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Intraventricular repair of transposition of the great arteries
Intraventricular repair of transposition of the great arteries Dwight C. McGoon, M.D., Rochester, Minn.
A
xTL truly curative operation for transposition of the great arteries would seem to be attainable, save for one problem. To divide the great arteries, rotate or contrapose them, and then reanastomose them is simple in concept and technique and would be totally corrective except that the coronary arteries then would originate from the pulmonary artery, a situation incompatible with life. Because the solution to this problem has not been found, a palliative type of correction,1 namely intra-atrial transposition of venous return, 2 ' 6 has become the accepted treatment. The theoretic feasibility and advantage of an intraventricular repair of transposition of the great arteries for several years has prompted a search for suitable patients for this repair. The first such operation is reported herein. A prerequisite to this repair is the presence of an extra large ventricular septal defect, that is, one representing complete absence of the basal portion of the ventricular septum, both posteriorly (membranous septum) and anteriorly (conal septum, absence of the crista supraventricularis). Embryologically, the conal septum develops as a part of the continuous spiraling conotruncal septum which directs blood flow from a given ventricle to the appropriate great artery. In the present condition, the complete absence of the conal septum From the Mayo Clinic and Mayo Foundation, Rochester, Minn. 55901 Received for publication April 12, 1972.
430
offers the opportunity to correct the hemodynamic abnormality resulting from transposition of the great arteries by the surgical placement of a spiraling prosthetic conal septum so that a given ventricle will empty into its appropriate great artery. Case report CASE 1. A 2-year-old boy was first seen at the Mayo Clinic in March 1969. He had been cyanotic and in congestive heart failure for the first few days of life and was treated with digitalis. Pneumonia developed four times during the first year of life, and there was a chronic cough, with wheezing, tachypnea, and increased perspiration. At examination, the edge of the liver was 5 cm. below the right costal margin. The heart was overactive and to the right. There was a Grade 4 systolic ejection murmur just to the right of the midsternum. A roentgenogram revealed that the heart was enlarged (cardiothoracic ratio of 0.67) and that the vascularity of the lungs was considerably increased. Data obtained at cardiac catheterization (Tables I and II) established the following diagnoses: dextrocardia with situs solitus of the atria and ventricles, ventricular and atrial septal defects, and transposition of the great arteries with subpulmonic stenosis. A left hemiparesis was noted after catheterization. Because of this and an untimely respiratory infection, operation was not undertaken until August, 1969. At operation, a median sternotomy was made. Cardiac pressures were measured (Table I). After heart-lung bypass was instituted in the usual manner, a transverse incision was made in the outflow portion of the right ventricle. The intracardiac anatomy was defined with care. The right ventricle was hypertrophied and its chamber was small. A finger could readily be passed through the pulmonary valve and pulmonary artery. A very large ventricular septal defect was present,
Volume 64
431
Intraventricular repair of TGA
Number 3 September, 1972
Table I. Findings of cardiac catheterization and operation Preoperative catheterization
mm. Femoral artery Left ventricle Pulmonary artery Right ventricle (downstream)* Right ventricle Right ventricle (upstream)* Left atrium Right atrium Superior vena cava Inferior vena cava
Hg
112/58 97/11-17 42/24
-
Postoperative catheterization
Intraoperative
Per cent oxygen saturation
Before repair {mm. Hg)
-
87 97 88
75/5 40/14
After repair (mm Hg)
-
mm.
Hg
Per cent oxygen saturation
100/0 18/7
98/52
94
20/10
67
-
-
96/4-8
71
-
-
-
21/4 43/2
-
-
-
-
60/5 5 20/10
70/2
-
23/16 13/4
97 60 57 58
75/5 30/10 22/14
-
17/7
67 78
-
•Downstream and upstream refer to relationship of the site measured to the patch closing the ventricular septal defect.
