Publications by authors named "Robert H Anderson"

548 Publications

Defining transposition: What have we learnt?

Ann Pediatr Cardiol 2021 Jan-Mar;14(1):63-66. Epub 2020 Sep 23.

Department of Paediatric Cardiac Surgery, Birmingham Children's Hospital, Birmingham, United Kingdom.

Understanding transposition is important for all who hope to effectively treat patients with the condition. The variants of the condition are frequently debated in the literature. We describe an unusual variant of transposition, in which despite the arterial roots being supported by morphologically inappropriate ventricles, the roots themselves were normally related, with the intrapericardial arterial trunks spiraling as they extended into the mediastinum. The specimen was identified following the re-categorization of our archive, and we subsequently conducted a detailed analysis of the underlying morphology. Using the principles of sequential segmental analysis, we compared the morphology with standard examples previously described. We show how it was the recognition of such hearts that promoted that concept that the combination of connections across the atrioventricular and ventriculo-arterial junctions was the essence of transposition. In the most common variant, the arrangements are concordant at the atrioventricular junctions, but discordant at the ventriculo-arterial junctions. We suggest that the overall arrangement of discordant ventriculo-arterial connections is best described simply as "transposition." When the discordant ventriculo-arterial connections are combined with similarly discordant connections at the atrioventricular junctions, the transposition is congenitally corrected. We point out that the use of "d" and "l" as prefixes does not distinguish between transposition and its congenitally corrected variant. For those using segmental notations, the correct description for the rare variant found in the setting of a posteriorly located aortic root with the usual atrial arrangement is transposition (S, D, NR).
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http://dx.doi.org/10.4103/apc.APC_181_19DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7918027PMC
September 2020

Publishing patterns and citation performance of manuscripts relating to paediatric cardiology and congenital heart disease: comparison of paediatric and adult cardiology journals.

Cardiol Young 2021 Feb 24:1-5. Epub 2021 Feb 24.

Department of Genetics, Cardiovascular Research Centre, Institute of Genetic Medicine, Newcastle University, Newcastle Upon Tyne, UK.

Background: Manuscripts pertaining to paediatric cardiology and CHD have been published in a variety of different journals. Some of these journals are journals dedicated to paediatric cardiology, while others are focused on adult cardiology. Historically, it has been considered that manuscripts published in journals devoted to adult cardiology have greater citation potential. Our objective was to compare citation performance between manuscripts related to paediatric cardiology and CHD published in paediatric as opposed to adult cardiology journals.

Methods: We identified manuscripts related to paediatric cardiology and CHD published in five journals of interest during 2014. Of these journals, two were primarily concerned with adult cardiology, while the other three focused on paediatric cardiology. The number of citations for these identified manuscripts was gathered from Google Scholar. We compared the number of citations (median, mean, and 25th, 75th, 90th, and 95th percentiles), the potential for citation, and the h-index for the identified manuscripts.

Results: We identified a total of 828 manuscripts related to paediatric cardiology and congenital heart as published in the 5 journals during 2014. Of these, 783 (95%) were published in journals focused on paediatric cardiology, and the remaining 45 (5%) were published in journals focused on adult cardiology. The median number of citations was 41 in the manuscripts published in the journals focused on adult cardiology, as opposed to 7 in journals focused on paediatric cardiology (p < 0.001). The h-index, however, was greater for the journals dedicated to paediatric cardiology (36 versus 27).

Conclusion: Approximately one-twentieth of the work relating to paediatric cardiology and CHD is published in journals that focus predominantly on adult cardiology. The median number of citations is greater when manuscripts concerning paediatric cardiology and CHD are published in these journals focused on adult cardiology. The h-index, however, is higher when the manuscripts are published in journals dedicated to paediatric cardiology. While such publications in journals that focus on adult cardiology tend to generate a greater number of citations than those achieved for works published in specialised paediatric cardiology journals, the potential for citation is no different between the journals. Due to the drastically lower number of manuscripts published in journals dedicated to adult cardiology, however, median performance is different.
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http://dx.doi.org/10.1017/S1047951121000597DOI Listing
February 2021

Size of the shadow.

Heart 2021 Jan 28. Epub 2021 Jan 28.

Biosciences Institute, Newcastle University, Newcastle, UK.

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http://dx.doi.org/10.1136/heartjnl-2020-318810DOI Listing
January 2021

Three-dimensional visualization of the bovine cardiac conduction system and surrounding structures compared to the arrangements in the human heart.

J Anat 2021 Jan 24. Epub 2021 Jan 24.

Biosciences Institute, Newcastle University, Newcastle-upon-Tyne, UK.

