Double outlet right ventricle

Definition

Double outlet right ventricle (DORV) is a congenital cardiac malformation in which both great arteries arise entirely or predominantly from the morphologic right ventricle.

DORV describes a type of ventriculoarterial connection (see “ Ventriculoarterial Connections ” under Anatomic Considerations in Congenital Heart Disease in Chapter 26 ).

In this chapter, DORV with concordant atrioventricular (AV) connection is discussed in detail. DORV also occurs in other settings ( Fig. 45.1 ), but when the AV connection is discordant, that becomes the surgically more important feature. Patients with this combination ( discordant atrioventricular (AV) connections and DORV ) are better considered along with others with AV discordant connection (see Chapter 47 ). DORV may also occur in patients with univentricular AV connections (see “ Ventriculoarterial Connections ” under Morphology in Chapter 52 ). It is a frequent occurrence in patients with heterotaxy (see Chapter 53 ).

An illustration shows four schematic heart models representing a double outlet right ventricle with usual great artery positions, arranged under situs solitus and situs inversus. The illustration presents four schematic heart models showing the basic configurations of double outlet right ventricle with the aorta positioned lateral to the pulmonary trunk. Each model is drawn as a square containing labeled cardiac chambers, including the right atrium R A, right ventricle R V, left atrium L A, and left ventricle L V, with circular positional markers shown above each model. Model 1 and model 2 are grouped under situs solitus. In model 1, the chamber arrangement shows R V above R A on the left side and L V above L A on the right side, with external positional markers labeled D, D, and S. In model 2, the chamber arrangement shows L V above R A on the left side and R V above L A on the right side, with external positional markers labeled L, L, and S, indicating atrioventricular discordant connection. Model 3 and model 4 are grouped under situs inversus. In model 3, the chamber arrangement shows R V above L A on the left side and L V above R A on the right side, with external positional markers labeled D, D, and I, also indicating atrioventricular discordant connection. In model 4, the chamber arrangement shows L V above L A on the left side and R V above R A on the right side, with external positional markers labeled L, L, and I. — • Figure 45.1

Traditionally the diagnosis of DORV has been based on three anatomic characteristics:

•
The degree of great vessel override over the right ventricle (RV)
•
The presence of bilateral infundibula
•
The presence of aortic-mitral discontinuity

These criteria have been controversial and no longer apply as prerequisites. Most proponents have invoked the 50% override rule, although a minority have been proponents of the 90% rule. ^,

Even then, it may be difficult to distinguish between a 40% versus a 60% override. The differentiation between Tetralogy of Fallot and DORV with subaortic ventricular septal defect (VSD) and pulmonary outflow tract obstruction may not be obvious. Recently, Ebadi and colleagues clearly demonstrated that in a morphologic study of DORV in 80 specimens, most hearts had fibrous continuity between an arterial valve and an AV valve and that bilateral infundibula were present in only 23% of cases.

One or both great arteries may directly overlie the VSD and thus arise biventricularly. For purposes of categorization, the great artery so arising is assigned to the ventricle it overlies by more than 50% on morphologic examination. Thus, when one great artery arises wholly or nearly so from the and the other great artery arises more than 50% from the RV, the condition is termed DORV. Uncommonly, both great arteries arise biventricularly in association with a doubly committed juxtaarterial VSD (see Chapter 33 , Figs. 33.8 and 33.9 ). One option is to arbitrarily assign each great artery to the ventricle above from which more than 50% arises and categorize the anomaly accordingly; the alternative is to term the malformation double outlet both ventricles.

Tetralogy of Fallot is an entity characterized by a variable amount of dextroposition of the aorta. When the aorta arises more than 50% from the RV, the anomaly may be categorized as tetralogy of Fallot with DORV or DORV with pulmonary stenosis . Edwards uses still different criteria for distinguishing between these two conditions. Taussig-Bing heart (see description under “ Morphology ” later in this chapter) is defined as “DORV of the TGA type with no pulmonary stenosis (PS)”, in other words, “DORV with Subpulmonary VSD + No PS.” In Taussig-Bing Heart, the aorta and PA arise wholly or nearly so from the RV. If more than 50% of the aorta arises from the RV and more than 50% of the PA arises from the LV in the setting of a VSD, then the diagnosis is TGA+VSD and not DORV.

Because of this differing terminology, surgical reports must clearly describe the entities under discussion. DORV is a descriptive term that is used to refer to an extensive range of cardiac phenotypes in which the great arteries arise wholly or predominantly from the right ventricle. As such, DORV has been difficult to define with precision as demonstrated by the established classifications.

Classification

In 1972, Lev and associates proposed an anatomic classification of DORV based on the relationship between the VSD and the great vessels.

This classification recognized four anatomic types of DORV:

•
DORV with subaortic VSD
•
DORV with doubly committed VSD
•
DORV with subpulmonary VSD (Taussig-Bing Heart)
•
DORV with noncommitted VSD

Functional classification of DORV:

A functional classification was proposed by the International Society for Nomenclature of Pediatric and Congenital Heart Disease (ISNPCHD) and is now part of the International Pediatric and Congenital Cardiac Code (IPCCC) in collaboration with the World Health Organization (WHO) 11th version of the International Classification of Diseases (ICD-11) ^, :

•
DORV with subaortic or doubly committed VSD and no pulmonary stenosis (VSD type)
•
DORV with subaortic or doubly committed VSD and pulmonary stenosis (tetralogy of Fallot type)
•
DORV with subpulmonary VSD (TGA type)
•
DORV with noncommitted VSD

Historical note

Until the middle of the 20th century, DORV was considered a type of transposition, either simple or partial.

