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Congenital diverticulum of the right ventricle
Case Rer>orts
Congenital Diverticulum of the Right Ventricle Association with Pulmonary
JOHN B. CARTER, MD ROBERT A. VAN TASSEL, JAMES H. MOLLER, MD KURT AMPLATZ, MD JESSE E. EDWARDS, MD St. Paul
and
Minneapolis,
MD
Minnesota
From the Department of Pathology, the Charles T. Miller Hospital, St. Paul, Minn. and the Departments of Pathology, Medicine, Pediatrics and Radiology, the University of Minnesota, Minneapolis, Minn. This study was supported by Public Health Service Research Grant 5 ROl HE05694 and Research Training Grant 5 TO1 HE05570 from the National Heart and Lung Institute. Manuscript received June 26, 1970, accepted September 9, 1970. Address for reprints: John 6. Carter, MD, Department of Pathology, Charles T. Miller Hospital, 125 West College Ave., St. Paul, Minn. 55102.
478
Stenosis and Ventricular
Septal Defect
Two cases of congenital diverticulum of the right ventricle are presented. In each case, the diverticulum was demonstrated by angiocardiography (venous in one and selective in the other). In the single case with selective right ventriculograms, pulsation of paradoxical nature was evident in the diverticulum. Fibrosis of the wall of the diverticulum was present in this case. In the other case, the wall contained normal myocardial tissue. In this case, venous angiocardiography was not adequate to demonstrate pulsation. In both cases the clinical features were like those of tetralogy of Mot and the anatomic features like those of ventricular septal defect and pulmonary stenosis. One case was typical anatomically for tetralogy of Fallot; the other was classified as double outlet right ventricle with pulmonary stenosis.
Congenital diverticula of the cardiac ventricles have been reported as arising either from the left ventricle or, rarely, from both ventric1es.l Such anomalies may occur as isolated lesions or as part of a syndrome including midline thoracic and abdominal defects2 and a defect of the diaphragm.3 According to Cumming4 a diverticulum arising from the right ventricle alone is very rare. He reported the single case. known to him. The prominence, which was walled by muscle, involved the right ventricular apex in a 9 year old boy with an atria1 septal defect. In the combined pathologic collections of the University of Minnesota and the Cardiovascular Registry of the Charles T. Miller Hospi8tal,there are 2 ‘examples of a diverticulum involving the lateral aspect of the base of the right ventricle. One case was associated with ,the classic features of tetralogy of Fallot. In the second case, the associated anatomic characteristics were those of origin of both great vessels from the right ventricle with infundibular and pulmonary valvular stenosis. The rarity of right ventricular diverticulum prompts us to report these 2 cases with emphasis upon the anatomic features. Antemortem angiocardiographic studies will be correlated with the anatomic findings. In each ‘case, the clinical picture was that of tetralogy of Fall& with cyanosis. Case 1 was from an infant who died at 2 months of age. Cardiac surgery had not been attempted. Case 2 involved a 4 year old girl in whom the classic anatomic features of tetralogy of Fallot were corrected operatively. In this case, the right ventricular diverticulum had been identified angiocardiographitally and was partially resected at the time of operation. Death ensued in the early postoperative period. In each case, the electrocardiogram was characteristic of that frequently present in Patients with tetralogy of Fallot.
The American Journal of CARDIOLOGY
CONGENITAL
DIVERTICULUM
OF RIGHT VENTRICLE
Figure 1. Case K. Origin of both great vessels from right ventricle with pulmonary stenosis. a, exterior of heart viewed from in front. The anterior aspect of the heart is occupied in part by the left ventricle (L.V.), the main portion of the right ventricle (R.V.) and the diverticulum (Div.) of the right ventricle. The latter lies inferior to the right atrial appendage. The right coronary artery (R.C.) courses between the diverticulum, above, and the main body of the right ventricle, below. In keeping with the presence of pulmonary stenosis, the pulmonary trunk (P.T.) is narrower than the aorta (A.). b, sagittal section of heart exposing the posterior aspect of the ventricular chambers and the aorta. (The infundibulum and pulmonary trunk were in the anterior portion of the specimen and do not appear in this illustration.) The aorta arises from the right ventricle near a subjacent ventricular septal defect (D.). The aortic and mitral valves (M.V.), although near each other, do not possess continuity. The diverticulum of the right ventricle shows a wide mouth lined by smooth endocardium. The tricuspid valve (T.V.) lies at a more posterior level than the ostium of the diverticulum.