In the human heart, the atrioventricular node is located toward the apex of the triangle of Koch, which is also at the apex of the inferior pyramidal space. It is adjacent to the atrioventricular portion of the membranous septum, through which it penetrates to become the atrioventricular bundle. Subsequent to its penetration, the conduction axis is located on the crest of the ventricular septum, sandwiched between the muscular septum and ventricular component of the membranous septum, where it gives rise to the ramifications of the left bundle branch. In contrast, the bovine conduction axis has a long non-branching component, which penetrates into a thick muscular atrioventricular septum having skirted the main cardiac bone and the rightward half of the non-coronary sinus of the aortic root. It commonly gives rise to both right and left bundle branches within the muscular ventricular septum. Unlike the situation in man, the left bundle branch is long and thin before it branches into its fascicles. These differences from the human heart, however, have yet to be shown in three-dimensions relative to the surrounding structures. We have now achieved this goal by injecting contrast material into the insulating sheaths that surround the conduction network, evaluating the results by subsequent computed tomography. The fibrous atrioventricular membranous septum of the human heart is replaced in the ox by the main cardiac bone and the muscular atrioventricular septum. The apex of the inferior pyramidal space, which in the bovine, as in the human, is related to the atrioventricular node, is placed inferiorly relative to the left ventricular outflow tract. The bovine atrioventricular conduction axis, therefore, originates from a node itself located inferiorly compared to the human arrangement. The axis must then skirt the non-coronary sinus of the aortic root prior to penetrating the thicker muscular ventricular septum, thus accounting for its long non-branching course. We envisage that our findings will further enhance comparative anatomical research.
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http://dx.doi.org/10.1111/joa.13397DOI Listing
January 2021

Elliot Shinebourne 18 May, 1940-29 November, 2020.

Cardiol Young 2021 Feb 25;31(2):177-178. Epub 2021 Jan 25.

King's College, London, UK.

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http://dx.doi.org/10.1017/S1047951120004801DOI Listing
February 2021

The aortic valve with four leaflets: how should we best describe this blue moon?

Eur Heart J Cardiovasc Imaging 2021 Jan 9. Epub 2021 Jan 9.

Cardiovascular Research Centre, Biosciences Institute, Newcastle University, Newcastle upon Tyne, NE17RU UK.

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http://dx.doi.org/10.1093/ehjci/jeaa420DOI Listing
January 2021

Clarification of the definition of hypoplastic left heart syndrome.

Nat Rev Cardiol 2021 Mar;18(3):147-148

Department of Paediatric Cardiac Surgery, Birmingham Women's and Children's Hospital, Birmingham, UK.

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http://dx.doi.org/10.1038/s41569-020-00500-5DOI Listing
March 2021

A Review of the Surgical Management of Aorto-ventricular Tunnels.

World J Pediatr Congenit Heart Surg 2021 Jan;12(1):103-115

Cardiothoracic Sciences Centre, 28730All India Institute of Medical Sciences, New Delhi, India.

We present a synthesis of 95 published investigations of the exceedingly rare tunnels that can exist between the aortic root and the left or right ventricles. From the 220 suitable cases included in these investigations, we reviewed the clinical presentations, modalities used for diagnosis, surgical approaches, and outcomes. Diagnostic information was provided by clinical presentation, radiographic findings, saline contrast echocardiography, computed tomographic angiocardiography, magnetic resonance imaging, cardiac catheterization, and angiocardiography. These techniques elucidated the coronary arterial origins and associated defects and defined the disease before surgery. Patients occasionally present with an asymptomatic cardiac murmur and cardiomegaly, but most suffer cardiac failure in the first year of life when the tunnel enters the left ventricle. Antenatal diagnosis by fetal echocardiography is reliable after 18 weeks of gestation. Associated defects, involving the proximal coronary arteries or the aortic or pulmonary valves, are present in nearly half the cases. Prompt diagnosis and surgical repair are important for a favorable outcome. Overall, operative mortality has been cited to be between 3% and 8.3%. Associated congenital coronary arterial anomalies, residual severe aortic stenosis, poor left ventricular function, and rupture of an infected suture line have been the reported causes of death. Despite early surgical intervention, an incidence of 16% to 60% postoperative residual aortic regurgitation of varying severity has been reported. The requirement of further repair or replacement of the aortic valve ranges from 0% to 50%. We submit that an increased appreciation of these details relative to the tunnels will contribute to improved surgical management.
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http://dx.doi.org/10.1177/2150135120954809DOI Listing
January 2021

Left Pulmonary Artery from the Ascending Aorta: A Case Report and Review of Published Cases.

J Cardiovasc Dev Dis 2020 Dec 25;8(1). Epub 2020 Dec 25.

Department of pediatrics, Newcastle University, Newcastle Upon Tyne NE17RU, UK.

The left pulmonary artery arising from the ascending aorta is an infrequent finding. It may be found isolated or with intracardiac anomalies. We present a new case of the left pulmonary artery arising from the ascending aorta and pool these findings with those of previously reported cases. Associated cardiac, extracardiac, and syndromic findings are discussed along with the implications of these in the evaluation and management of this condition.
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http://dx.doi.org/10.3390/jcdd8010001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7824649PMC
December 2020

Subepicardial and endocardial myocardial layers within the roof of the left atrium.