When Kirklin performed the first repair of DORV (simple type with a subaortic VSD with no pulmonary stenosis) in May 1957 at the Mayo Clinic, the anomaly was virtually unknown, and the preoperative diagnosis was large VSD with high pulmonary blood flow. Diagnosis was correctly made at operation, the term double outlet right ventricle or origin of both great vessels from the right ventricle coined in the operating room, position of the His bundle deduced, and intraventricular tunnel repair performed in much the same manner as is done today. An identical sequence occurred at Green Lane Hospital in September 1958. Earlier, in 1952, Braun and colleagues reported what was clearly a case of DORV with pulmonary stenosis and used the phrase double outlet ventricle , but the title of their paper was confusing, and it escaped notice. About the time of the first repair, the first morphologic paper with the title “Double Outlet Right Ventricle: a Partial Transposition Complex” was published by Witham, illustrating the challenges in terminology. Subsequently, other early descriptions of the morphology appeared. In 1963, Redo and colleagues also reported repair of this entity.

Taussig-Bing heart was described in 1949, but its place in the spectrum of DORV was not recognized until later. ^, Many early papers understandably referred to it under the heading Transposition . Lev and colleagues recognized it as a form of DORV with subpulmonary VSD. They and earlier workers did not clearly state, however, that Taussig-Bing heart is different from the heart with classic DORV with subaortic VSD, not only with respect to relationships of the VSD but also with respect to position and interrelations of great arteries and infundibular (outlet) septum. Early reports of successful surgical treatment were published in 1967 and 1969. ^, Other early reports of intraventricular tunnel repairs were by Patrick and McGoon in 1968 and by Kawashima and colleagues in 1971. ^,

The other types of DORV with AV concordant connection began to be clarified in the classic paper by Lev and colleagues in 1972. Successful correction of unusual forms was reported in the 1970s and early 1980s.

Morphology and morphogenesis

The basic categorization of Lev and colleagues forms the basis of most surgical thought about this anomaly, but the terms they used, such as “subaortic” and “subpulmonary,” are relational ones. Confusion arises when their terms are used as morphologic ones for actual location of the VSD (see “ Location in Septum and Relationship to Conduction System ” under Morphology in Section I of Chapter 33 ).

According to Sakata, Lecompte, and colleagues, actual categorization of DORV and related conditions (specifically, Taussig-Bing heart, transposition of the great arteries with VSD, and double outlet left ventricle) is less important than a generalized surgical plan for their management. Even so, development of a valid body of knowledge concerning surgical methods and outcomes requires accurate categorization of morphologic details and other patient characteristics. Even with the goal of accurate morphologic categorization and description, problems remain. Although a conus (or infundibulum ) is easy to define as the presence of muscle between a semilunar and AV valve, the muscle strip may vary from a few millimeters to a few centimeters wide. An aorta that is to the right and side by side with the pulmonary trunk may seem essentially normal in position to one observer or in D-malposition to another. These matters complicate categorization accuracy and precision.

Morphogenesis

Complex categorization points to a unifying hypothesis of morphogenesis put forth in a series of papers by the Van Praaghs, summarized recently by Richard Van Praagh. He hypothesizes that “the distal or subsemilunar part of the infundibulum or conus arteriosus performs an arterial switch during cardiogenesis,” with the development stage similar to the Taussig-Bing heart. The developmental steps that avoid DORV relate to asymmetric conal free wall enlargement. Van Praagh proposes that failure of this morphologic step leads to such entities as double outlet right and left ventricle, various transposition entities, and isolated atrial and ventricular discordant connections.

Ventricular septal defect

The VSD is usually large, but in a number of cases it is smaller than the aortic root and flow restrictive. ^, It may be multiple; rarely, it is absent.

In most DORV hearts, the VSD is conoventricular, lying between the limbs of the trabecula septomarginalis (TSM; septal band). ^, However, such defects vary in their relationships with the great arteries. Therefore, the VSD is discussed in relational categories . ^,

Subaortic ventricular septal defect.

The subaortic VSD and TSM lie more posteriorly in the ventricular septum than subpulmonary and doubly committed VSD and are tucked beneath the infundibular (conal) septum ( Fig. 45.2 ). Distance between the VSD and aortic valve varies, depending on presence and length of the subaortic conus (infundibulum); this determines whether the aorta overrides the VSD and hence whether the VSD is juxtaaortic.

An autopsy specimen of the heart shows an open right ventricle in a simple double outlet right ventricle with a subaortic ventricular septal defect, with arrows labeling key structures. The autopsy specimen of a simple double outlet right ventricle with a subaortic ventricular septal defect is shown in an open ventricular view. Several arrows point to labeled structures within the specimen. Two arrows in the upper region point to the pulmonary valve P V. An arrow on the upper left side points to the aortic root A R. A lower left arrow indicates the tricuspid valve T V. An arrows on the right side direct attention to the right ventricle R T and the ventricular septal defect V S D. The specimen demonstrates a prominent subaortic conus and a well-developed infundibular septum separating the pulmonary valve from the aorta, tricuspid valve, and ventricular septal defect, with internal muscular ridges, leaflet tissue, and septal boundaries visible. — • Figure 45.2

When there is aortic-mitral fibrous continuity, absence of a subaortic conus, and a typical juxtaaortic VSD, the posterosuperior margin of the VSD is formed by the left aortic cusp or base of the anterior mitral leaflet, depending on degree of overriding. The ventriculoinfundibular fold and rightward posterior division of the TSM may form the posterior margin of the VSD. Alternatively, the VSD may reach the tricuspid anulus (opposite the anteroseptal leaflet commissure), resulting in mitral-tricuspid continuity, and the VSD is perimembranous ^, (see “ Perimembranous Ventricular Septal Defect ” under Morphology in Section I of Chapter 33 ). In this event, the rightward posterior division of the TSM is deficient, and the bundle of His lies along the posteroinferior border of the VSD and is at risk during surgical repair ^, ( Fig. 45.3 ). Occasionally the VSD may extend farther inferiorly beneath the septal leaflet of the tricuspid valve. Inferiorly, the VSD is bordered by the TSM and anteriorly by the infundibular septum.