extending from the tricuspid annulus to the anterior heart wall. There was direct continuity between the mitral and pulmonary valves. A large patch of intracardiac knitted Teflon was fashioned to a size appropriate to allow it to form the new spiraling septum of the conus (Fig. 1). The shape of the patch in this patient was oval, but experience from later laboratory investigations7 has revealed the superiority of a boomerang-shaped patch in order to avoid encroachment on either outflow tract. This improved patch is shown in the illustrations. Suturing of the patch was begun posteriorly in exactly the same manner as for the first step in the closure of an ordinary posterior ventricular septal defect, by attaching the patch to the base of the adjacent leaflet of the tricuspid valve (Fig. 2, left). Three appropriately positioned mattress sutures were used for this purpose to attach the posterior aspect of the patch in such a way that the sutures avoided the main bundle of His and its left bundle branches. Next, as for closure of the usual ventricular septal defect, further simple interrupted sutures were placed caudally to attach the patch to the right aspect of the ventricular septum between the previously placed sutures and the papillary muscle of the conus. These sutures grasped only the right aspect of the septum and did not penetrate the septum (Fig. 2, left, represented by dots), thus avoiding injury to the left bundle branches. The next step was the first that is unique to the present procedure. In contrast to the usual repair of a ventricular septal defect, in which the patch is attached to the right of the semilunar valve orifice that drains the left ventricle (in this case the pulmonary valve), the patch was next
Table II. Further catheterization data Preoperative Postoperacatheteriza- tive catheterization tion Systemic flow (L./min./ sq. mm.)
Pulmonary flow Systemic resistance (units sq. M.)
2.9
3.6
9.3
3.6
26.2
16.0
Pulmonary resistance (units sq. M.)
3.2
3.0
Pulmonary-to-systemic flow ratio
3.2
1.0
Pulmonary-to-systemic resistance ratio
0.1
0.1
Dye-dilution curves
Common mixing at ventricular level
Normal
attached to the base of the anterior leaflet of the mitral valve dorsally and interiorly to the semilunar valve (pulmonary valve in this case) (Fig. 1, follow dashed line encircling the patch). The suturing was thus carried deeply into the heart to the left wall of the outflow portion of the left ventricle. The suturing then followed the annulus of the posterior semilunar valve (pulmonary valve) around its left margin and anteriorly onto the fibrous or muscular tissue which separated the posterior (pulmonary) and anterior (aortic)
The Journal of Thoracic and Cardiovascular Surgery
4 3 2 McGoon
Anterior wall of right ventricle Lateral ,--^;.T-J:-^ wall J.-' ' """^i^ Aortic valve
1
^
V-_
Crista Pulmonar annulus
'
*V= Pulmonary v a l v e -
SB' '; V Anterior leaflet of_ tricuspid valve
B.| r IN
J
-_ i Ventricular septum
~>Anterior leaflet of 1 1 mitral 1 valve ^Rim of VSD
Fig. 1. Anatomy of transposition of the great arteries associated with large basilar ventricular septal defect. Line and sites of attachment of knitted Teflon patch, and its preferred shape, are shown. valves. Thus the patch now was being attached from left to right between the semilunar valves. When the suturing reached the right extremity of the ridge of tissue between the semilunar valves, the patch was next attached to the right wall of the outflow tract of the right ventricle along a line that extended to the right extremity of the ventriculotomy (Fig. 2, middle). This long suture line was terminated. Suturing was next resumed along the ventricular septum, beginning now where the attachment had been completed near the papillary muscle of the conus and continuing along the caudal margin of the septal defect and the left anterior aspect of the right ventricle until the left extremity of the ventriculotomy was reached (Fig. 2, middle). The final step was the attachment of the anterior margin of the patch between the lips of the ventriculotomy, incorporating the patch in the suture line used to close the ventriculotomy. Perfusion lasted 102 minutes, and the ascending aorta had been cross-clamped on five occasions, lasting from 4 to 17 minutes each and totalling 61 minutes. Between two of the periods of aortic cross-clamping, the secundum atrial septal defect had been closed by direct suture, via a right atriotomy. After the operation, respiratory distress re-
quired maintenance of assisted ventilation via the endotracheal tube for 30 hours. The hemodynamic status was satisfactory, but digitalis was administered. The recovery was uneventful, and the patient was dismissed from the hospital 11 days after operation. He returned 3 months later at our request for postoperative cardiac catheterization. In the interim, his preoperative symptoms had not recurred, he was normally active, and he had gained 6 pounds. A Grade 3 systolic murmur was present along the right sternal border. The catheterization showed correction of the defects (Tables I and II), save for hemodynamically significant residual subpulmonic stenosis. The angiocardiogram suggested that the repair was satisfactory; the child has remained clinically well 2Vi years after operation. CASE 2. A similar though unsuccessful operation was performed in February, 1971. The patient was 11 years old and had a patent ductus and not an atrial septal defect. There was no pulmonary stenosis, but in other respects there was a striking similarity with the first patient. The technique of repair was similar, except that there was more difficulty in avoiding bulging of the patch into the subpulmonic flow pathway. (The shape of the patch in Figs. 1 and 2 had not yet been
Volume 64
Intraventricular repair of TGA
Number 3
433
September, 1972
Pulmonary valve Aortic valve
Fig. 2. Left, Initial attachment of patch is same as for any posterior high ventricular septal defect. Middle and right, Subsequent steps in attachment of patch (see text for description). developed in the laboratory.7) Ventricular systolic pressures were equal after repair, at 85 mm. Hg, and a gradient of 25 mm. Hg existed between the right ventricle and the pulmonary artery. The patient died after a difficult 48 hour period that was characterized by intermittent low cardiac output. At autopsy, the left ventricular outflow tract was adequate (1 cm. in diameter), but the right ventricular outflow tract had narrowed to a diameter of 7 mm. Death was believed due to a combination of subpulmonic stenosis and pulmonary vascular obstructive disease.
