Arterioventricular relations and their classification. Two specimens of arterioventricular discordance and review of published reports

Transposition physiology in the setting of concordant ventriculo-arterial connections

BACKGROUND AND AIM

To review the anatomical details, diagnostic challenges, associated cardiovascular anomalies, and techniques and outcomes of management, including re-interventions, for the rare instances of transposition physiology with concordant ventriculo-arterial connections.

METHODS

We reviewed clinical and necropsy studies on diagnosis and surgical treatment of individuals with transposition physiology and concordant ventriculo-arterial connections, analyzing also individuals with comparable flow patterns in the setting of isomerism.

RESULTS

Among reported cases, just over two-thirds were diagnosed during surgery, after initial palliation, or after necropsy. Of the patients, four-fifths presented in infancy with either cyanosis or congestive cardiac failure, with complex associated cardiac malformations. Nearly half had ventricular septal defects, and one-fifth had abnormalities of the tricuspid valve, including hypoplasia of the morphologically right ventricle. A small minority had common atrioventricular junctions We included cases reported with isomerism when the flow patterns were comparable, although the atrioventricular connections are mixed in this setting. Management mostly involved construction of intraatrial baffles, along with correction of coexisting anomalies, either together or multistaged. Overall mortality was 25%, with one-fifth of patients requiring pacemakers for surgically-induced heart block. The majority of survivors were in good functional state.

CONCLUSIONS

The flow patterns produced by discordant atrioventricular and concordant ventriculo-arterial connections remain an important, albeit rare, indication for atrial redirection or hemi-Mustard's procedure with bidirectional Glenn. The procedure recruits the morphologically left ventricle in the systemic circuit, producing good long-term functional results. The approach can also be used for those with isomeric atrial appendages and comparable hemodynamic circuits.

Anatomy of discordant atrioventricular connections

The term discordant atrioventricular connections refers to the situation in which the ventricles are connected inappropriately to the atrial chambers. In most instances, the connections of the great arteries are also abnormal, with the aorta and the pulmonary trunk arising from morphologically inappropriate ventricles. This combination results in the presence of so-called congenitally corrected transposition. Double-outlet right ventricle is occasionally present, while concordant ventriculoarterial connections may be seen rarely. Most such hearts have a range of additional abnormalities, including ventricular septal defects; outflow tract obstruction, usually of the morphologically left ventricle; anomalies of the morphologically tricuspid valve; and a highly abnormal location of the specialized atrioventricular conduction axis. Some examples exhibit bizarre abnormalities of ventricular relationships and topology, including criss-cross atrioventricular connections and superoinferior ventricular relations. In describing the anatomy of these malformations, it is important to use a step-by-step segmental approach to the documentation of the connections and associated defects in each case and to avoid potentially confusing shorthand terms.

The nomenclature, definition and classification of discordant atrioventricular connections

During the process of creation of a bidirectional crossmap between the system emerging, on the one hand, from the initiative sponsored by the Congenital Heart Committees of the European Association for Cardio-Thoracic Surgery and the Society of Thoracic Surgeons, and on the other hand, from that formulated by the Coding Committee of the European Association for Pediatric Cardiology, the Nomenclature Working Group has successfully created the International Paediatric and Congenital Cardiac Code. As would be expected, during the process of crossmapping it became clear that, for most lesions, the European Pediatric Cardiac Code was more complete in its description of the diagnoses, while the International Congenital Heart Surgery Nomenclature and Database Project was more complete in its description of the procedures. This process of crossmapping exemplifies the efforts of the Nomenclature Working Group to create a comprehensive and all-inclusive international system for the naming of paediatric and congenital cardiac disease, the International Pediatric and Congenital Cardiac Code. Although names and classification for paediatric and congenital cardiac disease will continue to evolve over time, we are now closer than ever to reaching uniform international agreement and standardization. The International Paediatric and Congenital Cardiac Code can be downloaded from the Internet, free of charge, at www.ipccc. net.

Congenital Heart Surgery Nomenclature and Database Project: corrected (discordant) transposition of the great arteries (and related malformations)

The extant nomenclature for congenitally corrected transposition of the great arteries is reviewed for the purpose of establishing a unified reporting system. The subject was debated and reviewed by members of the STS-Congenital Heart Surgery Database Committee and representatives from the European Association for Cardiothoracic Surgery. All efforts were made to include all relevant nomenclature categories using synonyms where appropriate. Congenitally corrected transposition of the great arteries is a complex cardiac lesion that is associated with ventricular septal defect, left ventricular outflow tract obstruction, and tricuspid valve abnormalities. Nomenclature for this lesion has been variable and confusing. Herein we attempt to clarify the terminology, with an emphasis on identification of synonymous and nonsynonymous appellations. A comprehensive database set is presented that is based on a hierarchical scheme. Data are entered at various levels of complexity and detail that can be determined by the clinician. These data can lay the foundation for comprehensive risk stratification analyses. A minimum database set is also presented that will allow for data sharing and would lend itself to basic interpretation of trends. Outcome tables relating diagnoses, procedures, and various risk factors are presented.