A set of three cardiac specimens shows opened right ventricles in a double outlet right ventricle with a subaortic ventricular septal defect, arranged in panels A, B, and C. The set of three cardiac specimens presents a double outlet right ventricle with a subaortic ventricular septal defect, with the right ventricle opened and displayed in panels A, B, and C. In panel A, arrows in the upper left region point to the aorta Ao and aortic valve Ao V, while arrows across the upper region indicate the infundibular septum I S. An arrow on the right side points to the ventricular septal defect V S D, a lower right arrow points to the right ventricle R V, and a lower left arrow indicates the tricuspid valve T V, showing a subaortic conal muscle band separating the aortic and tricuspid valves. In panel B, arrows in the upper left point to the aorta Ao, arrows in the upper right indicate the pulmonary trunk P T, arrows along the right side point to the pulmonary valve P V, an arrow near the mid-right marks the ventricular septal defect V S D, a lower right arrow indicates the right ventricle R V, and a lower left arrow points to the tricuspid valve T V, with additional arrows on the left side indicating the trabecula septomarginalis divisions A and P and an upper central arrow indicating the infundibular septum I S. In panel C, arrows in the upper left region point to the aortic valve Ao V, arrows in the upper central region indicate the infundibular septum I S, arrows on the right side point to the pulmonary valve P V, a mid-right arrow indicates the ventricular septal defect V S D, a lower right arrow marks the right ventricle R V, and a lower left arrow points to the tricuspid valve T V, with a dashed line in the upper central region indicating the position of the suture line for patch repair. — • Figure 45.3

Chordal attachments of anterior and septal tricuspid leaflets are variable; they may be anomalously attached around the edge of the VSD and seriously interfere with placing of the tunnel patch ^, ( Fig. 45.4 ).

A pair of specimens shows opened right-ventricle specimens labeled A and B, each with arrows pointing toward internal cardiac structures. The cardiac specimen of double outlet right ventricle with bilateral conus and a subaortic ventricular septal defect is presented in panels A and B, from a patient with a pulmonary trunk band. In panel A, the right ventricular outflow tract is opened, along with the aortic valve and aorta. An arrow on the right side indicates the ventricular septal defect V S D, which is partially overlaid by chordae attached to the tricuspid valve T V. Arrows in the upper region point to the aorta Ao and aortic valve Ao V, while a lower right arrow indicates the right ventricle R V and a lower left arrow points to the tricuspid valve T V. In panel B, the infundibular septum I S is displaced to the left, revealing the pulmonary valve P V and an extensive subpulmonary conus. Arrows in the upper right region point to the pulmonary valve, while arrows in the mid-right region indicate the ventricular septal defect. A lower right arrow marks the right ventricle, a lower left arrow points to the tricuspid valve, and an arrow toward the upper left central region indicates the infundibular septum, which inserts posteriorly and is shown as unrelated to the interventricular septum. — • Figure 45.4

When DORV is associated with L-malposition of the aorta, the VSD is usually juxtaaortic and thus also subaortic. VSD and TSM, within whose limbs the VSD is cradled, lie more anteriorly and superiorly than when the aorta is to the right. The TSM and its limbs form inferior and posterior margins of the defect, as does the aortic valve superiorly. The VSD occasionally extends to the tricuspid anulus and is perimembranous.

Subpulmonary ventricular septal defect.

Taussig-Bing heart is the typical example of DORV and subpulmonary VSD. ^, ^, ^, ^, It may be considered a form of DORV in which the VSD is subpulmonary and associated with malalignment of the infundibular septum.

The VSD and TSM lie more superiorly and anteriorly in the ventricular septum, directly beneath the pulmonary conus or valve, than they do in subaortic VSD with right-sided aorta, but in a position similar to that of subaortic VSD with aortic L-malposition. If there is a subpulmonary conus, infundibular (conal) muscle forms the superior margin of the defect. If there is no subpulmonary conus, there is pulmonary-mitral and occasionally pulmonary-tricuspid continuity, and the VSD is juxtapulmonary with the pulmonary valve overriding it ( Fig. 45.5 ). The posterosuperior margin of the VSD is formed by the zone of fibrous continuity or by the pulmonary cusps, depending on degree of pulmonary valve overriding, or by the subpulmonary conus if present. As with subaortic VSD, the defect may extend to the tricuspid anulus posteroinferiorly and be perimembranous (see Fig. 45.5 ), but often it does not. The infundibular septum is usually sagittally oriented and is then not a part of the interventricular septum. ^,

A set of cardiac specimens displays a double outlet right ventricle with a subpulmonary ventricular septal defect, as shown in panels A, B, and C, with arrows labeling the internal structures. The set of cardiac specimens of double outlet right ventricle with a subpulmonary ventricular septal defect is presented in panels A, B, and C. In panel A, the right ventricular outflow tract, aortic valve, and aorta are opened. Arrows in the upper left region point to the aorta Ao and aortic valve Ao V, with an arrow across the upper portion indicating the subaortic conus separating the aortic valve from the tricuspid valve T V. An arrow toward the upper right region indicates the rightward aspect of the infundibular septum. A lower right arrow points to the right ventricle R V, and a lower left arrow indicates the tricuspid valve. In panel B, the infundibular septum and adjacent portion of the free wall are displaced toward the aorta. Arrows in the upper left region point to the pulmonary trunk P T, arrows in the upper right region indicate the pulmonary valve P V, and an arrow in the mid-right region marks the I S. Lower region arrows indicate the right ventricle, while an upper central arrow indicates the infundibular septum, which lies in a sagittal plane, has no attachment to the ventricular septum, and separates the ventricular septal defect from the aortic valve, with no subpulmonary conus present. In panel C, the specimen is viewed from the opened left ventricle. An arrow in the upper left region points to the ventricular septal defect V S D, arrows in the upper right region indicate the overriding pulmonary valve P V, an arrow on the right side points to the mitral valve M V, and arrows in the lower region indicate the left ventricle L V, with direct fibrous continuity between the pulmonary valve and the anterior leaflet of the mitral valve. — • Figure 45.5

Doubly committed ventricular septal defect.