Comment The concept of intraventricular repair of transposition of the great arteries, as reported herein, undoubtedly evolved as a result of stepwise successful correction of increasingly severe degrees of transposition: first the usual form of origin of both great arteries from the right ventricle, 8 - 9 then origin of both great vessels from the right ventricle associated with transposition of the great arteries and posterior ventricular
septal defect (Taussig-Bing variant 10 ), and now transposition of the great arteries with a large basal ventricular septal defect. Should late follow-up of patients who have undergone intra-atrial transposition of venous return for transposition of the great arteries show a significant incidence of tricuspid valvular insufficiency or right ventricular failure, there may be reason to explore the application of the presently reported technique. It is possible that, in patients with transposition of the great arteries who have only a posteriorly located ventricular septal defect or even no ventricular septal defect, a large ventricular septal defect of the type encountered in our patient could be created. Summary Intra-atrial transposition of venous return allows functional but not anatomic correction of transposition of the great arteries.
The Journal of
4 34
McGoon
Thoracic and Cardiovascular Surgery
A more nearly anatomic correction, performed within the ventricles, is described. The method involves replacement of the basal portion of the ventricular septum with a prosthetic septum in such a way that the reconstructed septum has a spiral configuration. The outflow of the left ventricle thus ends in the aorta and that of the right ventricle in the pulmonary artery. The first of two such operations has provided clinical success during a follow-up period of 2Vi years, although a moderate gradient exists between the right ventricle and the pulmonary artery. REFERENCES 1 McGoon, D. C : Surgery for Transposition of the Great Arteries (Editorial), Circulation. In press. 2 Albert, H. M.: Surgical Correction of Transposition of the Great Vessels, Surg. Forum 5: 74, 1955. 3 Merendino, K. A., Jesseph, J. E., Herron, P. W., Thomas, G. I., and Vetto, R. R.: Interatrial Venous Transposition: A One-Stage Intracardiac Operation for the Conversion of
Complete Transposition of the Aorta and Pulmonary Artery to Corrected Transposition: Theory and Clinical Experience, Surgery 42: 898, 1957. 4 Senning, A.: Surgical Correction of Transposition of the Great Vessels, Surgery 45: 966, 1959. 5 Shumacker, H. B, Jr.: A New Operation for Transposition of the Great Vessels, Surgery 50: 773, 1961. 6 Mustard, W. T., Keith, J. D., Trusler, G. A., Fowler, R., and Kidd, L.: The Surgical Management of Transposition of the Great Vessels, J. THORAC. CARDIOVASC. SURG. 48: 953,
1964.
7 Puga, F., and McGoon, D. C : Experimental Correction of Transposition of the Great Arteries. Unpublished data. 8 McGoon, D. C : Origin of Both Great Vessels From the Right Ventricle, Surg. Clin. North Am. 41: 1113, 1961. 9 Kirklin, J. W., Harp, R. A., and McGoon, D. C : Surgical Treatment of Origin of Both Vessels From the Right Ventricle, Including Cases of Pulmonary Stenosis, J. THORAC. CARDIOVASC. SURG. 48: 1026,
1964.
10 Patrick, D. L., and McGoon, D. C : An Operation for Double-Outlet Right Ventricle With Transposition of the Great Arteries, J. Cardiovasc. Surg. (Torino) 9: 537, 1968.