Pathologic Features Case 1: Externally, the heart showed normally related great vessels and a narrow pulmonary trunk (Fig. 1). The right ventricle appeared to be of normal size but showed a prominent bulge extending from the lateral basal aspect of the chamber. The prominence lay inferior to the right atria1 appendage. From the outside, the space of the bulge appeared to occupy about three-fifths of that occupied by the right ventricle. The right coronary artery pursued an abnormal course. Instead of occupying the right atrioventricular sulcus, it lay in a groove between the prominence and the body of the right ventricle. The aorta arose from the right ventricle immediately above and to the right of a basal ventricular septal defect. A narrow infundibular channel led from the cavity of the right ventricle to the pulmonary trunk. The pulmonary valve was bicuspid and stenotic. Although, in general, the anatomic features resembled those of tetralogy of Fallot (with “extreme dextroposition”), lack of continuity between the mitral and aortic valves dictated an anatomic diagnosis of origin of both great vessels from the right ventricle with pulmonary stenosis (Fig. lb). Arising from the base of the right ventricle anterior to the tricuspid orifice was a large muscular-walled outpouching or diverticulum. The cavity of the diverticulum measured 1.7 cm in width and 1.3 cm in height. The mouth of the diverticulum was lined by smooth endocardium and measured 1.3 cm in diameter. It lay between a broad and flattened peripheral part of the parietal branch of the crista supraventricularis and a muscular protrusion arising from the lateral wall of the right ventricle. The interior aspect of the diver-
VOLUME 28, OCTOBER 1971
ticulum was highly trabeculated. The wall measured 0.4 cm in thickness, being equal in thickness to the wall of the main body of the right and left ventricles. Histologically, the wall of the diverticulum and of the right ventricle each showed normal myocardium with neither fibrosis nor endocardial change. The left-sided chambers and valves, as well as the right atrium and tricuspid valve, were normal. The foramen ovale showed valvular competent patency. The aortic arch was left-sided, and the ductus arteriosus was represented by a ligament. Case 2: The heart showed findings typical for the early stage after corrective operation for tetralogy of Fallot. A recent suture line was present at the lateral aspect of the base of the right ventricle which represented the site of resection of a diverticulum identified at operation. Examination of the interior of the right ventricle revealed that part of the diverticulum was still present (Fig. 2 and 3). Included in the residual material was the mouth of the diverticulum, which measured 1.0 cm in diameter. This was lined by smooth, endocardial tissue and walled by muscle. The diverticulum arose at the junction of the basal aspects of the anterior and lateral walls of ‘the right ventricle. The residual part of the main body of the diverticulum was distorted by the process of resection and repair, resulting in a tubular structure measuring about 2 by 1 cm with a thick, fibrous endocardium. In contrast to Case 1, the right coronary artery pursued a normal course in the right atrioventricular sulcus. Histologic examination of the wall of the diverticulum revealed endocardial fibroelastosis and myocardial atrophy with extensive fibrosis.
479
CARTER
ET AL.
Figure 2. Case 2. Tetralogy of Fallot. The perspective is similar to that in Figure lb. The aorta (A.) arises from both ventricles above a ventricular septal defect. The divetticulum (Div.) of the right ventricle (R.V.) is distorted by virtue of subtotal surgical resection. The endocardium of the diverticulum is thickly fibrous. The prosthetic patch surgically placed to close the communication between the right ventricle and the aorta is above point of arrow. L.V. = left ventricle.
