Florida is the fourth largest state in the United States of America. “Heart Week in Florida” is a joint collaborative project sponsored by The Children's Hospital of Philadelphia and The Congenital Heart Institute of Florida. The cardiac programme of Children's Hospital of Philadelphia is one of the largest and most prestigious comprehensive cardiac programmes in the world. The Congenital Heart Institute of Florida is the largest programme providing services for patients with congenital cardiac disease in Florida. Both institutions are very grateful to Bob Anderson, and the team at Cardiology in the Young, for their support of “Heart Week in Florida”, and for the opportunity to publish this Supplement. Bob Anderson was a valued faculty member, and tremendous supporter, of both the fourth annual International Symposium on Congenital Heart Disease held at All Children's Hospital and University of South Florida, and the seventh annual Update on Pediatric Cardiovascular Disease organized by Children's Hospital of Philadelphia.

The normal heart possesses two ventriculo-arterial junctions – one for the aortic valve, and the other for the pulmonary valve. In the normal heart, these pulmonary and aortic roots are discrete and separate structures, the subpulmonary infundibulum being a free-standing muscular sleeve, separated by extracardiac space from the outflow tract of the left ventricle. When considering the congenital malformations that can distort these outflow tracts, it is conventional to categorise them as existing at subvalvar, valvar, and supravalvar levels. Such an approach, however, ignores the fact the valvar leaflets themselves extend through a significant length of the outflow tracts, with so-called supravalvar stenosis almost always involving the sinutubular junction, this being an integral part of the mechanism that normally ensures competent valvar closure. When considering the lesions that involve abnormally structured outflow tracts, these are best analysed by recognising the different features of the ventriculo-arterial junctions, namely the way the arterial trunks are joined to their underlying ventricles, the interrelationships of the trunks one to the other, and the arrangement of the supporting ventricular structures. In this review, we will show how knowledge of the arrangement of the normal junctions provides the necessary scaffold for logical analysis of all the lesions that can afflict the outflow tracts, be they otherwise normally or abnormally structured.

In the normal heart, the morphologically right ventricle supports the pulmonary trunk. The key to echocardiographic evaluation of the junction between these structures is to understand not only the arrangement of the pulmonary valve, but also the complete muscular infundibulum that supports the valvar leaflets, lifting the valvar complex away from the base of the ventricular mass. As explained in the previous review,1 it is the presence of this free-standing muscular infundibular sleeve that makes it possible for the surgeon to remove the pulmonary valve for use as an allograft in the Ross procedure.2 In this review, we will address the echocardiographic features of the junction, considering primarily the situation in which the morphologically right ventricle supports the pulmonary trunk, but making comparisons with the abnormal arrangements in which either the aorta, or both arterial trunks, arise from the right ventricle. As we will see, the basic arrangement of the free-standing complete muscular infundibulum, or conus, is preserved with these abnormal arrangements, but there can be variation depending on the precise arrangement of the inner heart curvature, or ventriculo-infundibular fold, and the morphology can be further changed depending on the relationship of the arterial trunks themselves. The key to analysis, therefore, and also to accurate description, is to analyse separately the way in which the arterial trunks are joined to the ventricular mass, the relationships of the trunks one to the other, and the precise structure of the supporting right ventricular outflow tract, or outflow tracts in the setting of double outlet connection. If each of these features is then described in its own right, avoiding the temptation to make inferences regarding one feature from knowledge of another, then it is possible to avoid many of the persisting controversies relating to nomenclature.

The previous reviews in this section of our Supplement1,2 have summarized the anatomic components of the ventriculo-arterial junctions, and then assessed the echocardiographic approach to the ventriculo-arterial junction or junctions as seen in the morphologically right ventricle. In this complementary review, we discuss the echocardiographic assessment of the comparable components found in the morphologically left ventricle, specifically the outflow tract and the arterial root. We will address the echocardiographic anatomy of the aortic valvar complex, and we will review the causes of congenital arterial valvar stenosis, using the aortic valve as our example. We will also review the various lesions that, in the outflow of the morphologically left ventricle, can produce subvalvar and supravalvar stenosis. We will then consider the salient features of the left ventricular outflow tract in patients with discordant ventriculo-arterial connections, and double outlet ventricles. To conclude the review, we will briefly address some rarer anomalies that involve the left ventricular outflow tract, showing how the transesophageal echocardiogram is used to assist the surgeon preparing for repair. The essence of the approach will be to consider the malformations as seen at valvar, subvalvar, or supravalvar levels,1 but we should not lose sight of the fact that aortic coarctation or interruption, hypoplasia of the left heart, and malformations of the mitral valve are all part of the spectrum of lesions associated with obstruction to the left ventricular outflow tract. These additional malformations, however, are beyond the scope of this review.

