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A LARGE MORPHOLOGICAL VARIANT TRIFURCATED SEPTAL BAND IN RIGHT VENTRICLE IN MIDDLE EAST POPULATION: A CASE REPORT

Authors:
Shweta Chaudhary at Santosh University
Shweta Chaudhary
Rishi Kumar Bharti
Rishi Kumar Bharti
Rishi Kumar Bharti
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Hemali Deshpande
Hemali Deshpande
Hemali Deshpande
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Jemds.com Case Report
J. Evolution Med. Dent. Sci./eISSN- 2278-4802, pISSN- 2278-4748/ Vol. 5/ Issue 58/ July 21, 2016 Page 4042
A LARGE MORPHOLOGICAL VARIANT TRIFURCATED SEPTAL BAND IN RIGHT VENTRICLE IN MIDDLE
EAST POPULATION: A CASE REPORT
Shweta Chaudhary1, Rishi Kumar Bharti2, Hemali Deshpande3
1Assistant Professor, Department of Anatomy, College of Medicine, King Khalid University, Kingdom of Saudi Arabia.
2Assistant Professor, Department of Community Medicine, King Khalid University, Kingdom of Saudi Arabia.
3Assistant Professor, Department of Anatomy, College of Medicine, King Khalid University, Kingdom of Saudi Arabia.
ABSTRACT
During routine cadaveric dissection, we encountered a rare morphological variant of septal band in right ventricle of a human heart
in a 50 yr. old male cadaver. The band, as seen in the interior of the right ventricle, was observed to arise from middle part of
interventricular septum and was trifurcated into three prominent muscular bands. The importance of variant septal band has been
implicated in various heart surgeries on valves or placement of grafts in correction of interventricular septal defects. Presence of right
bundle branch in them may lead to various types of arrhythmias and tachycardia. Morphological variations need to be explored in order
to further evaluate its type and extent. Incidental septomarginal trabecula have also been reported in cavity of left ventricle in past. Here,
we report a large trifurcated septal band with two limbs attached directly to right ventricular wall. Importance of their role in formation
of embolus due to stasis of blood also requires attention.
KEYWORDS
Septal Band, Septomarginal Trabecula, Interventricular Septum, Right Ventricle, Heart.
HOW TO CITE THIS ARTICLE: Chaudhary S, Bharti RK, Deshpande H. A large morphological variant trifurcated septal band in right
ventricle in middle east population: a case report. J. Evolution Med. Dent. Sci. 2016;5(58):4042-4043, DOI:
10.14260/jemds/2016/924
INTRODUCTION
The interior of the right ventricular cavity is thoroughly
trabeculated. The trabeculations being attributed to irregular
muscular ridges and protrusions, collectively called trabeculae
carneae, which are lined by endocardium. One such protrusion
is the septal band or septomarginal trabecula. It reinforces the
septal surface where at the base it divides into limbs that
embrace the septal limb of supraventricular crest. In 1837, it
was given name “moderator band” as a result of his conjecture
that it might control the capacity of the right ventricle as a sort
of governor. Towards the apex, it supports the anterior
papillary muscle of the tricuspid valve and from this point
crosses to the parietal wall of the right ventricle as the
moderator band. It was named “trabecula septomarginalis” by
Tandler. A series of septoparietal trabeculations, extend from
its anterior surface and run onto the parietal ventricular
wall.[1] Usually a single band extending from middle of septum
to the base of anterior or posterior papillary muscle has been
reported in the past. Here, we report a thick trifurcated septal
band in right ventricle of human heart.
CASE REPORT
The purpose of present commentary is to report an unusual
trifurcated muscular septal band in right ventricle of a 50 yr.
old male cadaver who died of pneumonia. The muscular band
was discovered during routine dissection; it was recognized
that an unusual muscular band was 4.8 cm in length and 1.3
cm in width. The septal band was trifurcated, so that having
stem arising from interventricular septum. The stem of
muscular septal band branched into three parts, a Medial band
Financial or Other, Competing Interest: None.
Submission 10-06-2016, Peer Review 08-07-2016,
Acceptance 13-07-2016, Published 21-07-2016.
Corresponding Author:
Dr. Shweta Chaudhary,
Abha, Saudi Arabia,
King Khalid University.
E-mail: drshwetarishi@gmail.com
DOI: 10.14260/jemds/2016/924
(MB) - 2.2 cm long and 0.5 cm wide to the base of anterior
papillary muscle, Intermediate Band (IB) - 1.3 cm long and 0.6
cm wide and Lateral band (LB) - 1.2 cm long and 0.4 cm wide.
Intermediate and lateral band were merging to anterior
ventricular wall. The transverse diameter of ventricular cavity
was 3.5 - 5 cm. The right ventricular wall was 0.7 - 1 cm in
thickness and left ventricular wall was 2 - 2.2 cm in thickness.