In doubly committed VSD, an uncommon variant, the VSD and TSM lie more superiorly in the septum than subaortic or subpulmonary VSDs. This, plus absence (or severe hypoplasia) of the infundibular septum and consequent confluence of the aortic and pulmonary valves, place the defect in a juxtaarterial position. ^, The semilunar valves are related to posterior and superior boundaries of the defect. Anterior and inferior boundaries are formed by the TSM and its left anterior division; posteroinferior boundaries are formed by the posterior division. This muscle band usually separates the VSD from the tricuspid valve anulus. There is usually no conus, but if present it is very hypoplastic, and there may be aortic-tricuspid and pulmonary-mitral continuity ( Fig. 45.6 ).

The VSD and its relationships resemble those of isolated juxtaarterial VSD (see Chapter 33 ), tetralogy of Fallot with juxtaarterial VSD (see Chapter 34 ), and some types of double outlet left ventricle (see Chapter 46 ). Both semilunar valves usually lie over the RV, but it can be difficult to decide whether this is the case or whether they lie mostly over the LV. At times, they may arise equally over both ventricles, a condition that can be called double outlet both ventricles.

Recently, Iyer and colleagues have further reviewed the morphologic and surgical considerations in seven patients with what they also term double outlet both ventricles . These patients constitute a spectrum of malformations ranging from DORV with doubly committed VSD to double outlet left ventricle (DOLV.)

Noncommitted or remote ventricular septal defect.

Trabecular VSDs are not related to the TSM and its divisions, as are VSDs of most hearts with DORV, and they are clearly away from the semilunar valves. However, an inlet septal VSD (see “ Morphology ” in Section I of Chapter 33 ) may be sufficiently remote from the great arteries as to be considered noncommitted ( Fig. 45.7 ).

A pair of specimens shows opened ventricular specimens labeled A and B, each with arrows pointing toward internal cardiac structures. The pair of cardiac specimens presents a double outlet right ventricle with a noncommitted ventricular septal defect, displayed in panels A and B. In panel A, arrows in the upper left region point to the aorta Ao, followed by arrows across the upper region indicating the aortic valve Ao V and the subsemilunar conus. Arrows in the upper right region indicate the banded pulmonary trunk P T and pulmonary valve P V. An arrow in the mid-right region points to the ventricular septal defect V S D. Arrows in the lower region indicate the right ventricle R V, and an arrow on the left side points to the tricuspid valve T V. In panel B, arrows in the upper left region indicate the ventricular septal defect V S D. Arrows in the upper right region point to the anterior mitral valve leaflet ant M V. An arrow in the lower region indicates the left ventricle L V. — • Figure 45.7

Infundibulum

In general, hearts with DORV may have bilateral conuses, one beneath the aortic valve and one beneath the pulmonary valve, or a single conus beneath either semilunar valve, or no conus. Analysis of 42 autopsy specimens at Green Lane Hospital revealed that about three-fourths of hearts with subaortic VSD have bilateral conuses, and about one-fourth have only a subpulmonary conus. An operative experience, however, may reflect a nonrepresentative prevalence of morphologic features. For example, in 350 patients operated on at Madras Medical Mission, the distribution of conal morphology was weighted far more toward absent conus (86%); prevalence of subaortic VSD was 57% (KM Cherian; personal communication, 2000). Hearts with subpulmonary VSD (Taussig-Bing hearts) have either bilateral conus or a single conus beneath the aortic valve, in about equal proportions.

There is a pattern of relations between conus and position of the great arteries . As a general rule, presence of conus beneath a semilunar valve tends to result in an anterior position of the valve and great artery. Absence of conus links semilunar valve and artery to the mitral valve with fibrous continuity, resulting in a posterior position of valve and artery. As a result, degree of conal development beneath the aortic and pulmonary valves fairly well predicts position and relationship of the great arteries. This can be inferred from the Madras experience, in which there is a high prevalence of normally related great arteries and subaortic or absent conus. Anterior position (D-malposition) of the aorta is uncommon (26%) when there are bilateral conuses but common (67%) when there is only a subaortic conus. An anterior position has not been observed to occur with only subpulmonary conus or with no conus. An aorta side by side with or posterior to the pulmonary trunk occurs in all conal patterns.

Great arteries

Both great arteries may lie over the RV in their entirety in the rare instances of DORV with intact ventricular septum and noncommitted VSD. This is often the situation as well when the VSD is subaortic. When the VSD is doubly committed or subpulmonary, there is usually a variable degree of overriding of one or both great arteries over the VSD.

Positional interrelationships of the great arteries are variable in hearts with DORV. Interrelationships are normal or near-normal in most patients with DORV, with the aorta located rightward and posterior relative to the pulmonary trunk ^, ^, Less often, the great arteries are side by side, with the aorta to the right. D-malposition may be present in hearts with DORV, with the aorta anterior and to the right of the pulmonary trunk or at times directly anterior. Rarely, it is anterior and to the left. Occasionally there is L-malposition, with aorta to the left but side by side with the pulmonary trunk.