Surgical therapy for tetralogy of fallot is one of the success stories of the early era of cardiac surgery. Despite the many advances of the ensuing fifty years, such as new techniques for imaging, extension of surgical therapy to the neonatal period, and improved treatment in the intensive care unit, there has been an increasing recognition that the outcomes for many patients over the long term remain less than optimal. Mortality for surgical correction of tetralogy of Fallot, even in very small neonates, approaches zero at most institutions. Patients remain at risk, however, for right ventricular dysfunction, congestive heart failure, and an ongoing need for future therapeutic interventions, including cardiac catheterization and re-operation. Surgical reconstruction of the abnormal subpulmonary right ventricular outflow tract often results in pulmonary insufficiency and scarring, leading to ventricular volume overload and dysfunction. Postoperative right ventricular dysfunction may be associated with congestive heart failure, poor exercise tolerance, arrhythmias, and sudden death. The chapters which follow in this section of our supplement focus on the current state of knowledge concerning treatment and management of patients with pulmonary insufficiency following surgical repair of tetralogy of Fallot. There is considerable controversy concerning the clinical significance of pulmonary insufficiency; there is no standard technique for the assessment of right ventricular function; and there are considerable disagreements concerning the optimal timing of surgical re-intervention to replace the pulmonary valve. I believe that the reviews will help clarify these important issues.

It is now well over one hundred years since Arthur Louis Etienne Fallot showed that four discrete morphologic abnormalities co-existed in the majority of patients he had autopsied with “la maladie bleu”,1 or cyanosis as we now describe it. The lesions he identified were an interventricular communication, subpulmonary stenosis, biventricular origin of the aortic valve, and right ventricular hypertrophy. We now know that the combination of these anomalies had been recognised long before Fallot's epochal description. Indeed, it is Neils Stensen, the Danish monk who also described the parotid duct, who is usually acknowledged as being the first to describe the entity that we now call tetralogy of Fallot.2 Cases were certainly described by John Hunter,2 whilst with the benefit of hindsight, we can see an unequivocal example illustrated by the Baron von Rokitansky3 in his ground-breaking atlas (Fig. 1).

With advances in surgical technique, more children with complex congenital heart disease are surviving.1 Increasingly, attention is focusing on late morbidities, such as right ventricular dysfunction.2 For many common forms of congenital cardiac malformations, the assessment of right ventricular size and function is now essential so as to make optimal decisions concerning management.3 Commonly encountered examples include the timing for operative replacement of the incompetent pulmonary valve following surgical repair of tetralogy of Fallot, and the assessment of suspected ventricular dysfunction in children with functionally single or systemic right ventricles.4 Echocardiography remains the most practical method for serially determining right ventricular function, despite its limitations.5 The easy accessibility of echocardiography has encouraged its continued development as a tool for determining right ventricular function in neonates, infants, and children. A comparison of values established for the right ventricle is shown in Table 1, along with the references from which they were culled. We will describe these values in sequence.

Insufficiency of any of the four cardiac valves is a common cause of heart failure in children. Progression of ventricular dysfunction can be predictable, but requires thorough understanding of valvar disease. In valvar regurgitation, the heart has to cope with an increased volume of blood. The pathophysiological sequence is similar for both the right and the left heart. There is initially an increase in end-diastolic volume, followed by an increase in end-systolic volume, and at the end, a decrease in the shortening and ejection fractions. Different compensatory mechanisms and pathophysiologic adaptations develop to maintain the stroke volume for each type of valvar insufficiency, but heart failure eventually ensues. When symptoms of heart failure develop, irreversible ventricular dysfunction is often established, and outcome after surgery may ultimately be compromised. Discerning the optimal time for intervention, before irreversible ventricular dysfunction develops, is a key point in the management of regurgitant valvar heart disease.

