Analysis of visceral heterotaxy according to splenic status, appendage morphology, or both.
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Abnormalities, Multiple↗
Biomedical subjects
R H Anderson
Publications and source records attributed to R H Anderson.
Distribution, morphology, and neurochemistry of endocardial and epicardial nerve terminal arborizations in the human heart.
BACKGROUND: The heart contains a variety of morphologically distinct nerve terminals known to influence cardiac function. Little is known about the distribution, morphology, and neurochemistry of these terminals in the human heart. METHODS AND RESULTS: We examined the entire endocardial and epicardial surfaces of infant and adult hearts obtained postmortem and at transplantation using immunohistochemical and histochemical staining of whole-mount preparations in conjunction with confocal and fluorescence microscopy. Terminals arising from nerve fibers (diameter, 6 to 10 microns) immunoreactive for myelin basic protein were identified in the atrial endocardium, epicardium, and coronary sinus, and four types were distinguished by differences in immunostained nerve area (range, 358 to 797 microns 2) and dispersion (range, 620 to 4684 microns 2). These terminals displayed immunoreactivity for tyrosine hydroxylase, neuropeptide Y, and the general neural marker protein gene product 9.5. Acetylcholinesterase (AChE) activity was detected in < 5% of endocardial terminals and in no epicardial terminals arising from myelinated fibers. The latter were observed in close proximity to mesothelial cells, and nerve fibers supplying these terminals were found to be associated with local ganglia. A distinct population of terminals (mean stained area, 35 microns 2; 18 to 53 microns 2, 95% CI; and mean dispersion, 59 microns 2; 38 to 80 microns 2, 95% CI) was demonstrated to arise from nonmyelinated fibers (mean diameter, 2.5 microns; 2.2 to 2.8 microns, 95% CI) in the endocardial plexus of the atria and left ventricle and were predominantly AChE-positive. CONCLUSIONS: Specialized nerve terminals are distributed more widely in the human heart than has been described in experimental animals. These terminals express either AChE activity or tyrosine hydroxylase and neuropeptide Y immunoreactivity, suggesting that acetylcholine, catecholamines, and neuropeptide Y may be present in sensory and autonomic nerves in the human heart.
Acetylcholinesterase↗
Diagnosis of heterotaxy syndrome.
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Heart↗
Formation of the tricuspid valve in the human heart.
BACKGROUND: Some of the problems concerning the origin of the inlet component of the definitive right ventricle were resolved in a previous study in which we showed it to be derived exclusively from the embryonic right ventricle. Questions remain, however, concerning the relative contributions of endocardial cushion tissue and myocardium to the definitive valvar apparatus guarding the right atrioventricular orifice and the origin of the valvar leaflets. METHODS AND RESULTS: The formation of the tricuspid valve was studied by scanning electron microscopic and immunohistochemical techniques. Concurrent with the development of the right atrioventricular connection, a myocardial ridge forms at the boundary between the atrioventricular canal and the embryonic right ventricle. It grows to become a myocardial gully that funnels atrial blood beneath the lesser curvature of the initial heart tube toward the middle of the right ventricle. Fenestrations in the floor of the gully create an additional inferior opening in the funnel, transforming its initial anterior rim into the septomarginal trabeculation. The septum formed by the fusion of the endocardial ridges of the outflow tract becomes myocardialized in its inferior portion to form, in part, the outlet septum and, in part, the supraventricular crest. The smooth atrial surface of the tricuspid valvar leaflets develops from endocardial cushion tissue. The leaflets become freely movable, however, only after delamination of the tension apparatus within the myocardium. The inferior and septal leaflets derive from the gully and the ventricular septum, their delamination being a single, continuous process. The antero-superior leaflet forms by delamination from the developing supraventricular crest. CONCLUSIONS: The leaflets of the tricuspid valve develop equally from the endocardial cushion tissues and the myocardium. The myocardium contributing to the valve comes from two sources, the tricuspid gully complex and the developing supraventricular crest. These findings facilitate the understanding of several congenital malformations.