Although in 77% of hearts with subaortic VSD the aorta is to the right and either side by side or posterior to the pulmonary trunk (more or less normally related), it is anterior (D-malposition) in 23% of cases. Furthermore, more or less normally related great arteries are not unique to hearts with subaortic VSD; those with subpulmonary VSD have normally related great arteries in similar frequency.

Only in hearts with noncommitted VSD is the frequency of more or less normally related great arteries less. Although D-malposition of the aorta may be considered characteristic of ordinary transposition (see “ Great Arteries ” under Morphology in Chapter 44 ) and by implication Taussig-Bing heart, hearts with DORV and subpulmonary VSD are associated with typical D-malposition in a minority of cases.

Hearts with doubly committed VSD tend to have more or less normally related great arteries. Observing great artery position at cineangiography or operation does not permit a reasonably accurate inference as to the position and category of the VSD. There is no greater certainty that the VSD is subaortic when the great arteries are more or less normally interrelated than when in D-malposition. When the aorta is in D-malposition, there is no greater certainty that the VSD will be subpulmonary than subaortic.

Pulmonary stenosis

Pulmonary stenosis is common in hearts with a subaortic VSD. It is most often infundibular ( Fig. 45.8 ), but it may be valvar, with or without a small pulmonary valve ring. Thus, all types of pulmonary stenosis observed in hearts with tetralogy of Fallot may be seen in DORV. Rarely, infundibular stenosis may be of the isolated low-lying variety, producing a two-chambered RV. ^,

A pair of cardiac specimens shows a double outlet right ventricle with a subaortic ventricular septal defect and infundibular pulmonary stenosis, displayed in panels A and B. The pair of cardiac specimens presents a double outlet right ventricle with a subaortic ventricular septal defect and infundibular pulmonary stenosis, displayed in panels A and B. In panel A, arrows in the upper left region point to the aorta Ao, followed by arrows across the upper portion indicating the aortic valve Ao V and the subaortic conus separating the aortic valve from the tricuspid valve T V. Arrows toward the right upper region indicate the pulmonary outflow P T out and the pulmonary valve P V. An arrow in the mid-right region points to the ventricular septal defect V S D. Arrows in the lower region indicate the right ventricle R V, and an arrow on the left side points to the tricuspid valve. In panel B, arrows in the upper left region indicate the aorta Ao. Arrows moving downward indicate the tricuspid valve T V, followed by arrows in the lower region pointing to the right ventricle R V. An arrow near the central region indicates the infundibular septum I S. Arrows in the upper right region point to the pulmonary trunk P T and pulmonary valve P V, and an arrow near the upper central region indicates the ventricular septal defect, through which a probe is shown passing into the aorta. — • Figure 45.8

Pulmonary stenosis is also common in hearts with doubly committed VSD (five of five in the GLH experience). It is uncommon in association with Taussig-Bing heart and in hearts with a noncommitted VSD. ^,

Conduction system

The AV node is in its normal position in the AV septum, and the bundle of His penetrates the right fibrous trigone in the usual way. Thus, the course of the bundle of His relative to the VSD is the same as in primary VSD and in tetralogy of Fallot (see Chapters 33 and 34 ). The bundle is at risk of damage during repair when the defect reaches the tricuspid anulus (and becomes perimembranous). This is true whether the defect is subaortic or subpulmonary and whether the ascending aorta is right or left sided. ^, ^, However, as in other conditions with clockwise rotation and dextroposition of the aorta, the bundle is more on the left ventricular side of the septum than usual. Furthermore, the trigone is often attenuated in DORV when there is a subaortic conus, which removes the aortic anulus from the central fibrous skeleton of the heart.

When a complete AV septal defect coexists, the node and bundle course are altered accordingly (see “ Conduction System ” under Morphology in Chapter 32 ).

Coronary arteries

Coronary artery pattern depends on position of the great arteries. In most varieties of DORV, it is similar to normal except that the aortic sinuses are rotated in a clockwise direction (viewed from below), such that the right coronary arises anteriorly and the left coronary posteriorly. When the aorta is anterior and rightward, the pattern is usually similar to that in transposition of the great arteries (see “ Coronary Arteries ” under Morphology in Chapter 44 ), with the right coronary artery arising from sinus 2 (right posterior facing sinus). ^, In 15% of cases, a single coronary ostium may arise either anteriorly or posteriorly that supplies left and right sides of the heart. ^, The branching pattern is also usually normal, except for occasional origin of the left anterior descending from the right coronary artery, with this vessel crossing the right ventricular outflow from right to left as in tetralogy of Fallot (see Chapter 34 ). This anomaly was found in 25% of the DORV hearts reported in the early Mayo Clinic series, but it was not encountered in 42 GLH autopsy cases.

When the aorta is to the left in L-malposition, the right coronary artery passes to the right from the anterior sinus of the leftward anterior aorta to reach the AV groove in front of the pulmonary trunk. Its position prohibits extensive anterior patching across the pulmonary “anulus.”

Associated anomalies

Major associated cardiac anomalies, in addition to pulmonary stenosis of the tetralogy of Fallot type, may coexist. Coarctation of the aorta and hypoplastic aortic arch may be present, particularly in Taussig-Bing variant, and may require concomitant repair in the neonatal period; rarely, discrete subvalvar aortic stenosis may coexist. ^, Various other cardiac anomalies coexist in about 30% of patients coming to intracardiac repair of DORV with a subaortic or doubly committed VSD.

Morphologic syndromes of double outlet right ventricle

Double outlet right ventricle with subaortic ventricular septal defect.