After repair of tetralogy of Fallot, many patients present in need of reoperative surgical reconstruction of the right ventricular outflow tract. The predominant physiologic lesion is pulmonary insufficiency, but there may also be varying degrees of obstruction of the right ventricular outflow tract. In the past, it has been felt that patients tolerate pulmonary insufficiency reasonably well. In some patients, however, the long-term effects of pulmonary insufficiency and subsequent right ventricular dilation and dysfunction are associated with poor exercise tolerance and increased incidence of arrhythmias and sudden death.1,2 Numerous studies support replacement of the pulmonary valve as treatment for pulmonary insufficiency in order to improve performance, optimize hemodynamics, and better control arrhythmias.3–10 The indications for reconstruction of the right ventricular outflow tract in this setting, nonetheless, as well as the operative strategy, continue to evolve. There are multiple surgical options for replacement of the pulmonary valve for these patients, including aortic and pulmonary homografts, stented and stentless porcine valves, porcine valved conduits, bovine jugular venous conduits, and even mechanical valves and mechanical valved conduits.11–32 It was a less than ideal experience with these currently available options that stimulated our interest into employing alternative materials and techniques. Favorable experimental and clinical experience with valves made of a polytetrafluoroethylene monoleaflet33–36 encouraged us to consider a new method of reconstruction with this material, using a bifoliate polytetrafluoroethylene valve. In this work, we review our indications for replacement of the pulmonary valve after repair of tetralogy of Fallot, the surgical options available, and our experience reconstructing the right ventricular outflow tract with a new surgically created bifoliate polytetrafluoroethylene valve.

My role in the debate between myself and Bill Gaynor is to substantiate the notion that severe pulmonary valvar insufficiency should be treated in aggressive fashion. This gives me few problems. At Children's Memorial Hospital in Chicago, we have a long tradition of favouring early insertion of new pulmonary valves in patients with significant pulmonary valvar insufficiency following repair of tetralogy of Fallot. Our results with this strategy in the current era were first presented in 1986 at the Western Thoracic Surgical Association.1 At that time, we had inserted pulmonary valves late following repair of tetralogy of Fallot in 42 patients. We postulated that early control of pulmonary insufficiency may prevent long-term deterioration in right ventricular function. The fact that this is a controversial issue became immediately apparent during the discussion of our presentation. Dr. Frank Spencer, from New York, stated “I would completely disagree with the concept of electively inserting a porcine valve in a child on the basis of haemodynamic data. I fear that the approach recommended in this presentation is probably treating one disease by creating a worse one.”

It's always hard to follow a presentation by Carl Backer. Today, we have heard several presentations about the problem of pulmonary insufficiency. We have been shown multiple images of dilated and poorly functioning right ventricles. The obvious conclusion is that these patients should undergo replacement of the pulmonary valve. I agree with Carl that operative morbidity and mortality for replacing the pulmonary valve is minimal, but we must also consider the outcomes in the long-term. Most physicians would agree that valvar replacement is indicated in a symptomatic patient with right heart failure and exercise intolerance. In order to win this debate, therefore, it will necessary to redirect and alter the question! The question I am going to consider is: “should we replace prophylactically the pulmonary valve in asymptomatic patients with pulmonary insufficiency and right ventricular dilation?

In the past, most arguments concerning transposition devolved on how best to define it. When Mathew Baillie described the first case, at the end of the eighteenth century, he had no problems. He simply called it a singular malformation!1 Subsequent to Baillie's description, arguments raged amongst morphologists and pathologists as to whether the entity was best described on the basis of how the aorta was related to the pulmonary trunk, or according to the origin of the arterial trunks from inappropriate ventricles. There is little doubt now that all clinicians diagnose transposition on the basis of discordant origin of the arterial trunks from the ventricular mass, although there is still debate as to whether this discordant origin is best described in terms of connections2 or alignments.3 There remain some, nonetheless, who still describe entities such as “double outlet with transposition”, using this phrase to describe the arrangement in which both arterial trunks arise from the right ventricle, but with the aorta positioned anteriorly. For those adopting the concepts of connections or alignments, this combination is clearly impossible.4 Yet for those who choose to define “transposition” on the basis of the anterior location of the aorta,5 this would remain an entirely logical description. These problems of nomenclature, and many more aspects of the morphology of discordant origin of the arterial trunks from the ventricular mass, are discussed at length in the first review of this part of the supplement,6 co-authored by myself, who believes firmly in the concept of connections, and Paul Weinberg, who is equally convinced that the cardiac segments are best described in terms of alignments rather than connections. Our joint review hopefully shows that differences in nomenclature nowadays are relatively minor, and even where they exist, they do not stand in the way of reaching consensus on how best to describe the segmental combination in which the atrial chambers are joined to morphologically appropriate ventricle, but the ventricles support morphologically inappropriate arterial trunks. It is this particular morphological arrangement that, for the purposes of this section of our supplement, is described as “transposition”.