The interventricular septum was measured to be about 3.5 cm
thickness. Cavity was smooth to larger extent. Anterior
papillary muscle was 2.6 cm in length and was attached to the
tricuspid valve with intervening chordae tendinae. Anterior
papillary muscle was longest among the three papillary
muscles. Septal papillary muscle was attached 0.2 cm below
supraventricular crest.
Fig. 1: Showing trifurcated Septal Band- A and its three
bands namely Medial Band (MB), Intermediate Band (IB),
and Lateral Band (LB). IB and LB were attached to
anterior interventricular wall and MB was merging
with the margin of anterior papillary muscle,
B- Anterior Papillary Muscle
Jemds.com Case Report
J. Evolution Med. Dent. Sci./eISSN- 2278-4802, pISSN- 2278-4748/ Vol. 5/ Issue 58/ July 21, 2016 Page 4043
DISCUSSION
Very few studies have been done in humans to define its
morphology. Animal studies have been conducted to look at
the internal anatomy of heart. In dog heart, the major branch
of the septomarginal trabeculae system was examined and it
was approximately 1 mm in width in all dogs, irrespective of
age and tended to be flattened and ribbon-like. The other
branches differed considerably in thickness.[2]
The trabeculae carneae begin to form at a rather early
stage of prenatal development – their delicate structure can be
observed at the 4th-5th week of foetal age. Discussed papers
suggest a gradual “migration” of the muscle in the early period
of fetal life from the periseptal through central to parietal
location, which may result in development of the
septomarginal trabecula.[3] Abnormalities of septal papillary
muscle and its chordae are related to defects in fusion of
ventricular and bulbar musculature and are often associated
with malformation of the septal leaflet of the tricuspid valve.
Absence of the moderator band or of the septal papillary
muscle should be viewed as congenital cardiac defects even
though no haemodynamic abnormality is produced.[4]
Mamtha et al classified them into simple type if they are
attached from septum to the base of papillary muscle and
complex type depending in their branching pattern. They
showed in most of the cases the septomarginal trabecula
originated about upper or middle third of the ventricular wall.
The thickness varied from less than 1 mm to more than 5 mm.
Our finding showed about 50-130 mm thick septal band.
Septomarginal trabecula branching before attaching to the
base of the anterior papillary muscle was also reported by
them.[5]
Raghavendra et al showed 80% specimens with moderator
band as arising from the lower segment of crista
supraventricularis. Septoparietal trabeculations were found
extending from the anterior margin of the septomarginal
trabeculation to the parietal wall in 25% specimens. Average
length of the moderator band was reported as 13.82 cm and
average thickness being 4.46 cm, which correlates with our
finding.[6]
Bandeira et al classified the septomarginal trabecula into
eight groups. They reported two components of septomarginal
trabecula, one septal and the other septal-papillary single
(32.3%) or complex (67.7%) papillary-parietal connection
was also reported. There 8.1% heart showed prominent septal
portion with single connection to papillary muscle as in our
finding, but here two extra bands were observed reaching
separately to parietal wall.[7]
Specific types of septomarginal trabeculae have been
reported by Kosinski. Most of them originated from the upper
part of the interventricular septum, separating at an angle
increasing proportionally to the number of branches of the
crista supraventricularis as well as the number of secondary
trabecula. Single type tightly connecting with the anterior
papillary muscle was most common. Weak connection of the
anterior papillary muscle and the septomarginal trabecula was
very incidental and in such cases the muscle as a rule was
located at the anterior wall of the right ventricle.[8] Our finding
is not in accordance with them, as it was a trifurcated band
which branched before embracing anterior papillary muscle.
Due to the conduction system, fibers of right bundle
branch present within the septomarginal trabecula may
involve iatrogenic complications while repair, e.g. heart
block.[9]
Therefore, presence of such variant bands creates an
alarming signal for surgeons. Admittedly, we have not
conducted histological evaluation of septal band, so as to see
the extent of merging Purkinje fibers to the ventricular wall.
Role of the trabeculae was observed during the ablation
treatment due to ventricular tachycardia. It proves that both
in the trabeculae and papillary muscles, there may occur
arrhythmogenic foci.[10]
Knowledge of these variations are significant in heart
diseases like arrhythmias, ventricular dysfunctions, septal
defects, etc. The present anomaly should be taken care of
during valvular surgeries and repair of interventricular septal
defects, especially in upper half of septum. Their radiological
evaluation in case of severe hypertension needs concern. Their
presence could be related to developmental defects of
ventricular or bulbar musculature and may lead to failure to
compensate for the body demands. Further studies on human
heart are required so as to better define the internal anatomy
of heart to better assess its dysfunction.