Heart Rhythm 2021 Mar 16;18(3):358-359. Epub 2020 Nov 16.

Biosciences Institute, Newcastle University, Newcastle-upon-Tyne, United Kingdom. Electronic address:

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http://dx.doi.org/10.1016/j.hrthm.2020.11.014DOI Listing
March 2021

Double outlet of both ventricles: morphological, echocardiographic and surgical considerations.

Eur J Cardiothorac Surg 2021 Apr;59(3):688-696

Department of Pediatric & Congenital Heart Surgery, Fortis Escorts Heart Institute, New Delhi, India.

Objectives: To describe the morphology, echocardiographic features and surgical management of the entity appropriately described as 'double outlet of both ventricles'.

Methods: Seven patients (5 males, age 0.5-7.5 months) were diagnosed to have a unique form of subarterial ventricular septal defect (VSD) and ventriculo-arterial connection, where a muscular outlet septum straddled the crest of the ventricular septum in a cruciate manner, such that both great arteries were equally committed to both ventricles. Diagnosis was established by echocardiography, with 6 patients submitted to surgical repair by means of intracardiac routing of the left ventricle to the aorta using 2 patches.

Results: Surgical repair was successful in all 6 patients in whom it was attempted. In addition, 1 patient underwent concomitant repair of aortic coarctation, and 2 had closure of multiple VSDs. We lost 1 patient to follow-up after diagnosis. Follow-up with a range from 3 months to 8 years in the remaining patients revealed all to be clinically well with satisfactory growth of both outflow tracts.

Conclusions: We describe a series of patients with the ventriculo-arterial connection best described as 'double outlet of both ventricles'. Diagnosis is readily established by echocardiography. Good early and midterm results can be expected subsequent to surgical repair using 2 patches for interventricular septation.
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http://dx.doi.org/10.1093/ejcts/ezaa378DOI Listing
April 2021

Guidelines to hypoplastic left heart syndrome.

Eur J Cardiothorac Surg 2020 Nov 9. Epub 2020 Nov 9.

Biosciences Institute, Newcastle University, London, UK.

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http://dx.doi.org/10.1093/ejcts/ezaa417DOI Listing
November 2020

How best to describe the pharyngeal arch arteries when the fifth arch does not exist?

Cardiol Young 2020 Nov 4;30(11):1708-1710. Epub 2020 Nov 4.

Department of Cardiology, All India Institute of Medical Sciences, New Delhi, India.

In the accompanying article appearing in this issue of the Journal, Prabhu and his colleagues, from Bengalaru in India, describe their experience with patients having a right aortic arch. They discuss the fact that the anomalous arrangements they encountered can all be interpreted on the basis of the hypothetical double arch proposed by Edwards. They point to the fact that interpretation of the developmental changes underscoring the production of the double arch is currently confused by reference to the so-called Rathke diagram, in which six sets of arteries are shown extending through the mesenchyme of the pharyngeal arches. As the authors point out, Graham and his associates have now shown that the alleged fifth set of pharyngeal arches do not exist. Based on our own observations, we endorse this statement. It means that new explanations must now be provided for the lesions previously described on the basis of persistence of the alleged artery of the fifth pharyngeal arch. We have previously claimed to have observed such an artery in a human fetus. We now believe, on the basis of our latest findings, that our earlier observation is better explained on the basis of presence of a collateral channel. We suggest that the so-called "fifth arch arteries" are themselves then best explained either on the basis of existence of such collateral channels, or remodelling of the aortic sac, which is the manifold, during development, that gives rise to the pharyngeal arch arteries.
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http://dx.doi.org/10.1017/S1047951120003807DOI Listing
November 2020

Morphology of vascular ring arch anomalies influences prognosis and management.

Arch Dis Child 2020 Oct 26. Epub 2020 Oct 26.

College of Medical and Dental Science, University of Birmingham, Birmingham, UK.

Objective: This study aimed to explore the anatomical features of aortic arch anomalies associated with vascular rings, hoping to identify those which may increase the risk of symptomatic presentation and surgical intervention.

Methods: This was a retrospective observational study at a single cardiac unit. Individuals diagnosed with an aortic arch anomaly, either isolated or non-isolated, between June 2014 and September 2018 were included. The morphology of the aortic arch was established via analysis of postnatal echocardiography, CT or MRI scans. CT and magnetic resonance studies were evaluated for the presence of a Kommerell diverticulum in those with aberrant vessels. Case notes were reviewed for relevant clinical data.