It is an easy matter, nowadays, to diagnose the clinical situation in which the blood returning to the atriums passes to the morphologically appropriate ventricle, but in which the ventricles then supply morphologically inappropriate arterial trunks. The consequence of this discordance in junctional morphology, of course, is that the circulations end-up in parallel, rather than in series, with the systemic venous return being channelled back to the body, and the pulmonary venous blood returning to the lungs (Fig. 1). In the absence of associated malformations, such as atrial or ventricular septal defects, or patency of the arterial duct, this morphological arrangement is incompatible with survival. Indeed, prior to the modern era, most infants born with this combination died in the first months of life.1,2 Therapeutic innovations, notably the introduction of balloon atrial septostomy,3 have changed all that. Now, coupled with surgical advances, initially atrial redirection,4,5 and then the arterial switch procedure,6 most neonates born with the malformation can anticipate a lengthy and good quality of life. Although there is now consensus concerning the clinical management of these segmental combinations, the best way of describing the morphological arrangement has been, and remains, fraught with difficulty.

Transposition, defined as concordant atrioventricular and discordant ventriculo-arterial connections, is a common neonatal congenital cardiac malformation.1 Repair of this lesion by means of the arterial switch in the neonatal period has progressed such that preoperative factors are playing a larger role in the postoperative outcomes.

The arterial switch operation1 has now become the surgical treatment of choice for those patients born with transposition, specifically the combination of concordant atrioventricular and discordant ventriculo-arterial connections. For those working in experienced centres, the operation is now a stable and well-controlled procedure. The gathering of the necessary experience to achieve such control proceeds through two different stages. The first is the familiarity gained during the surgical transfer of the coronary arteries in those patients with the usual anatomic pattern. The second step is gain the expertise so as to cope with the more complex arrangements, in which the major coronary arteries have not only an unusual origin from the aortic sinuses, but also an unexpected epicardial course relative to the arterial pedicle. There can still be a steep learning curve as the surgeon corrects those patients with the more complex arrangements. In this review, we discuss a simplified but uniform technique for surgical transfer that permits relocation of the coronary arteries irrespective of their sinusal origin or their epicardial course. The technique has been used for more than 15 years in Hopital Marie Lannelongue in Paris,2–5 and proved its worth during the initial experience of the Senior Author (FLG) in two new centres, namely the Universitat Krankenhaus Eppendorf, Hamburg, and the Children's Hospital, Denver.

The arterial switch operation has become the preferred surgical procedure for the management of simple and complex transposition, defined on the basis of concordant atrioventricular but discordant ventriculo-arterial connections, with excellent results over the short-term, and thus far over the long-term. When transposition is associated with a ventricular septal defect, and there is additional obstruction within the left ventricular outflow tract, the complexity of the surgical repair is increased, and the surgical options are not as attractive.

The presence of an obstructed aortic arch in patients with transposition, or the Taussig-Bing variant of double outlet right ventricle, presents a formidable surgical challenge. Over the years, there have been several controversies with respect to primary versus staged repair, the best technique for reconstruction of the aortic arch, and whether to use circulatory arrest or antegrade regional cerebral perfusion. In this review, I will address all these issues and describe my favoured surgical approach at The Montreal Children's Hospital, namely the single-stage arterial switch operation with concomitant repair of the aortic arch with a patch fashioned from a pulmonary homograft, all conducted using antegrade regional cerebral perfusion.

The arterial switch operation is now recognized as the procedure of choice for treatment of infants and children born with the combination of concordant atrioventricular and discordant ventriculo-arterial connections, usually known simply as transposition. Although the Mustard and Senning atrial switch procedures achieved widespread acceptance and success, the accumulating observations at mid- to late follow-up of, first, the increasing frequency of arrhythmias and sudden death, second, late right ventricular dysfunction and severe tricuspid regurgitation and, third, high operative mortality in such patients with ventricular septal defects, have led to the worldwide use of the arterial switch operation for both simple and complex forms of transposition.1

In this review, I will address the problem as to whether children with disease of the aortic valve should undergo repair, or be put forward for the Ross procedure. So as to put this debate in the correct framework, we need to evaluate all the options for aortic valvar disease. These include not only the Ross procedure, involving the insertion of a pulmonary autograft, and valvar repair, but also the option of replacing the valve with a biological or mechanical prosthesis.

There are now many surgical alternatives available for repairing the aortic valve, depending on whether the primary problem is one of stenosis or insufficiency. Patients with insufficiency of the common truncal valve have a unique anatomic substrate, which in some cases allows an innovative strategy of repair not available for the typical patient with a diseased aortic valve. Surgeons should be aware that there are a large number of techniques described for repair of the aortic valve. Some of these are shown in Table 1. For repair of the truncal valve, in contrast, fewer techniques have been described. As shown in Table 2, they are significantly different than those available for repair of the aortic valve.