in complete atrioventricular septal defect is different beneath the superior and inferior bridging leaflets, a feature of obvious surgical significance. METHODS: We searched for a defect under the bridging leaflets and examined the valve morphologies in 98 autopsied and 86 surgical patients. Of the overall specimens, 27 were associated with Fallot's tetralogy, and a further 20 had subaortic stenosis, aortic coarctation, or both. In the autopsied specimens, we also measured the degree of deficiency of the ventricular septum. RESULTS: No communication was found under the inferior bridging leaflet in 30% (29 of 98) of the specimens. All 29 hearts except two without such communications showed an undivided inferior leaflet. In contrast, all patients undergoing operation except 1 had a communication beneath both bridging leaflets (p < 0.001). The absence of a communication beneath the inferior leaflet was observed more in hearts with Fallot's tetralogy (seven of 14) or those with subaortic stenosis, aortic coarctation, or both (eight of 18) than in those without associated anomalies (14 of 66; p < 0.01). Those with a communication under the inferior leaflet showed a greater deficiency of the inlet ventricular septum than did those without it (p < 0.001). CONCLUSIONS: In a certain percentage of patients with complete atrioventricular septal defect, there will be no communication under the inferior bridging leaflet. Surgeons should be aware of this possibility, particularly when confronted with a patient with obstruction in either ventricular outlet.
Child↗
Isolated congenitally complete heart block attributable to combined nodoventricular and intraventricular discontinuity.
Intraventricular together with atrial-axis and nodoventricular discontinuity, in which various parts of the conduction system are replaced by fibrous or fatty tissue, constitute the three major pathological categories of isolated congenitally complete heart block. Intraventricular discontinuity is distinctly rare, with only two previous cases reported in the literature, one of which was associated with a familial history of heart block. The cardiac conduction systems of two cases of isolated congenitally complete heart block were serially sectioned and analyzed histopathologically. The findings were correlated with the clinical features, in particular, the family histories and maternal serum anti-Ro antibodies. Both cases, a 9-day-old neonate and an 8-year-old schoolgirl, showed a combination of nodoventricular and intraventricular discontinuity, with absence of the atrioventricular penetrating bundle, the entire right, and the proximal portion of the left bundle branch. The branching bundle was absent in the first case and replaced by fatty tissue in the second. In contrast to the commoner atrial-axis discontinuity in which the atrioventricular node itself is usually replaced by fibrous or fatty tissue with variable involvement distally, the sinus node, and in particular, the atrioventricular node were normal in both of our cases. There was no family history in either case, whereas tests for the maternal serum anti-Ro antibody were positive in the first but negative in the second case. Intraventricular discontinuity as a cause of isolated congenitally complete heart block is very rare. In our cases, it co-existed with nodoventricular discontinuity. It can be sporadic, familial, or associated with positive maternal serum anti-Ro antibodies.
Atrioventricular Node↗
Morphometric analysis of atrioventricular septal defect with common valve orifice.
OBJECTIVES: We sought to analyze morphometric features of atrioventricular septal defect (AVSD) in autopsy specimens and to consider the developmental implications of obstruction in either ventricular outflow tract. BACKGROUND: Left ventricular outlet obstruction (LVO) is more prevalent in patients with Rastelli type A morphology. When tetralogy of Fallot (ToF) complicates this malformation, there is usually a free-floating superior bridging leaflet. The reasons for these associations are uncertain. METHODS: In 133 hearts with AVSD and common atrioventricular (AV) valve orifice, we measured the degrees of horizontal and anterior deviation of the great arteries from the AV valve, the diameters of the ventricular outlets and the great arteries and the degree of deficiency of the ventricular septum. RESULTS: In Rastelli type A morphology, the great arteries were deviated more leftward than in type C morphology (p < 0.01). Type A hearts also had a relatively small aorta, with a long and narrow subaortic tract. The presence of obstruction in either ventricular outlet was associated with a more oblique arrangement of the great arteries, with the pulmonary trunk being more leftward than in hearts without LVO (p < 0.01). In combination with ToF, the aorta was dextroposed and the pulmonary trunk was located more posteriorly (p < 0.01). No heart with type A morphology showed ToF (p < 0.01). CONCLUSIONS: The geometric arrangement of the great arteries correlated significantly with obstruction in either ventricular outflow tract and with the Rastelli subtypes. Malrotation of the developing outlet septum may be an embryologic factor producing obstruction, with horizontal deviation of the outlets also influencing the morphology of the superior bridging leaflet.
Aorta↗
Clinical anatomy of the normal pulmonary root compared with that in isolated pulmonary valvular stenosis.
OBJECTIVES: This study aimed to clarify the clinical anatomy of the pulmonary root. BACKGROUND: Many descriptions of valvular anatomy have focused on the annulus, leading to varied interpretations of abnormal valves. METHODS: Twenty-two heart specimens with isolated pulmonary valvular stenosis were examined to analyze the gross structure of the pulmonary root. For comparison, we examined a normal series of a similar age range together with nine adult hearts. Serial histologic sections were prepared from five specimens. RESULTS: The normal pulmonary valve is enclosed in a proximal sleeve of free-standing right ventricular infundibulum supporting the fibroelastic walls of the pulmonary sinuses at the anatomic ventriculoarterial junction. The valvular leaflets are attached in semilunar fashion across this junction, delimiting the extent of the valvular sinuses. The stenotic valves were separated into dome-shaped valves, dysplastic valves and a third group of less typical cases. In the dome-shaped valves, which had a relatively circular origin of their leaflets, three raphes were tethered to the arterial wall at the sinutubular junction, producing a waistlike narrowing. The leaflets of the dysplastic valves were attached in a relatively normal semilunar fashion, but stenosis was caused by thickening of the leaflets at their free edges. Serial histologic sections through normal and abnormal valves failed to demonstrate any well defined fibrous "annulus" that could be of clinical relevance. CONCLUSIONS: Unlike the normal and the dysplastic valves, the dome-shaped valves have circular rather than semilunar lines of attachment of the valvular leaflets. Liberation of the fused zones of apposition of the leaflets within the dome is unlikely to restore such abnormal valves to normal structure, even if this procedure relieves the stenosis.
Cadaver↗
The diagnostic features of atrioventricular septal defect with common atrioventricular junction.
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Echocardiography, Doppler, Color↗