Results: Of those with aberrant subclavian arteries, 24/79 (30.4%) were shown to have a Kommerell diverticulum. Additional forms of congenital heart disease were present in 133/227 (58.6%) individuals. Surgical division of the vascular ring was performed in 30/227 (13.2%), most commonly in the setting of a double aortic arch (70.8%). In those with aberrant subclavian arteries, no children without a Kommerell diverticulum were referred for surgery. In those with a Kommerell diverticulum confirmed on imaging, 11/24 underwent surgery.

Conclusion: Individuals with a double aortic arch, or an aberrant subclavian artery arising from a Kommerell diverticulum, have the highest requirement for surgical intervention, especially in isolated anomalies. These individuals should remain under monitoring. The subjective nature of symptoms remains problematic. Longitudinal research is required further to understand the natural history of vascular rings and how it links to morphology.
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http://dx.doi.org/10.1136/archdischild-2020-319388DOI Listing
October 2020

Pictures are worth thousands of words.

J Card Surg 2020 Oct;35(10):2800-2801

Institute of Biological Sciences, Newcastle University, Newcastle upon Tyne, UK.

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http://dx.doi.org/10.1111/jocs.14850DOI Listing
October 2020

Identification and Morphogenesis of Vestibular Atrial Septal Defects.

J Cardiovasc Dev Dis 2020 Sep 10;7(3). Epub 2020 Sep 10.

Division of Pediatric Cardiology, University of Florida, Gainesville, FL 32611, USA.

: The vestibular atrial septal defect is an interatrial communication located in the antero-inferior portion of the atrial septum. Reflecting either inadequate muscularization of the vestibular spine and mesenchymal cap during development, or excessive apoptosis within the developing antero-inferior septal component, the vestibular defect represents an infrequently recognized true deficiency of the atrial septum. We reviewed necropsy specimens from three separate archives to establish the frequency of such vestibular defects and their associated cardiac findings, providing additional analysis from developing mouse hearts to illustrate their potential morphogenesis. : We analyzed the hearts in the Farouk S. Idriss Cardiac Registry at Ann and Robert H. Lurie Children's Hospital in Chicago, IL, the Van Mierop Archive at the University of Florida in Gainesville, Florida, and the archive at Johns Hopkins All Children's Heart Institute in St. Petersburg, Florida, identifying all those exhibiting a vestibular atrial septal defect, along with the associated intracardiac malformations. We then assessed potential mechanisms for the existence of such defects, based on the assessment of 450 datasets of developing mouse hearts prepared using the technique of episcopic microscopy. : We analyzed a total of 2100 specimens. Of these, 68 (3%) were found to have a vestibular atrial septal defect. Comparable defects were identified in 10 developing mouse embryos sacrificed at embryonic data 15.5, by which stage the antero-inferior component of the atrial septum is usually normally formed. : The vestibular defect is a true septal defect located in the muscular antero-inferior rim of the oval fossa. Our retrospective review of autopsied hearts suggests that the defect may be more common than previously thought. Increased awareness of the location of the defect should optimize its future clinical identification. We suggest that the defect exists because of failure, during embryonic development, of union of the components that bind the leading edge of the primary atrial septum to the atrioventricular junctions, either because of inadequate muscularisation or excessive apoptosis.
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http://dx.doi.org/10.3390/jcdd7030035DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7570000PMC
September 2020

Systolic excursion of the leaflets of the truncal valve: An unusual mechanism for pulmonary stenosis in common arterial trunk.

Ann Pediatr Cardiol 2020 Jul-Sep;13(3):194-198. Epub 2020 Jun 29.

Institute of Genetic Medicine, University of Newcastle, Newcastle upon Tyne, UK.

Background: Pulmonary stenosis in patients with common arterial trunk protects the pulmonary vasculature. In our recently published prospective study of common arterial trunk, some patients with sinusal origin of the pulmonary arterial segment had pulmonary stenosis induced by systolic excursion of a truncal valvar leaflet. We aimed to determine the detailed morphologic characteristics of this unusual finding.

Methods And Results: All 70 patients underwent echocardiography and computed tomographic angiography as per predefined study protocol. In selected cases, we also performed cardiac catheterization. Among 27 patients with aortic dominance, we found sinusal origin of the pulmonary arterial segment. In 5 of these patients, pulmonary stenosis was induced by systolic excursion of a truncal valvar leaflet. In all these patients, the truncal valve was trisinusate, albeit with asymmetric sinuses. The pulmonary arterial segment arose from the largest left sinus with its relatively large leaflet obstructing the pulmonary orifice during systole. In the remaining 22 patients, without pulmonary stenosis but with sinusal origin of pulmonary arterial segment, the truncal valve was quadrisinusate in 7, bisinusate in 2, and trisinusate in 13. None of the patients with quadrisinusate and bisinusate truncal valves had pulmonary stenosis. Among the 13 patients with trisinusate valves, the sinuses of the truncal valve were symmetrical in 6, while in 7, the pulmonary orifice originated from a smaller asymmetric sinus.