A
xTL truly curative operation for transposition of the great arteries would seem to be attainable, save for one problem. To divide the great arteries, rotate or contrapose them, and then reanastomose them is simple in concept and technique and would be totally corrective except that the coronary arteries then would originate from the pulmonary artery, a situation incompatible with life. Because the solution to this problem has not been found, a palliative type of correction,1 namely intra-atrial transposition of venous return, 2 ' 6 has become the accepted treatment. The theoretic feasibility and advantage of an intraventricular repair of transposition of the great arteries for several years has prompted a search for suitable patients for this repair. The first such operation is reported herein. A prerequisite to this repair is the presence of an extra large ventricular septal defect, that is, one representing complete absence of the basal portion of the ventricular septum, both posteriorly (membranous septum) and anteriorly (conal septum, absence of the crista supraventricularis). Embryologically, the conal septum develops as a part of the continuous spiraling conotruncal septum which directs blood flow from a given ventricle to the appropriate great artery. In the present condition, the complete absence of the conal septum From the Mayo Clinic and Mayo Foundation, Rochester, Minn. 55901 Received for publication April 12, 1972.
430
offers the opportunity to correct the hemodynamic abnormality resulting from transposition of the great arteries by the surgical placement of a spiraling prosthetic conal septum so that a given ventricle will empty into its appropriate great artery. Case report CASE 1. A 2-year-old boy was first seen at the Mayo Clinic in March 1969. He had been cyanotic and in congestive heart failure for the first few days of life and was treated with digitalis. Pneumonia developed four times during the first year of life, and there was a chronic cough, with wheezing, tachypnea, and increased perspiration. At examination, the edge of the liver was 5 cm. below the right costal margin. The heart was overactive and to the right. There was a Grade 4 systolic ejection murmur just to the right of the midsternum. A roentgenogram revealed that the heart was enlarged (cardiothoracic ratio of 0.67) and that the vascularity of the lungs was considerably increased. Data obtained at cardiac catheterization (Tables I and II) established the following diagnoses: dextrocardia with situs solitus of the atria and ventricles, ventricular and atrial septal defects, and transposition of the great arteries with subpulmonic stenosis. A left hemiparesis was noted after catheterization. Because of this and an untimely respiratory infection, operation was not undertaken until August, 1969. At operation, a median sternotomy was made. Cardiac pressures were measured (Table I). After heart-lung bypass was instituted in the usual manner, a transverse incision was made in the outflow portion of the right ventricle. The intracardiac anatomy was defined with care. The right ventricle was hypertrophied and its chamber was small. A finger could readily be passed through the pulmonary valve and pulmonary artery. A very large ventricular septal defect was present,
Volume 64
431
Intraventricular repair of TGA
Number 3 September, 1972
Table I. Findings of cardiac catheterization and operation Preoperative catheterization
mm. Femoral artery Left ventricle Pulmonary artery Right ventricle (downstream)* Right ventricle Right ventricle (upstream)* Left atrium Right atrium Superior vena cava Inferior vena cava
Hg
112/58 97/11-17 42/24
-
Postoperative catheterization
Intraoperative
Per cent oxygen saturation
Before repair {mm. Hg)
-
87 97 88
75/5 40/14
After repair (mm Hg)
-
mm.
Hg
Per cent oxygen saturation
100/0 18/7
98/52
94
20/10
67
-
-
96/4-8
71
-
-
-
21/4 43/2
-
-
-
-
60/5 5 20/10
70/2
-
23/16 13/4
97 60 57 58
75/5 30/10 22/14
-
17/7
67 78
-
•Downstream and upstream refer to relationship of the site measured to the patch closing the ventricular septal defect.