Antibodies, Monoclonal↗
What is meant by tetralogy of Fallot [S,D,I].
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Abnormalities, Multiple↗
Anatomic spectrum of abnormal ventriculoarterial connections: surgical implications.
To clarify the salient anatomic features of surgical significance, we investigated 33 specimens representing the spectrum of abnormal ventriculoarterial connections. In those with tetralogy of Fallot or double-outlet right ventricle with subaortic ventricular septal defect, the muscular outlet septum separating the subarterial outflow tracts was always inserted into (or in front of) the anterior limb of the septomarginal trabeculation (septal band). In those having double-outlet right ventricle with doubly committed ventricular septal defect, the outlet septum was lacking. When the ventricular septal defect was in subpulmonary position, with either double-outlet or discordant ventriculoarterial connections, the outlet septum was attached to the posterior limb of the septomarginal trabeculation. The outlet septum was deviated into the subpulmonary outlet in hearts with discordant ventriculoarterial connections and pulmonary stenosis. It is the interrelations between the septomarginal trabeculation, the outlet septum, and the ventriculoinfundibular fold that hold the key to the understanding of surgical anatomy and determine the optimal choice of procedure for definitive biventricular repair.
Cardiac Surgical Procedures↗
A bicuspid pulmonary valve is not a contraindication for the arterial switch operation.
There are no obvious criteria concerning the optimal repair for complete transposition with bicuspid pulmonary valve if neither the organic changes in the valve nor the pressure gradient between the left ventricle and the pulmonary trunk are severe. Instead of intraatrial switching or intraventricular rerouting in such circumstances, we have proceeded to the arterial switch procedure in 6 patients with an adequate diameter of the pulmonary valve (greater than 100% of the calculated normal aortic orifice). Postoperative catheterization (at approximately 8 months after the procedures) showed no pressure gradient between the left ventricle and the neoaorta except for a finding of 34 mm Hg difference in 1 patient who had undergone simultaneous subpulmonary myotomy. Echocardiography (7 years later in the longest follow-up) has shown no more than slight regurgitation across the bicuspid neoaortic valve, with no progressive increase of blood velocity across the valve. From these results in the middle term, we conclude that the arterial switch procedure remains an option of choice for patients with initially bicuspid pulmonary valve, providing there is no severe subpulmonary stenosis.
Aorta↗
The forgotten interleaflet triangles: a review of the surgical anatomy of the aortic valve.
Surgical descriptions of the aortic root are not always in keeping with anatomy as observed in the autopsied heart. Although all surgeons appreciate that the concept of the aortic annulus does not imply the presence of a straight ring as a hinge point, the nature of the supporting fibrous structures relative to the semilunar attachment of the leaflets has yet to be clarified. We have analyzed 50 normal aortic roots, two fetal aortic roots sectioned histologically in horizontal and sagittal planes, respectively, and two autopsied adult hearts in which prosthetic aortic valves had been inserted during life. Our results demonstrate the important interrelationships between aortic sinuses, valvar leaflets, and supporting left ventricular structures that produce the three fibrous interleaflet triangles. It is the structure and location of these triangles that is the key to the understanding of the surgical anatomy. Our results also show that the presently used definition of commissure does not reflect adequately the extent of the zones of apposition between adjacent valvar leaflets, essential for normal function when the valve is closed.
Adult↗
Coronary arterial anatomy in double-outlet right ventricle with subpulmonary VSD.
We have examined 38 hearts with a double-outlet right ventricle with a subpulmonary ventricular septal defect. We divided the hearts into three groups according to the angle between the planes formed between the outlet septum and the remainder of the muscular ventricular septum; namely, at approximately right angles (15 hearts), parallel (11 hearts), and at an acute angle (12 hearts). The coronary arterial pattern corresponding to that seen in the normal heart was present in 11 hearts (73%) of the "right angle" group, in only one heart (8%) of the "acute angle" group, and in none of the "parallel" group. In contrast, the most common pattern in the setting of complete transposition was observed in none, 8%, and 91% of each group, respectively. Other diverse patterns were recognized in the hearts in the acute angle group, and the incidence of abnormal branching was significantly higher in this than in the other groups (p < 0.01). Knowledge of these anatomic variations in the course of the coronary arteries, some of which would cause problems at either definitive repair or reoperation, are essential for those seeking to achieve optimal surgical repair.