Double Outlet Right Ventricle with subaortic VSD is commonly occurring. In the absence of pulmonary stenosis it is referred to as VSD type. In the presence of pulmonary stenosis it is referred to as of the tetralogy of Fallot type. The aorta is to the right, usually by the side of the pulmonary trunk or slightly posterior to it, or which in about 20% of cases is somewhat anterior to the pulmonary trunk. The aorta may spiral around the pulmonary trunk as it leaves the heart, or the great arteries may course parallel to each other. Usually there is a conus (infundibulum) beneath both the aorta and pulmonary valve, but in some cases there may be no subaortic conus. Coronary arterial anatomy is normal.

In borderline cases, this type of DORV merges with the type in which a perimembranous VSD demonstrates inlet extension and appears to be noncommitted and, on the other hand, the type in which the VSD demonstrates outlet extension and appears to be doubly committed.

Double outlet right ventricle with subpulmonary ventricular septal defect (Taussig-Bing heart).

In the most representative cases, the Taussig-Bing heart is similar from heart to heart. The VSD is anterior and superior and subpulmonary. The left main coronary artery is anterior to the pulmonary trunk. The pulmonary trunk arises biventricularly over the VSD, and the aorta is to the right and slightly anterior to or alongside it. The first portions of aorta and pulmonary trunk are parallel rather than tending to spiral as do normally positioned great arteries. ^, ^, The infundibular septum is in the sagittal plane and is not part of the interventricular septum. Lev and colleagues were able to use specific morphologic features within the RV as the hallmark of Taussig-Bing heart, but this is rarely possible clinically or surgically.

Subaortic stenosis, from narrowing of the subaortic infundibulum, may develop in Taussig-Bing heart. Pulmonary stenosis is uncommon. The mitral valve may straddle the subpulmonary VSD, and in such cases the LV may be hypoplastic. ^, Associated coarctation of the aorta and hypoplastic aortic arch is common (about 50% of cases). ^, ^, ^, This contrasts with the 6% prevalence in transposition with VSD.

In borderline cases, this type of DORV merges with transposition of the great arteries and large VSD and, on the other hand, may merge with DORV and noncommitted VSD of the trabecular type.

Double outlet right ventricle with doubly committed ventricular septal defect.

In DORV with doubly committed VSD, an uncommon syndrome, the VSD is immediately beneath both aorta and pulmonary trunk and is juxtaarterial. The infundibular septum is either absent or severely hypoplastic.

Double outlet right ventricle with noncommitted ventricular septal defect.

When the VSD is in the trabecular septum and clearly far removed from the great arteries, the anomaly is easily categorized into this subset. When the VSD is in the inlet septum and up against the tricuspid valve, categorization as DORV with noncommitted VSD can be questioned, but at least the defect is further removed from the aorta than in most hearts with DORV and subaortic VSD.

Double outlet right ventricle with L-malposition.

DORV with L-malposition usually has a subaortic VSD (rarely extending back to the tricuspid anulus) and pulmonary stenosis and presents a rare but distinctive clinical and surgical syndrome. ^, ^, Rarely the VSD may be perimembranous and extend up toward the pulmonary valve, or it may be truly subpulmonary. The VSD may, contrariwise, extend into the inlet septum and be noncommitted. Mehrizi has reported DORV with L-malposition and doubly committed VSD.

Double outlet right ventricle with complete atrioventricular septal defect.

In cases of DORV with complete AV septal defect, the interventricular communication is in the inlet and usually has a subaortic extension beneath a bridging left superior leaflet (see “ Atrioventricular Valves ” under Morphology in Chapter 32 ). According to Bharati and colleagues, in almost half of the cases the inlet interventricular communication is noncommitted with no subaortic extension.

Double outlet right ventricle with superior-inferior ventricles.

In most hearts with this ventricular position, there is a ventricular L-loop, atrial situs solitus, and AV discordant connection (see Chapter 47 ). Uncommonly, in DORV with atrial situs solitus, AV concordant connection, and D-ventricular loop, there is a positional anomaly termed superior-inferior ventricles (over-and-under ventricles , upstairs-downstairs ventricles) (see Chapter 26 ). The RV is superior (and sometimes a little posterior) and the LV inferior. There may be D- or L-malposition of the aorta. The VSD is usually perimembranous and in the inlet portion of the septum. The right AV valve is usually more superiorly placed than usual relative to the left AV valve, and either AV valve may straddle the VSD (see “ Ventricular Septal Defect with Straddling or Overriding Tricuspid Valve ” in Chapter 33 ). Severe left ventricular hypoplasia may be present, and pulmonary stenosis is common.

Clinical features and diagnostic criteria

Pathophysiology

Clinical features of patients with this morphologically highly variable anomaly are necessarily also highly variable. In general, patients with a large VSD and no pulmonary stenosis or severe pulmonary vascular disease are not clinically cyanotic. This is because pulmonary blood flow is high and the resultant mixture of blood in the RV has a high enough oxygen saturation to prevent clinically evident cyanosis; however, there is some arterial desaturation.

Streaming of blood flow.

Pulmonary blood flow is also affected by streaming of blood within the RV, which is determined by the relationship of the semilunar valves to the VSD and the position and presence of the infundibular septum. ^, Thus, in DORV with subaortic VSD and no pulmonary stenosis, the flow of highly oxygen-saturated left ventricular blood through the VSD is directed preferentially beneath the infundibular septum into the adjacent aorta (particularly when the subaortic conus is short or absent), whereas systemic venous blood passes largely out of the pulmonary trunk. As a result, patients with this arrangement present in infancy with high pulmonary blood flow in heart failure without cyanosis and cannot be clinically distinguished from infants with a large VSD.