Conclusion: Pulmonary stenosis, produced by a relatively large leaflet of an asymmetric truncal sinus, may prevent early development of pulmonary vascular disease. Timely recognition of this unusual mechanism of pulmonary stenosis is important for optimal management.
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http://dx.doi.org/10.4103/apc.APC_22_20DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7437627PMC
June 2020

Printing of Three-Dimensional Heart Models-Is It Worth the Expense?

CJC Open 2020 Jul 31;2(4):192-194. Epub 2020 Mar 31.

Department of Cardiology, All India Institute of Medical Sciences, New Delhi, India.

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http://dx.doi.org/10.1016/j.cjco.2020.03.011DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7365816PMC
July 2020

A Review of the Surgical Management of Anomalous Connection of the Right Superior Caval Vein to the Morphologically Left Atrium and Biatrial Drainage of Right Superior Caval Vein.

World J Pediatr Congenit Heart Surg 2020 07;11(4):466-484

Department of Cardiothoracic and Vascular Surgery, All India Institute of Medical Sciences, New Delhi, India.

The present perspective is a synthesis of published investigations in the setting of anomalous connection of the right superior caval vein to the morphologically left atrium or biatrial drainage of the right caval vein. We identified 57 suitable cases from 97 investigations, reviewing the clinical presentation, diagnostic modalities utilized, surgical techniques used, and their outcomes. Clinical presentation, radiographic findings, saline contrast echocardiography, computed tomographic angiocardiography, radionuclide perfusion scan, magnetic resonance imaging, and angiocardiography provided the diagnostic information and were used to define the disease entities before surgery. We have also addressed several issues concerning the influence of the so-called heterotaxy: the establishment of the diagnosis, the variation in clinical presentation, and subsequent management. For the overall group of patients undergoing either surgical intervention or transcatheter treatment with an Amplatzer vascular plug, the operative mortality remains high at 9.5%. We submit that an increased appreciation of these disease entities will contribute to improved future surgical management.
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http://dx.doi.org/10.1177/2150135120912677DOI Listing
July 2020

Reassessment of the Location of the Conduction System in Atrioventricular Septal Defect Using Phase-Contrast Computed Tomography.

Semin Thorac Cardiovasc Surg 2020 Winter;32(4):960-968. Epub 2020 May 23.

Division of Biomedical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom.

The location of the atrioventricular conduction axis in the setting of atrioventricular septal defect has previously been shown by histology and intraoperative recordings. We have now reassessed the arrangement using phase-contrast computed tomography, aiming to provide precise measurements so as to optimize future surgical repairs. We used the system based on an X-ray Talbot grating interferometer using the beamline BL20B2 in a SPring-8 synchrotron radiation facility available in Japan. We analyzed 18 specimens. The atrioventricular node was found within a nodal triangle 1.7 mm from the coronary sinus, with 95% confidence intervals from 1.45 to 2.0 millimeters. The depth of the node from the right atrial endocardium was 1.0 mm, with 95% confidence intervals from 0.73 to 1.34 mm. The overall length of the scooped-out ventricular septum was 30.8 mm, with 95% confidence intervals from 27.5 to 34.1 millimeters. The length from the inferior atrioventricular junction to the take-off of the right bundle branch was 12.8 mm, with 95% confidence intervals from 11.12 to 14.38 mm, giving a ratio of 0.43 for the extent of the axis along the inferior septum, with 95% confidence intervals of 0.38-0.48. The length of the non-branching bundle was 6.6 mm, with 95% confidence intervals from 5.57 to 7.7 mm. The proportion of septum occupied by the non-branching bundle was 0.22, with 95% confidence intervals from 0.18 to 0.26. Our findings confirm previous histological studies, extending them by providing precise measurements to guide placement of sutures during surgical repair.
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http://dx.doi.org/10.1053/j.semtcvs.2020.03.011DOI Listing
May 2020

Anatomical Studies of Transposition - An Argument for a Unifying Morphological Classification.

Semin Thorac Cardiovasc Surg 2020 Winter;32(4):920-926. Epub 2020 May 23.

Department of Paediatric Cardiac Surgery, Birmingham Children's Hospital, Birmingham, United Kingdom; Institute of Clinical Sciences, University of Birmingham, Birmingham, United Kingdom.