Coronary Vessel Anomalies↗
Understanding cardiac anatomy: the prerequisite for optimal cardiac surgery.
If advances in cardiac surgery are to continue into the twenty-first century, it will be necessary to concentrate on details of matters such as the anatomy of the heart. This will be achieved best when anatomy is described as it is observed. This approach is obscured when words are used in inappropriate fashion, or else assigned a function separate from their everyday meaning. Examples of how the congenitally malformed heart and the normal heart have been described in the past are examined within the framework of using words in their vernacular meaning. Suggestions are made to improve descriptions and understanding for the 21st century. Using the example of the "univentricular heart", it is shown how conventions debarring ventricular status to discrete chambers within the ventricular mass are, of necessity, artificial. Similar examples are used to distinguish septal from parietal structures within the heart and to elucidate the structure of some congenital malformations. For values, it is shown how proper description requires assessment of these structures in their closed as well as their open positions. Understanding of cardiac anatomy, truly a prerequisite for successful cardiac surgery, will be facilitated in future if words are used in their generally accepted sense, and if artificial conventions are avoided.
Anatomy↗
Atrial appendages and venoatrial connections in hearts from patients with visceral heterotaxy.
BACKGROUND: Venoatrial connections are important when choosing surgical options for patients with visceral heterotaxy. The precise morphology of the atriums, however, is often obfuscated by the term "visceral heterotaxy." This morphologic study aims to clarify the features of significance to the cardiac surgeon. METHODS: We investigated 183 hearts from patients known from postmortem inspection to have so-called visceral heterotaxy. The connections of the systemic and pulmonary veins to the atriums, and the detailed morphology of the atriums, were examined in each case. RESULTS: Pectinate muscles extended bilaterally to the crux in 125 hearts determined to have isomeric morphologically right appendages. The other 58 hearts all exhibited bilaterally smooth-walled vestibules, and were diagnosed as having isomeric left appendages. Bilateral superior caval veins were frequent in both groups. The inferior caval vein was right- or left-sided with equal frequency in both groups, but was interrupted only in hearts with isomeric left appendages. The pulmonary veins connected in extraatrial fashion in 48% of cases with isomeric right appendages, whereas, most commonly, pulmonary veins were connected bilaterally to the atriums in those with isomeric left appendages (60%). CONCLUSIONS: Both the morphology of the atrial appendages and the venoatrial connections need to be distinguished to establish precise diagnoses in patients with so-called visceral heterotaxy ("splenic syndromes").
Abnormalities, Multiple↗
Three-dimensional echocardiography can simulate intraoperative visualization of congenitally malformed hearts.
BACKGROUND: The new technique of three-dimensional echocardiography can display the studied anatomy in any desired view plane. We sought to establish whether the reconstructions produced could provide views of the heart comparable with those obtained by the surgeon in the operating room. METHODS: Ninety-four patients, aged 1 day to 19 years (mean, 4.3 years), were examined. The ultrasound probe was placed either on the chest or subcostally and acquired 80 to 100 perpendicular parallel images of the heart with electrocardiographic and respiratory gating. Any plane, in particular oblique planes, within the data set can be analyzed. Whenever possible, the arrangement as seen by the surgeon was photographed, or heart specimens with similar intracardiac lesions were cut to simulate the view of the surgeons, to validate the echo-cardiographic reconstructions. RESULTS: Three-dimensional reconstruction of perimembranous ventricular septal defects, atrial septal defects, or anomalies of the atrioventricular valves could be displayed as viewed through an atriotomy. In similar fashion, reconstructions of muscular or doubly committed ventricular septal defects, along with obstruction of the right ventricular outflow tract, could be prepared as seen through a right ventriculotomy. Obstruction of the left ventricular outflow tract was shown as viewed through an aortotomy. Transthoracic three-dimensional echocardiography provided additional information in the prospective diagnosis of supravalvar mitral membrane, doubly committed subarterial ventricular septal defect, and subaortic stenosis caused by a restrictive ventricular septal defect in double inlet left ventricle. CONCLUSIONS: Three-dimensional echocardiography can simulate the display of the heart as seen by the surgeon in the operating room, and therefore can aid in better planning of surgical repair.