extending from the tricuspid annulus to the anterior heart wall. There was direct continuity between the mitral and pulmonary valves. A large patch of intracardiac knitted Teflon was fashioned to a size appropriate to allow it to form the new spiraling septum of the conus (Fig. 1). The shape of the patch in this patient was oval, but experience from later laboratory investigations7 has revealed the superiority of a boomerang-shaped patch in order to avoid encroachment on either outflow tract. This improved patch is shown in the illustrations. Suturing of the patch was begun posteriorly in exactly the same manner as for the first step in the closure of an ordinary posterior ventricular septal defect, by attaching the patch to the base of the adjacent leaflet of the tricuspid valve (Fig. 2, left). Three appropriately positioned mattress sutures were used for this purpose to attach the posterior aspect of the patch in such a way that the sutures avoided the main bundle of His and its left bundle branches. Next, as for closure of the usual ventricular septal defect, further simple interrupted sutures were placed caudally to attach the patch to the right aspect of the ventricular septum between the previously placed sutures and the papillary muscle of the conus. These sutures grasped only the right aspect of the septum and did not penetrate the septum (Fig. 2, left, represented by dots), thus avoiding injury to the left bundle branches. The next step was the first that is unique to the present procedure. In contrast to the usual repair of a ventricular septal defect, in which the patch is attached to the right of the semilunar valve orifice that drains the left ventricle (in this case the pulmonary valve), the patch was next
Table II. Further catheterization data Preoperative Postoperacatheteriza- tive catheterization tion Systemic flow (L./min./ sq. mm.)
Pulmonary flow Systemic resistance (units sq. M.)
2.9
3.6
9.3
3.6
26.2
16.0
Pulmonary resistance (units sq. M.)
3.2
3.0
Pulmonary-to-systemic flow ratio
3.2
1.0
Pulmonary-to-systemic resistance ratio
0.1
0.1
Dye-dilution curves
Common mixing at ventricular level
Normal
attached to the base of the anterior leaflet of the mitral valve dorsally and interiorly to the semilunar valve (pulmonary valve in this case) (Fig. 1, follow dashed line encircling the patch). The suturing was thus carried deeply into the heart to the left wall of the outflow portion of the left ventricle. The suturing then followed the annulus of the posterior semilunar valve (pulmonary valve) around its left margin and anteriorly onto the fibrous or muscular tissue which separated the posterior (pulmonary) and anterior (aortic)
The Journal of Thoracic and Cardiovascular Surgery
4 3 2 McGoon
Anterior wall of right ventricle Lateral ,--^;.T-J:-^ wall J.-' ' """^i^ Aortic valve
1
^
V-_
Crista Pulmonar annulus
'
*V= Pulmonary v a l v e -
SB' '; V Anterior leaflet of_ tricuspid valve
B.| r IN
J
-_ i Ventricular septum
~>Anterior leaflet of 1 1 mitral 1 valve ^Rim of VSD
Fig. 1. Anatomy of transposition of the great arteries associated with large basilar ventricular septal defect. Line and sites of attachment of knitted Teflon patch, and its preferred shape, are shown. valves. Thus the patch now was being attached from left to right between the semilunar valves. When the suturing reached the right extremity of the ridge of tissue between the semilunar valves, the patch was next attached to the right wall of the outflow tract of the right ventricle along a line that extended to the right extremity of the ventriculotomy (Fig. 2, middle). This long suture line was terminated. Suturing was next resumed along the ventricular septum, beginning now where the attachment had been completed near the papillary muscle of the conus and continuing along the caudal margin of the septal defect and the left anterior aspect of the right ventricle until the left extremity of the ventriculotomy was reached (Fig. 2, middle). The final step was the attachment of the anterior margin of the patch between the lips of the ventriculotomy, incorporating the patch in the suture line used to close the ventriculotomy. Perfusion lasted 102 minutes, and the ascending aorta had been cross-clamped on five occasions, lasting from 4 to 17 minutes each and totalling 61 minutes. Between two of the periods of aortic cross-clamping, the secundum atrial septal defect had been closed by direct suture, via a right atriotomy. After the operation, respiratory distress re-
quired maintenance of assisted ventilation via the endotracheal tube for 30 hours. The hemodynamic status was satisfactory, but digitalis was administered. The recovery was uneventful, and the patient was dismissed from the hospital 11 days after operation. He returned 3 months later at our request for postoperative cardiac catheterization. In the interim, his preoperative symptoms had not recurred, he was normally active, and he had gained 6 pounds. A Grade 3 systolic murmur was present along the right sternal border. The catheterization showed correction of the defects (Tables I and II), save for hemodynamically significant residual subpulmonic stenosis. The angiocardiogram suggested that the repair was satisfactory; the child has remained clinically well 2Vi years after operation. CASE 2. A similar though unsuccessful operation was performed in February, 1971. The patient was 11 years old and had a patent ductus and not an atrial septal defect. There was no pulmonary stenosis, but in other respects there was a striking similarity with the first patient. The technique of repair was similar, except that there was more difficulty in avoiding bulging of the patch into the subpulmonic flow pathway. (The shape of the patch in Figs. 1 and 2 had not yet been
Volume 64
Intraventricular repair of TGA
Number 3
433
September, 1972
Pulmonary valve Aortic valve
Fig. 2. Left, Initial attachment of patch is same as for any posterior high ventricular septal defect. Middle and right, Subsequent steps in attachment of patch (see text for description). developed in the laboratory.7) Ventricular systolic pressures were equal after repair, at 85 mm. Hg, and a gradient of 25 mm. Hg existed between the right ventricle and the pulmonary artery. The patient died after a difficult 48 hour period that was characterized by intermittent low cardiac output. At autopsy, the left ventricular outflow tract was adequate (1 cm. in diameter), but the right ventricular outflow tract had narrowed to a diameter of 7 mm. Death was believed due to a combination of subpulmonic stenosis and pulmonary vascular obstructive disease.