Echocardiographic and anatomic findings in atrioventricular discordance with ventriculoarterial concordance

Atrioventricular (AV) discordance with ventriculoarterial (VA) concordance is a rare form of congenital heart disease that consists of 5 different anatomic types. The salient therapeutic consideration uniting these 5 different anatomic entities is that anatomic correction can be achieved by an atrial switch procedure with closure of any associated septal defect. Three patients who had AV discordance with VA concordance are presented, with emphasis upon 2-dimensional echocardiographic diagnosis and surgical management. One of these patients had ventricular inversion with inverted normally related great arteries in situs solitus (i.e., [S,L,I]), thus representing a form of congenital heart disease that until now has not been documented anatomically. Although these are complex defects, multiple-plane imaging with 2-dimensional echocardiography was found to be extremely reliable in ascertaining the anatomy when a comprehensive, segmental analysis is applied. This approach includes determination of visceroatrial situs, ventricular loop and great arterial position and alignment. A surgical approach to closure of the ventricular septal defect through the left-sided infundibulum in isolated ventricular inversion afforded excellent exposure of the defect and avoided AV conduction block.

Ventriculoarterial discordance revisited: angiographic presentation and discussion of a typical case

This article reexamines the subject of ventriculoarterial discordance in the light of a case report and the recent literature. The angiographic method of studying complex cardiac defects is illustrated by example, in order to stress the need for a systematic, step-by-step, segmental approach to diagnosis. We favor use of the term "ventriculoarterial" discordance to refer to a defect that involves incongruence of ventricular and arterial morphologies, as predicated on the loop rule. This rule calls for anticipation of certain spatial relationships between aortic and pulmonary trunks, given certain ventricular morphologies: with a right-sided, anatomically right ventricle, for example, the ascending aorta is expected to be on the right side, whether with normally crossed or transposed great vessels (D-loop derivatives). As in the case presented here, ventriculoarterial discordance features the ascending aorta on the opposite side of the anatomically right ventricle. The influence of the formation of an abnormal cardiac apex (as in crisscrossed or superoinferior hearts) on the cardiac segments' configurations is discussed, since this too can affect the spatial relationships between the great vessels.

A case of isolated atrioventricular discordance

A case of isolated atrioventricular discordance in situs solitus is described. The importance of a well defined situs and of the presence of both ventricles in making this diagnosis is underlined and previous published reports reviewed. It is suggested that the haemodynamic concept of isolated atrioventricular discordance cannot be described only by the spatial relation between the ventricles (isolated ventricular inversion), but it should be indicted by the pattern of the connection between various flows, as shown by hearts with a normal relation between the ventricles and crossed atrioventricular connection.

Left juxtaposition of the auricles with l-position of the aorta. Report of 6 cases

Six hearts are described in which juxtaposition of the auricles to the left of the great arteries (left juxtaposition) was associated with l-postion of the aorta. Atrial anatomy was abnormal but constant; the os of the right auricle occupied the expected site of the atrial septum, producing posterior and inferior desplacement of this structure. This is of importance since the os could be mistaken for a defect of the atrial septum, while the displacement of actual defects is of significance to any intended catheterisation procedure including atrial septostomy. Five of the hearts showed atrioventricular concordance while the other specimen was an example of primitive ventricle with a right-sided outlet chamber. The ventriculoarterial connection in this latter case was normal, with l-malposition (anatomically corrected malposition). Ventriculoarterial connections in the other hearts were transposition in 3, single aortic trunk with pulmonary atresia in 1, and an intermediate between double outlet right ventricle and transposition in the other. These cases confirm the observation that juxtaposition of the auricles is associated with severe cyanotic congenital heart disease.

Successful correction of double-outlet right ventricle with a ventricular D-l-malposition of the great arteries, bilateral conus, pulmonary stenosis and subaortic ventricular septal defect

The authors present the case of a fifteen-year old girl with double outlet right ventricle with ventricular d-loop and l-malposition of the great arteries, bilateral conus, pulmonary stenosis and subaortic ventricular septal defect, who was operated on successfully. This is the fourth case of double outlet right ventricle with l-position of the aorta that has been surgically corrected. The subaortic position of the interventricular defect favours the creation of the tunnel connecting the left ventricle with the aorta without obstructing the right ventricular outflow tract. The patient was doing well 11 months postoperatively.

Anatomically corrected malposition of great arteries

Four anomalous hearts are described in which the great arteries arise in unusual fashion from their morphologically appropriate ventricles. This malformation, previously termed anatomically corrected transposition, is now termed anatomically corrected malposition. This is because, following the precedent of Van Praagh and his associates, we now reserve the term 'transposition' to describe the situation in which both great arteries arise from separate morphologically inappropriate ventricles. All the hearts examined exhibited atrioventricular concordance, I with viscero-atrial situs inversus, and 3 with situs solitus. However, there were considerable variations in ventricular morphology between the cases. Thus, 2 cases exhibited atresia of the right atrioventricular valve, and in the remaining 2 cases right and levt ventricular sinuses were both identified. Two of the cases also had pulmonary atresia, and coronary artery anomalies were present in all 4. The cases emphasize the fact that the term anatomically corrected malposition describes not a discrete anomaly but only a ventriculo-arterial relation, which is one of ventriculo-arterial concordance. Doubt has previously been cast upon the existence of this as an anatomical entity. It is concluded that the relation does indeed exist, and furthermore can coexist with all varieties of atrioventricular relations. It is suggested that the differing atrioventricular relations can be distinguished by usage of the terms 'concordant' or 'discordant' anatomically corrected malposition. Finally, it is emphasized that it is necessary to distinguish this anomaly, which in most cases presents with left-sided anterior aorta, from the left-sided anterior aorta more frequently encountered in classically corrected transposition'.