When the VSD is subpulmonary, as in Taussig-Bing heart, flow through it of highly saturated left ventricular blood is directed into the adjacent pulmonary trunk by the vertically positioned infundibular septum. Pulmonary blood flow is then higher than systemic blood flow, with systemic venous blood from the RV tending to flow more into the aorta. This situation is aggravated when there is overriding of the pulmonary trunk onto the LV. Thus, these infants present in a fashion similar to patients with transposition of the great arteries with large VSD in heart failure with mild cyanosis.

Pulmonary vascular disease.

The development of pulmonary vascular disease may be more rapid in onset in patients with DORV without pulmonary stenosis than in patients with simple large VSD, particularly in Taussig-Bing heart. The resultant reduction in pulmonary blood flow has a more marked influence on Sao ₂ than in simple VSD, because it reduces the amount of highly saturated blood in a common mixing chamber.

Pulmonary stenosis.

When important pulmonary stenosis is present, cyanosis becomes severe, and the clinical features and presentation are similar to those of patients with tetralogy of Fallot (see Chapter 34 ).

Examination

On physical examination, no clinical signs distinguish patients with DORV with and without pulmonary stenosis from the conditions that they mimic. The electrocardiogram (ECG) is not diagnostic, nor is the chest radiograph. However, in those uncommon instances in which there is L-malposition of the aorta, the aorta may be evident on the posteroanterior chest radiograph as it ascends vertically from the cardiac silhouette in the left upper mediastinum ^, ; this finding is not specific, however.

Echocardiography

Two-dimensional echocardiography provides a considerable amount of information regarding size of the VSD, relationship of the VSD to the semilunar valves, presence of subvalvar conus, and AV valve abnormalities. ^, ^, Position of the great arteries and conus are usually apparent ( Fig. 45.9 ). The coronary arterial anatomy can also generally be defined accurately in neonates and infants by echocardiography alone.

An echocardiogram in a subxiphoid view shows a double outlet right ventricle of the Taussig-Bing type with labeled cardiac structures. The echocardiogram in a subxiphoid view presents a double outlet right ventricle of the Taussig-Bing type with labeled cardiac structures. The great arteries are shown in a side-by-side relationship, with the pulmonary trunk positioned closest to the left ventricle. The ventricular septal defect is subpulmonary, and a prominent subarterial conus is visible. In the labeled image, the sequence begins at the lower left with the right atrium R A, continues to the aorta Ao near the central region, then to the pulmonary trunk P T toward the upper right, followed by the subarterial conus C in the mid-right region, and ends with the right ventricle R V positioned at the lower right portion. The aorta appears smaller than the pulmonary trunk, suggesting an associated aortic arch abnormality. — • Figure 45.9

Cardiac catheterization and cineangiography

Because echocardiographic assessment of morphology is reliable, cardiac catheterization before surgical intervention is not routinely required in neonates and young infants. In older infants and children, it may be needed to assess hemodynamics such as pulmonary vascular resistance and ventricular end-diastolic pressure, and to define extracardiac morphology such as the peripheral pulmonary vasculature and presence of aortopulmonary collateral vessels. Cineangiography can be used when necessary to define intracardiac morphology ( Fig. 45.10 ). The whole of the ventricular septum must be profiled so that its upper part can be projected cranially. In this way, great vessel positions can be assessed relative to the two ventricles, and location of the VSDs determined. ^, VSD size can be judged ( Fig. 45.11 ) and subsets such as Taussig-Bing heart identified ( Fig. 45.12 ). Cineangiography is of particular value in assessing the complex interrelationships present in DORV with superior-inferior ventricles and crisscross hearts.

A set of cineangiograms and cardiac specimens shows a simple double outlet right ventricle with a conoventricular ventricular septal defect, displayed across panels A through F. The set of cineangiograms and cardiac specimens presents a simple double outlet right ventricle with a conoventricular ventricular septal defect, displayed across panels A through F. In panel A, a left ventriculogram in an elongated right anterior oblique view shows the infundibular septum I S, with the aorta Ao labeled in the upper left region, the pulmonary trunk P T in the upper right region, and the left ventricle L V in the lower right region. In panel B, a four-chamber view shows the ventricular septal defect V S D abutting the tricuspid valve T V. Labels identify the aorta in the upper left region, the mitral valve M V in the upper right region, the right ventricle R V in the lower left region, and the left ventricle in the lower right region. In panel C, arrowheads along the mid-left region indicate separation between the ventricular septal defect and the tricuspid valve by a bar of muscle, with the aorta labeled along the left margin and the left ventricle positioned in the lower right region. In panel D, a subsequent frame from the same cineangiogram shows the pulmonary artery labeled in the upper left region, the aorta along the left border, and the left ventricle in the lower right region. In panel E, a specimen illustrating a double outlet right ventricle similar to panels C and D is viewed from the left ventricular aspect, with the ventricular walls opened and no internal labels shown. In panel F, the same specimen is viewed from the right ventricular aspect, with labels indicating the aorta in the upper region, the tricuspid valve in the left central region, the right ventricle in the lower region, and the ventricular septal defect on the right side, marked by an arrow, demonstrating a muscular rim separating the ventricular septal defect from the tricuspid valve. — • Figure 45.10