ACKNOWLEDGEMENT
We are grateful to all our faculty members for their kind
support and encouragement at every step. We also thank our
college administration for incredible support and wishes.
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Ventricular False Tendons in Human Hearts, an Autopsy Study of the Incidence, Morphology, Histology and Distribution in Basrah City
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  • Dec 2019
The left ventricular false tendons (LVFTs ) are fibrous or fibromuscular bands crossing the left ventricle in human hearts ,they arise mainly from the ventricular septum to the free wall or to a papillary muscle .They are considered as normal anatomical variant with different numbers, location and type. LVFTs had been associated with many clinical studies and discussions regarding their function . Literatures were reviewed and their incidence ,morphology , histology and clinical correlation were discussed .This study was intended to evaluate the existence LVFTs in Basrah city , and to compare the findings with other data verified in literatures. A prospective autopsy study of the prevalence and morphology of LVFTs in 215 cadaveric human hearts was performed to estimate the number ,types and location .of these bands .10 out of 215 samples were undergo routine histopathological processing to obtain 4 micrometer thickness slides stained with hematoxylin and eosin and examined for histological characteristics . LVFTs of varying number, types and different attachment were recorded in 62 ( 28.8% ) of 215 adult human cadaveric hearts studied. A complete morphologic assessments were done. No significant differences was found regarding age or gender. , Majority of LVFTs are single , commonly between the ventricular septum and papillary muscle .Fibrous and fibro muscular type is predominant . In our community false tendons are frequent anatomic variants of normal human LV which may be identified at routine examination and should not be mistaken as pathologic structures such as flail chordae tendineae or thrombi, further radiological and clinical studies are suggested to ensure their role and function
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Histological and anatomical variations of septomarginal trabecula in bovine hearts
Article
  • Jan 2019
The use of hearts from different animals as models in the experimental pharmacology and surgical clinic has led, in recent years, to an increase on interest of research with this organ. The heart’s conducting system, from the septomarginal trabecula, presents several variations, which generates numerous controversies in the literature. So, the objective of the present study is to analyse the morphology of the septomarginal trabecula of bovine hearts, identifying possible macro‐ and microscopic variations. Thirty‐four bovine hearts were analysed. Each trabecula was analysed macroscopically to obtain an anatomical description and measurements of its length and thickness. For histological and morphometric analysis, the samples were fixed in Bouin’s solution and then subjected to histological processing. In all the analysed bovine hearts, the septomarginal trabecula presented itself as a smooth, tubular meaty structure of muscular consistency, with variable length and diameter. The anatomical variations observed included a trabecula with forked marginal fixation, and single septal fixation, in addition to a trabecula with extremely reduced or excessively thick caliber. The septomarginal trabecula consists of cardiac muscle fibres, connective tissue, vascular tissue and conduction myofibrils or Purkinje fibres. In the samples of smaller thicknesses, there was a predominance of connective tissue and scarce cardiac muscle tissue, whereas in the thicker samples the predominance was of cardiac striated muscle tissue. Therefore, there are significant macro‐ and microscopic differences between the bovine septomarginal trabecula concerning their diameter and constituent tissue, and that can lead to possible changes in cardiac physiology.
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Morphological classification of the septomarginal trabecula in humans
Article
Full-text available
  • Nov 2011
Although the septomarginal trabecula is a well-known anatomical structure, there continue to be different ways of studying it. In this study, we dissected the muscle bundles that form it, and this has enabled us to present a new classification based on the origin, path, and termination of these bundles. This study was conducted on 99 hearts removed from the cadavers of adult humans aged 18 to 82 years, of which 72 were male and 27 were female. The septomarginal trabecula presents two components in its composition: one septal and the other septal- papillary, i.e. extending from the septum to the anterior papillary muscle. The septal component may be visible macroscopically, forming a fleshy third-order column, or may only be visible by means of dissection. The septal-papillary component is always visible and is a fleshy column of either second-order or third- -order type. Another parameter takes into consideration the papillary-parietal connection, i.e. the junction of the septomarginal trabecula with the anterior papillary muscle, which may be single or present ramifications to the anterior wall and/or apex. Taking these criteria as references, we have classified the septomarginal trabecula into eight types.