Adolescent↗
Cardiac anatomy in patients undergoing the Fontan procedure.
BACKGROUND: Controversies in nomenclature, especially of hearts with "single ventricle," have clouded discussion and understanding of the anatomy. Many patients with such malformations are submitted to the Fontan procedure as definitive surgical palliation. The spectrum of anatomy among these patients is wide and deserves analysis in an effort to provide a simple framework for description and to eliminate confusion. METHODS: We reviewed 138 successive patients undergoing the Fontan operation at one institution to demonstrate the variability in pathology. RESULTS: Only 89 patients (65%) had a univentricular type of atrioventricular connection. All but 5 patients had two ventricular chambers. Among the 49 patients with biventricular atrioventricular connections, 43 had a hypoplastic ventricle that precluded a biventricular repair. CONCLUSIONS: Full understanding of the malformations that may preclude a "biventricular" repair and hence necessitate a Fontan procedure requires knowledge of the different forms of univentricular atrioventricular connection that, although usually associated with two ventricular chambers, are seldom amenable to a "two-pump repair." Understanding of those types of "biventricular heart" that preclude a two-pump repair (eg, severe hypoplasia of the left ventricle or the right ventricle) or are associated with high risks (eg, straddling atrioventricular valve) is also important.
Fontan Procedure↗
Fibrous obstruction within the left ventricular outflow tract associated with ventricular septal defect: a pathologic study.
OBJECTIVES: We examined the nature of ridges within the left ventricular outflow tract associated with ventricular septal defects that might be found by echocardiography. BACKGROUND: Echocardiography displays even small ridges well. Surgical removal of such ridges at the time of defect closure is recommended. METHODS: We examined 37 heart specimens with ventricular septal defects with a ridge, noting its nature and relation to the defect and adjacent valves. We excluded left ventricular outflow tract obstruction associated with complex lesions. RESULTS: Defects were perimembranous in 25 specimens, muscular in 8 and part of an atrioventricular septal defect in 5. Some hearts had multiple defects. Many of the original reports had not mentioned ridges. Three distinct ridge patterns were found. The first (n = 18) was a fold of endocardial tissue related to the membranous septum. The second (n = 12) was a defect of a fibrous nature; in 8 this was a discrete, protuberant fibrous ridge, and in 4 the obstruction was diffuse, which we termed keloidal. The third pattern (n = 7) lay circumferentially around the ventricular septal defect, seemingly associated with the defect's attempted spontaneous diminution in size. Endocardial folds were not found in specimens from patients > 5 years old. Fibrous and keloidal lesions, which may represent a continuum of progression, generally were found in specimens from older patients. Histologic studies of 17 specimens confirmed the morphologic findings. The endocardial folds were endothelial tissue, whereas the fibrous and keloidal ridges were of fibrous tissue, as were circumferential lesions. All specimens had mitral-semilunar valvular continuity. CONCLUSIONS: Endocardial fold and circumferential lesions appear to be benign. The endocardial folds arose from the membranous ventricular septum, were not protuberant and usually were found in younger patients. The fibrous ridges, in contrast, were protuberant and were always associated with the underlying muscle of the outlet septum. These pathologic distinctions may facilitate echocardiographic diagnosis and prognosis.
Adolescent↗
Echocardiographic-morphologic correlations in tricuspid atresia.