In the setting of transposition, recognition of the variability in the morphology of the outflow tracts and the arterial trunks is essential for surgical repair. Presence of a unifying system for classification would minimize the risk of misunderstanding. We examined an archive of 142 unrepaired hearts with transposition, defined as the combination of concordant atrioventricular and discordant ventriculoarterial connections, combined with the clinical records of 727 patients undergoing the arterial switch procedures. In the setting of usual atrial arrangement, we found the aortic root in leftward or posterior location in up to 5% of our cohorts, making the common term "d-transposition" ambiguous. Variability in the relationship of the trunks was commoner in the setting of deficient ventricular septation, especially when the trunks were side-by-side (14% vs 5.5% when the ventricular septum was intact). Bilateral infundibulums were present in 14% of cases, and bilaterally deficient infundibulums in 3.5%. Both of these findings were more common with deficient ventricular septation. Fibrous continuity between the tricuspid and pulmonary valves was not always seen with perimembranous defects, particularly when there were bilateral infundibulums. Fibrous continuity between the leaflets of the tricuspid and mitral valves, in contrast, proved a unifying characteristic of the perimembranous defect. The combination of concordant atrioventricular and discordant ventriculoarterial connections is best described simply as "transposition," with precision provided when details are given of atrial arrangement and the relationships of the arterial trunks.
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http://dx.doi.org/10.1053/j.semtcvs.2020.05.016DOI Listing
May 2020

Variable Arrangement of the Atrioventricular Conduction Axis Within the Triangle of Koch: Implications for Permanent His Bundle Pacing.

JACC Clin Electrophysiol 2020 04 26;6(4):362-377. Epub 2020 Feb 26.

Departamento de Anatomía Humana y Biología Celular, Facultad de Medicina, Universidad de Extremadura, Badajoz, Spain.

Objectives: This study sought to describe, in detail, the angiographic, gross macroscopy, and histological dissection of the conduction axis in humans.

Background: The recent upsurge of interest in specific pacing of the atrioventricular conduction axis has emphasized the need for precise knowledge of the location of the atrial and penetrating components of the atrioventricular conduction axis.

Methods: A total of 41 human hearts were studied by serial histological sectioning and an additional 3 hearts by gross dissection. One of the hearts studied histologically was also dissected to show the location of the conduction axis prior to serial sectioning. The anatomical findings were then compared with the results of angiography undertaken in the catheter laboratory in 60 patients undergoing electrophysiological studies.

Results: Marked variation of the location of the transition from atrioventricular conduction axis to the penetrating atrioventricular bundle, or the bundle of His, relative to the landmarks of the triangle of Koch was observed. In just over one-half of both the specimens and the patients, the site of penetration was on the atrial aspect of the hinge of the septal leaflet of the tricuspid valve, with further variation noted relative to the apex of the triangle of Koch. Based on measurements of the histological sections, marked variation in the dimensions of the axis and its adjacency to the right-sided endocardium were also found. In almost three-fifths of hearts, an interventricular component of the fibrous membranous septum was not able to be identified. The significance of these findings to those who seek to perform selective pacing of the atrioventricular conduction axis are discussed.

Conclusions: Marked variability of the location of the conduction axis within the triangle of Koch is reported. In three-fifths of hearts, the interventricular component of the fibrous membranous septum is nonexistent.
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http://dx.doi.org/10.1016/j.jacep.2019.12.004DOI Listing
April 2020

Borders as opposed to so-called geography: which should be used to classify isolated ventricular septal defects?

Eur J Cardiothorac Surg 2020 10;58(4):801-808

Department of Paediatric Cardiac Surgery, Birmingham Women's and Children's Hospital, Birmingham, UK.

Objectives: Ventricular septal defects can be classified according to their borders or according to the fashion in which they open to the right ventricle, so-called geography. As yet, there is no consensus as to how they should be classified. In an attempt to achieve agreement, the International Society for Nomenclature of Congenital and Paediatric Heart Disease, in 2018, proposed a system incorporating both approaches. We have assessed the subjectivity of their suggested terms hoping to determine their suitability in the desired universal system for classification.

Methods: We examined 212 specimens held in the archive of Birmingham Women's and Children's Hospital. Each defect was described by 3 independent examiners on the basis of borders and their relationship to the landmarks of the right ventricle. The interobserver agreement was then calculated using Fleiss' method.

Results: Calculations to assess interobserver agreement showed that the examiners were more likely to agree on the borders of the defects than their so-called geography (κ = 0.804 vs κ = 0.518). The landmarks of the right ventricle proved to be highly variable such that the application of 'geographic' terms to hearts with perimembranous defects proved particularly challenging.

Conclusions: Interobserver agreement is lower when using terms based on 'geography' as opposed to borders. Whilst providing important morphological detail, the terms based on right ventricular landmarks are highly subjective. They should not be prioritized in a universal system of classification. Instead, the defects can be classified simply by using 'perimembranous', 'muscular', or 'doubly committed and juxta-arterial' as first-order terms.
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http://dx.doi.org/10.1093/ejcts/ezaa081DOI Listing
October 2020

Re-evaluation of the structure of the atrioventricular node and its connections with the atrium.

Europace 2020 05;22(5):821-830

Arrhythmia and Electrophysiology Department, Biocor Institute, Nova Lima, Brazil.

Aims: The anatomic substrates for atrioventricular nodal re-entry remain enigmatic, but require knowledge of the normal arrangement of the inputs and exist from the atrioventricular node. This knowledge is crucial to understand the phenomenon of atrioventricular nodal re-entry.