A pair of cineangiograms shows a simple double outlet right ventricle with a restrictive subaortic ventricular septal defect, displayed in early and late phases as panels A and B. The pair of cineangiograms presents a simple double outlet right ventricle with a restrictive subaortic ventricular septal defect, shown in an early phase panel A and a late phase panel B following contrast injection into the left ventricle in a long axial projection. In panel A, labels in the upper left region indicate the aorta Ao, while labels in the upper right region indicate the pulmonary trunk P T. The left atrium L A is labeled in the mid-right region, with the mitral valve M V positioned just below it. The left ventricle L V occupies the lower right region, and the right ventricle R V is labeled in the lower left region. An arrow near the central lower region adjacent to the right ventricle indicates the restrictive subaortic ventricular septal defect. In panel B, labels again identify the aorta Ao in the upper left region and the left atrium L A in the mid-right region. The left ventricle L V remains labeled in the lower right region, with the right ventricle R V in the lower left region. An arrow in a similar central lower position marks the ventricular septal defect in the late phase, demonstrating persistent contrast passage across the defect. — • Figure 45.11

A pair of cineangiograms shows a Taussig-Bing heart in elongated right anterior oblique and long axial views, displayed as panels A and B with labeled cardiac structures. The pair of cineangiograms presents a Taussig-Bing heart shown in an elongated right anterior oblique view in panel A and a long axial view in panel B. In panel A, labels in the upper left region indicate the aorta Ao, while labels in the upper right region indicate the pulmonary trunk P T. The tricuspid valve T V is labeled in the mid-left region, and the right ventricle R V occupies the lower region. In panel B, the aorta Ao is labeled in the upper left region and the pulmonary trunk P T in the upper right region. The infundibular septum I S is labeled in the mid-left region, positioned between the aorta and pulmonary trunk and shown as not interventricular in location. The tricuspid valve T V is labeled in the left central region, the right ventricle R V in the lower left region, the mitral valve M V in the mid-right region, and the left ventricle L V in the lower right region. Two arrows between the tricuspid and mitral valves indicate the ventricular septal defect, with the pulmonary trunk shown as partially overriding this region. — • Figure 45.12

Natural history

The natural history of patients with DORV and AV concordant connection is highly variable, but some general trends can be identified.

The natural history of DORV, Subaortic VSD without pulmonary stenosis is similar to that of simple large VSD (see “ Natural History ” in Section I of Chapter 33 ); this is probably also true for patients with DORV whose VSD is doubly committed or noncommitted. The exception is that spontaneous VSD closure, which is fatal rather than curative, is rare in DORV.

When the VSD is subpulmonary, as in Taussig-Bing heart, the natural history is similar to that for transposition and large VSD, but it is even more unfavorable (see “ Ventricular Septal Defects ” under Natural History in Chapter 44 ). This is in part because severe pulmonary vascular disease occurs early in life. Poor prognosis for these patients may also be related to frequent occurrence of left-sided obstructions, such as subaortic stenosis, coarctation of the aorta, hypoplastic aortic arch and left ventricular and mitral valve hypoplasia (see “ Coarctation as Part of Hypoplastic Left Heart Syndrome ” under Morphology in Section I of Chapter 40 ).

When pulmonary stenosis or atresia is present in DORV with subaortic VSD, and probably in those with doubly committed or noncommitted VSD as well, the natural history is indistinguishable from that of patients with tetralogy of Fallot and pulmonary stenosis or atresia (see Chapters 34 and 35 ).

The natural history in some patients is dominated by an associated cardiac anomaly, such as a complete AV septal defect (see “ Natural History ” in Chapter 32 ).

Technique of operation

The type of operation selected depends in part on position of the VSD, its relationship to the great arteries, size of the patient, and adequacy of the resulting ventricles and their respective outflows after closing or baffling the VSD and the presence or absence of pulmonary stenosis.

In general:

•
Subaortic VSD, without pulmonary stenosis with an adequate tricuspid to pulmonary valve distance is treated by an intraventricular baffling that directs left ventricular blood through the VSD to the aorta (intraventricular tunnel repair).
•
Subaortic VSD, with pulmonary stenosis with an adequate tricuspid to pulmonary valve distance is treated by an intraventricular baffling that directs left ventricular blood through the VSD to the aorta (intraventricular tunnel repair). In addition, the pulmonary outflow tract stenosis must be relieved as in repair of tetralogy of Fallot (described in “Technique of Operation” in Section I of Chapter 34 ).
•
Subpulmonary VSD, as in Taussig-Bing heart, without pulmonary stenosis is treated with an arterial switch procedure with tunneling the VSD from the LV to the pulmonary (neoaortic) valve. If present, subaortic stenosis and aortic arch obstruction must be also repaired. Uncommonly, intraventricular tunnel from VSD to aorta may be possible in an older child.
•
Blood flow in doubly committed VSDs is usually baffled using a more complex patch from LV to aorta. The superior anchoring of the VSD patch may involve the semilunar valve confluence. Great care must be exercised not to adversely affect semilunar valve function.

Noncommitted VSD may be treated by baffling of blood through the VSD to the aorta, accompanied by myocardial flap reinsertion of the straddling tricuspid valve. If the pulmonary valve is closer to the non-committed VSD and if there is no pulmonary stenosis, the repair consists of tunneling VSD to pulmonary artery with an arterial switch, as reported by Lacour-Gayet and colleagues.

•
If biventricular repair is not possible, a Fontan procedure is considered.

Various surgical procedures are described, but description does not imply recommendations. Indications are described later in this chapter under “Indications for Operation.” Only the general methods are described here, and each patient may be sufficiently unique to require an individual approach.

Intraventricular tunnel repair of double outlet right ventricle, subaortic ventricular septal defect without pulmonary stenosis

Only gold members can continue reading. Log In or Register to continue

Stay updated, free articles. Join our Telegram channel

Tags: Christo I. Tchervenkov, Jeffrey P. Jacobs; Hiromi Kurosawa, Kirklin/Barratt-Boyes Cardiac Surgery

Apr 21, 2026 | Posted by drzezo in CARDIAC SURGERY | Comments Off

Thoracic Key

Fastest Thoracic Insight Engine