OBJECTIVES: Our aim was to clarify the anatomic substrate in hearts diagnosed as having tricuspid atresia by studying autopsy specimens and comparing the findings with those in two-dimensional echocardiograms. BACKGROUND: Traditionally, tricuspid atresia was thought, and is still believed by some, to be due to an imperforate valvular membrane interposed between the floor of the blind-ending right atrium and the hypoplastic right ventricle. Others argued that the dimple, when present, pointed to the outflow tract of the left ventricle rather than to the right ventricle, making the lesion more akin to double-inlet left ventricle. METHODS: We examined 39 autopsy specimens catalogued as having tricuspid atresia. We then studied 24 two-dimensional echocardiograms from patients with a primary diagnosis of tricuspid atresia. RESULTS: Of the 39 specimens, 37 had a completely muscular floor to the right atrium (absent right atrioventricular [AV] connection). The dimple, when identified, was (except in one case) directed to the left ventricular outflow tract. Only two hearts had an imperforate tricuspid valve. Two-dimensional echocardiograms in all cases showed an echo-dense band, produced by the fibrofatty tissue of the AV groove and representing absence of the right AV connection, between the muscular floor of the morphologically right atrium and the ventricular mass. CONCLUSIONS: Tricuspid atresia is usually, but not always, due to morphologic absence of one AV connection. In most cases, the ventricular mass then comprises a dominant left ventricle together with a rudimentary and incomplete right ventricle.
Echocardiography↗
Is a cleft in the anterior leaflet of an otherwise normal mitral valve an atrioventricular canal malformation?
OBJECTIVES: This study sought to ascertain the surgical anatomy of a cleft in the left atrioventricular (AV) valve. BACKGROUND: Important morphologic differences exist between hearts with a cleft in the anterior leaflet of an otherwise normal mitral valve and those with a so-called cleft in the left AV valve when there is an AV septal defect, but it has been customary to link the lesions together on developmental grounds. METHODS: Eight autopsied specimens with a cleft in the aortic (or anterior) leaflet of the mitral valve were studied in detail, and echocardiograms from 21 patients with such a cleft were compared with the specimens and with findings typical of the so-called partial AV canal and other forms of AV septal defect. RESULTS: The structure and direction of the cleft, location of the papillary muscles within the left ventricle and AV junctional morphology of hearts with an otherwise normally structured mitral valve were significantly different from typical findings in hearts with AV septal defects. CONCLUSIONS: It is necessary to distinguish morphologically a cleft in an otherwise normally structured mitral valve in hearts with separate right and left AV junctions from the trifoliate left component of a common AV valve in hearts with an AV septal defect and a common AV junction because the disposition of the AV conduction tissues varies markedly between the lesions.
Autopsy↗
The relationship of the outlet septum to the aortic outflow tract in hearts with interruption of the aortic arch.
We examined 13 hearts with concordant atrioventricular and ventriculoarterial connections and interruption of the aortic arch to establish and describe the morphologic features of the outflow tracts in relation to axial deviation and malalignment of the outlet septum as opposed to overriding of the arterial valvular orifices. Interruption in all cases but one was between the left common carotid and left subclavian arteries; the other arch was interrupted at the isthmus. A patent arterial duct and ventricular septal defect were universally present. When its borders were viewed from the right ventricle, the ventricular septal defect was perimembranous in seven hearts, had exclusively muscular borders in four hearts, and was doubly committed and juxta-arterial in the remaining two hearts. Malalignment between the muscular ventricular septum and outlet septum, or a fibrous raphe, as judged when the heart was viewed in its short axis, was found in 12 of the hearts. Posterior and leftward axial deviation of the outlet septum in its long axis was found in 4 of the 12 hearts and also in one heart that did not have short-axis malalignment. Attachments of the leaflets of the pulmonary valve in both right and left ventricles, however, were present in only one of the specimens, this being a case with a doubly committed and juxta-arterial defect. These separate features of the outflow tract in hearts with interruption of the aortic arch, therefore, require thorough assessment when surgical management is planned. All these variable features can be assessed preoperatively by cross-sectional echocardiography, which should be directed toward defining the degree of development and alignment of the outlet septum, as well as the length of the subpulmonary infundibulum.
Aorta, Thoracic↗