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Surgical management of multiple ventricular septal defects: The role of the felt sandwich technique
Article
  • May 2009
Recently, the felt sandwich technique has been widely used to close muscular ventricular septal defects. We evaluated the early and midterm results of our strategy (a combination of the sandwich technique and direct closures) and assessed the role of the sandwich technique in the treatment of multiple ventricular septal defects. Twenty-nine consecutive patients underwent an operation for multiple ventricular septal defects and associated cardiac malformations. They included 17 boys and 12 girls with a median age of 6.0 months. Thirteen patients had 4 or more ventricular septal defects (Swiss cheese septum). There was no surgical or follow-up mortality, and no reoperations were required. There were no cases of heart block and no significant residual shunts in the latest follow-up study. Two patients with Swiss cheese septum had postoperative congestive heart failure. Three muscular ventricular septal defects were closed with the sandwich technique in these 2 patients, whereas 1 or fewer ventricular septal defects were closed with the sandwich technique in the other 27 patients. Seven (77.8%) of 9 patients who underwent the sandwich procedure had septal dysfunction, whereas 5 (25.0%) of the other 20 patients showed septal dysfunction (P < .05). The outcome of the surgical repair of multiple ventricular septal defects was satisfactory. Although the sandwich technique is simple and effective, the use of numerous felt patches disturbed the movement of the interventricular septum. An effort should be made to close the muscular ventricular septal defect directly to avoid postoperative cardiac dysfunction. Large apical ventricular septal defects, especially those located just underneath the moderator band, are considered suitable for the sandwich technique.
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Morphological changes in the right ventricular septomarginal travecula (false tendon) during maturation and aging in the dog heart
Article
  • Jan 1980
Right ventricular septomarginal trabeculae ('false-tendons') from puppies, young adult, and older adult dogs were examined by light and electron microscopy. The connective tissue of the trabeculae obtained from the puppies and the young adult dogs had few elastic fibres, but this component was well developed in the connective tissue of the adult dogs. The trabeculae of older dogs also showed scattered foci of extracellular fat droplets, and their junctional regions nearest to the ventricular wall were often heavily laden with fat. The Purkinje cells were uniform in each group, but differed from one group to another: in the puppies they resembled typical conducting cells, being predominantly cuboidal with few, poorly developed myofibrils, whilst in the adults the Purkinje cells resembled working myocytes, being elongated with a well developed complement of longitudinally arranged myofibrils. The cells of all age groups showed a complete absence of T-tubules, simply arranged interculated discs, and frequent dilatations of the sarcoplasmic reticulum. The cells of older dogs showed separations of the undifferentiated regions of most discs. Membrane degenerations and the presence of numerous fat droplets also were common. The fine structural cytology of Purkinje cells therefore appears to change considerable with age in the right ventricular septomarginal trabeculae ('false-tendons') of the dog heart.
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Surgical anatomy of the atrioventricular conduction bundle in anomalous muscle bundle of the right ventricle with subarterial ventricular septal defect
Article
  • Feb 1985
A stillborn baby girl was found to have an anomalous muscle bundle of the right ventricle, associated with a doubly committed subarterial ventricular septal defect. The latter was separated from the area of the atrioventricular conduction bundle by muscle. Serial histologic sectioning of the specialized atrioventricular junctional area revealed that the final bifurcation of the branching bundle came astride the septum in the inferior angle of the defect. The right bundle branch bifurcated and one of its branches continued along the anomalous muscle bundle in subendocardial position. This anatomy supports the concept that the bundle, in this heart, represented an early takeoff of the moderator band. The surgical anatomy suggests that resection of the anomalous muscle bundle and closure of the ventricular septal defect might well have produced heart block. The generally accepted rule that resection of anomalous muscle bundles in the right ventricle is surgically safe should be reconsidered.
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Formation of the Tricuspid Valve in the Human Heart
Article
  • Feb 1995
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. 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. 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.
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The crista supraventricularis in the human heart and its role in the morphogenesis of the septomarginal trabecula
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  • Feb 2007
  • ANN ANAT
The crista supraventricularis and septomarginal trabecula are common elements of the right ventricle, and determine many hemodynamic phenomena. The morphological analysis of both structures in regard to their mutual relations was the aim of this study. The study was carried out on the material of preserved human hearts--fetuses, children and adults. The size and development of the crista supraventricularis was carefully evaluated. The division of its lower part, and hence the possibilities of development of the septomarginal trabecula, was divided into five types (A, B, C, D and E). The most common was type B, containing two muscular trabeculae. The width of the crista varied 1/5-3/5 of the width of the interventricular septum. On the basis of this study, a conclusion of morphological unity of the septomarginal trabecula and crista supraventricularis was drawn.
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A morphometric study on the septomarginal trabeculae in south Indian cadavers
  • Jan 2013
  • 65-70
  • H Mamatha
  • D Shenoy
  • D' Souza
Mamatha H, Shenoy D, D'Souza AS, et al. A morphometric study on the septomarginal trabeculae in south Indian cadavers. Journal of Medical and Health Sciences 2013;2(2):65-70.
Anatomical study of the moderator band
  • Jan 2013
  • 78-81
  • A Y Raghavendra
  • Kavitha
  • A Kumar
Raghavendra AY, Kavitha, Kumar A, et al. Anatomical study of the moderator band. Nujhs 2013;3(4):78-81.