Methods And Results: We studied 20 human hearts with serial sections covering the entirety of the triangle of Koch and the cavotricuspid isthmus. We determined the location of the atrioventricular conduction axis and the connections between the specialized cardiomyocytes of the conduction axis and the adjacent working atrial myocardium. The atrioventricular node was found at the apex of the triangle of Koch, with entry of the conduction axis to the central fibrous body providing the criterion for distinction of the bundle of His. We found marked variation in the inferior extensions of the node, the shape of the node, the presence or absence of a connecting bridge within the myocardium of the cavotricuspid isthmus, the connections between the compact node and the myocardium of the atrial septum, the presence of transitional cardiomyocytes, and the 'last' connection between the working atrial myocardium and the conduction axis before it became the bundle of His.

Conclusion: The observed variations of the inferior extensions, combined with the arrangement of the 'last' connections between the atrial myocardium and the conduction axis prior to its insulation as the bundle of His, provide compelling evidence to support the concept for atrioventricular nodal re-entry as advanced by Katritsis and Becker.
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http://dx.doi.org/10.1093/europace/euaa031DOI Listing
May 2020

Three-dimensional volumetric measurement of the aortic root compared to standard two-dimensional measurements using cardiac computed tomography.

Clin Anat 2021 Apr 5;34(3):333-341. Epub 2020 May 5.

Heart Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA.

Introduction: Two-dimensional measurements are self-evidently limited when seeking accurately to represent the three-dimensional complexity of the aortic root. Volumetric measurement, therefore, seems an ideal alternative for a more accurate assessment.

Materials And Methods: We retrospectively analyzed 123 individuals undergoing cardiac computed tomography. We measured the dimensions of the sinuses of Valsalva using routine multiplanar short axis imaging. Three conventional two-dimensional methods were applied to measure the dimensions of the sinuses. These involved bisecting center of sinus-to-center of interleaflet triangle measures, along with center of sinus-to-center of sinus, and largest sinus-to-sinus measurements. We then quantified the volumes of the root using the volume-rendering method.

Results: The mean dimensions of the sinuses were significantly greater when measured using the largest sinus-to-sinus method as opposed to center of sinus-to-center of interleaflet triangle and center of sinus-to-center of sinus methods (33.6 ± 3.6 mm vs. 31.1 ± 3.1 mm and 30.9 ± 3.3 mm, p < .0001). The mean root volume of 13.6 ± 4.2 ml showed the strongest correlation with the mean dimensions of the sinuses of Valsalva measured using the bisecting method (R = .8401, p < .0001).

Conclusions: By using two- and three-dimensional measurements, we have provided average data for the structurally normal aortic root. The differences and correlations encountered should be noted when evaluating and following changes in the diseased root.
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http://dx.doi.org/10.1002/ca.23597DOI Listing
April 2021

The membranous septum revisited: A glimpse of our anatomical past.

Clin Anat 2021 Mar 25;34(2):178-186. Epub 2020 Apr 25.

Institute of Genetic Medicine, Newcastle University, Newcastle-upon-Tyne, UK.

The so-called membranous septum is the fibrous component of the septal structures within the heart. It is relatively subtle in its appearance, but of considerable significance to the understanding of cardiac function and cardiac disease, both congenital and acquired. Surprisingly, its existence was seemingly unknown until the early decades of the 19th century. At this time, those writing in the English language described it as the "undefended space," recognizing its importance in the setting of its aneurysmal dilation, and as the site of septal defects. By the initial decade of the 20th century, it had come to be recognized as the landmark to the site of atrioventricular bundle. Over the first decade of the 21st century, its clinical significance has been emphasized in the context of transcutaneous replacement of the aortic valve. In this review, we describe our own recent investigations of this fibrous part of the septal structures. At the same time, we provide a glimpse of our anatomic past, explaining how its initial description relied on the observations of young physicians taking their first steps in the investigation of cardiac anatomy.
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http://dx.doi.org/10.1002/ca.23599DOI Listing
March 2021

Fifth arch arteries: Why do developmental biologists encounter them so infrequently?

Pediatr Int 2020 Mar;62(3):421

Institute of Genetic Medicine, University of Newcastle, Newcastle upon Tyne, UK.

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http://dx.doi.org/10.1111/ped.14129DOI Listing
March 2020

Visualization and quantification of the atrioventricular conduction axis in hearts with ventricular septal defect using phase contrast computed tomography.

J Thorac Cardiovasc Surg 2020 Aug 19;160(2):490-496. Epub 2020 Feb 19.

Division of Biomedical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom.

Objective: To visualize and quantify the atrioventricular conduction axis in the setting of ventricular septal defect using phase contrast computed tomography.

Methods: We used the SPring-8 synchrotron radiation facility in Hyogo prefecture in Japan, processing and reconstructing the data with 3-dimensional software.