Comment The concept of intraventricular repair of transposition of the great arteries, as reported herein, undoubtedly evolved as a result of stepwise successful correction of increasingly severe degrees of transposition: first the usual form of origin of both great arteries from the right ventricle, 8 - 9 then origin of both great vessels from the right ventricle associated with transposition of the great arteries and posterior ventricular
septal defect (Taussig-Bing variant 10 ), and now transposition of the great arteries with a large basal ventricular septal defect. Should late follow-up of patients who have undergone intra-atrial transposition of venous return for transposition of the great arteries show a significant incidence of tricuspid valvular insufficiency or right ventricular failure, there may be reason to explore the application of the presently reported technique. It is possible that, in patients with transposition of the great arteries who have only a posteriorly located ventricular septal defect or even no ventricular septal defect, a large ventricular septal defect of the type encountered in our patient could be created. Summary Intra-atrial transposition of venous return allows functional but not anatomic correction of transposition of the great arteries.
The Journal of
4 34
McGoon
Thoracic and Cardiovascular Surgery
A more nearly anatomic correction, performed within the ventricles, is described. The method involves replacement of the basal portion of the ventricular septum with a prosthetic septum in such a way that the reconstructed septum has a spiral configuration. The outflow of the left ventricle thus ends in the aorta and that of the right ventricle in the pulmonary artery. The first of two such operations has provided clinical success during a follow-up period of 2Vi years, although a moderate gradient exists between the right ventricle and the pulmonary artery. REFERENCES 1 McGoon, D. C : Surgery for Transposition of the Great Arteries (Editorial), Circulation. In press. 2 Albert, H. M.: Surgical Correction of Transposition of the Great Vessels, Surg. Forum 5: 74, 1955. 3 Merendino, K. A., Jesseph, J. E., Herron, P. W., Thomas, G. I., and Vetto, R. R.: Interatrial Venous Transposition: A One-Stage Intracardiac Operation for the Conversion of
Complete Transposition of the Aorta and Pulmonary Artery to Corrected Transposition: Theory and Clinical Experience, Surgery 42: 898, 1957. 4 Senning, A.: Surgical Correction of Transposition of the Great Vessels, Surgery 45: 966, 1959. 5 Shumacker, H. B, Jr.: A New Operation for Transposition of the Great Vessels, Surgery 50: 773, 1961. 6 Mustard, W. T., Keith, J. D., Trusler, G. A., Fowler, R., and Kidd, L.: The Surgical Management of Transposition of the Great Vessels, J. THORAC. CARDIOVASC. SURG. 48: 953,
1964.
7 Puga, F., and McGoon, D. C : Experimental Correction of Transposition of the Great Arteries. Unpublished data. 8 McGoon, D. C : Origin of Both Great Vessels From the Right Ventricle, Surg. Clin. North Am. 41: 1113, 1961. 9 Kirklin, J. W., Harp, R. A., and McGoon, D. C : Surgical Treatment of Origin of Both Vessels From the Right Ventricle, Including Cases of Pulmonary Stenosis, J. THORAC. CARDIOVASC. SURG. 48: 1026,
1964.
10 Patrick, D. L., and McGoon, D. C : An Operation for Double-Outlet Right Ventricle With Transposition of the Great Arteries, J. Cardiovasc. Surg. (Torino) 9: 537, 1968.