Results: We studied 8 hearts obtained from patients known to have had ventricular septal defects, aged from 6 to 150 days, with a median of 24.5 days. None of the individuals, however, had undergone corrective surgery. The penetrating bundle was found at a median of 1.43 mm from the septal crest, with a range of 0.99 to 1.54 mm. The distance to the nonbranching bundle to the right ventricular endocardium was 1.10 mm, with a range from 0.49 to 2.49 mm, to the origin of the left bundle branch was 2.46 mm, with a range from 1.7 to 3.18 mm, and to the origin of the right bundle branch was 2.34 mm, with a range from 0.50 to 2.59 mm. The median distance from the edge of the caudal limb of the septomarginal trabeculation to the right bundle branch was 1.04 mm, with a range from 0.81 to 1.16 mm.

Conclusions: We were able to show the precise location of the axis, with our findings suggesting that longitudinal sutures placed along the posteroinferior rim should be effective in avoiding iatrogenic injury, but sutures should not be placed in the valley between the limbs of the septomarginal trabeculation.
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http://dx.doi.org/10.1016/j.jtcvs.2020.02.036DOI Listing
August 2020

Histological examination of the potential arrhythmic substrates in the setting of Ebstein's malformation.

J Anat 2020 07 2;237(1):155-165. Epub 2020 Mar 2.

Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK.

Cardiac arrhythmias, notably Wolff-Parkinson-White syndrome, are known to represent a major issue in patients with Ebstein's malformation of the tricuspid valve. Abnormal conducting circuits, however, can also be produced by pathways extending either from the atrioventricular node or the ventricular components of the atrioventricular conduction axis, direct to the crest of the muscular ventricular septum. We hoped to provide further information on the potential presence of such pathways by investigations of six autopsied examples of Ebstein's malformation. All were studied by histological sectioning on the full extent of the atrioventricular conduction axis, with limited sectioning of the right atrioventricular junction supporting the inferior and antero-superior leaflets of the deformed tricuspid valve. We used the criteria established by Aschoff (Verhandlungen der Deutschen Gesellschaft für Pathologie, 14, 1910, 3) and Mönckeberg (Verhandlungen der Deutschen Gesellschaft für Pathologie, 14, 1910, 64) over a century ago to define abnormal connections across the atrioventricular junctions, as these definitions retain their validity for the identification of gross myocardial connections across the insulating tissues of the atrioventricular junctions. In one specimen, we found two discrete accessory myocardial connections across the parietal right atrioventricular junction. In all of the hearts, we found so-called nodoventricular connections, and in one heart we also observed a well-formed connection originating from the penetrating atrioventricular bundle. In addition to accessory myocardial connections across the parietal right atrioventricular junction, therefore, our histological findings demonstrate a potential role for direct connections between the atrioventricular conduction axis and the ventricular myocardium in the setting of Ebstein's malformation.
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http://dx.doi.org/10.1111/joa.13179DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7309280PMC
July 2020

Pathologic Characteristics of 119 Archived Specimens Showing the Phenotypic Features of Hypoplastic Left Heart Syndrome.

Semin Thorac Cardiovasc Surg 2020 Winter;32(4):895-903. Epub 2020 Feb 22.

Congenital Heart Center, University of Florida, Gainesville, Florida.

To assess the phenotypic variations found among hearts diagnosed at autopsy with hypoplastic left heart syndrome, with attention to implications related to this syndrome as an acquired disease of fetal life, rather than being the consequence of abnormal embryogenesis. We assessed 119 specimens, from 2 archives, diagnosed initially as representing hypoplastic left heart syndrome. Among the 119 specimens, the majority of which had been entered into the archives prior to the availability of surgical treatment for the syndrome, 36 (30%) had the combination of mitral and aortic atresia, 26 (22%) had mitral and aortic stenosis, and 57 (48%) had mitral stenosis combined with aortic atresia. Of the hearts with combined atresia, 92% (33 specimens) had slit-like left ventricles, compared to 12% (3 specimens) of hearts with stenosis of both aortic and mitral valves, and 2 hearts (4%) with mitral stenosis and aortic atresia (P < 0.001). Hypoplasia of the left atrial appendage was present in half (18 specimens, 51%) of those with combined atresia, as opposed to just 18% (10 specimens) of mitral stenosis combined with aortic atresia (P = 0.001). Small left ventricles with valves deemed proportional in size were found in 11 (42%) of those with combined mitral and aortic stenosis. Fibroelastosis was significantly more common in the hearts with mitral stenosis compared to those with mitral atresia (76% vs 11%, P < 0.001). The ascending aorta was significantly smaller in the hearts with aortic atresia. The variability in the morphologic findings support the notion that the lesions seen represent acquired disease occurring subsequent to closure of the embryonic interventricular communication, rather than representing abnormal embryogenesis.
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http://dx.doi.org/10.1053/j.semtcvs.2020.02.019DOI Listing
February 2020