Radiologic Observations In each case, thoracic roentgenograms were considered typical of tetralogy of Fallot except that a prominence occurred in the region normally occupied by the right atrium (Fig. 4). Retrospective study sug-, gests that, in each case, the prominence represented
Case 2. Diagrammatic portrayal of the anatomic Figure 3. situation before surgical intervention showing a diverticulum (Div.) of the right ventricle. Features of the tetralogy of Fallot are also present. I.V.C. = inferior vena cava; L.A. = left atrium; R.A. = right atrium; S.V.C. = superior vena cava. Other abbreviations as in Figure 1.
the right ventricular diverticulum. Angiocardiograms had been obtained in each case. Case 1: Venous angiocardiograms showed subdivision of the right ventricle into 2 segments. In the frontal view, the main body of the right ventricle was observed to fill early and to be the most opaque area in the mid-portion of the cardiac shadow (Fig. 5a). The diverticulum was not opacified at this stage but
Figure 4. Frontal views of roentgenograms of thorax in Case 1 (a) and in Case 2 (b). In each, there is prominence of the right margin of the heart. In Case 1, this was interpreted as part of cardiomegaly and, in Case 2, as that of a prominent right atrium. In each case, the prominence may portray the position of the diverticulum of the right ventricle.
480
The
American
Journal
of
CARDIOLOGY
CONGENITAL
DIVERTICULUM
OF RIGHT VENTRICLE
Figure 5. Case 1. Forward angiocardiograms. a, frontal view shows early filling of the right atrial appendage (R.A.A.), right ventricle (R.V.), aorta (A.) and pulmonary trunk (P.T.). Filling of the diverticulum (Div.) is delayed. The left ventricle (L.V.) is partially filled through a ventricular septal defect. View is comparable to that of gross specimen shown from this case in Figure lb. b, lateral view shows the divetticulum separated from the main body of the right ventricle by the radiolucent shadow of the muscle bundle. The less opaque left ventricle is also opacified.
became opaque later in the sequence. The left ventricle showed partial filling through the ventricular septal defect. Lateral views showed the diverticulum as the most anterior structure of the heart (Fig. 5b). The muscular bundle separating the diverticulum from the opaque main body of the right ventricle appeared as a lucent band between the main body of the right ventricle and its diverticulum. Case 2: Selective right and left ventriculograms had been obtained. The right ventriculogram showed,
in addition to findings typical for tetralogy of Fallot, a diverticulum at its base. The latter structure, which was clearly defined in the lateral view (Fig. 6a), was overshadowed by the aorta in frontal view (Fig. 6b). The left ventriculogram showed opacification of both ventricles. In lateral views, the right ventricular diverticulum was clearly visible protruding upward from the base of the right ventricle. During ventricular systole the diverticulum was larger than during diastole, although it remained opacified throughout the cardiac cycle (Fig. ‘7).
Figure 6. Case 2. Selective right ventriculograms. a, frontal view. The aorta (A.) and the left ventricle are opacified. The pulmonary trunk (P.T.) is narrow. The shadow of the diverticulum is superimposed upon that of the aorta and is not readily identifiable. b, in lateral view, features typical for the tetralogy of Fallot are apparent and, in addition, the diverticulum (Div.) projecting upward from the base of the right ventricle (R.V.) is readily apparent. A. = aorta; L.V. = left ventricle.
VOLUME
28, OCTOBER
1971
481
CARTER ET AL.
Figure 7. Case 2. Left ventriculograms in lateral views in diastolic (a) and in systolic (b) phases. In each, both ventricles, as well as the right ventricular diverticulum and the aorta, are opacified. In the diastolic phase (a) the diverticulum is less wide than in the systolic phase (b), indicating paradoxical motion of the wall of the diverticulum.
Comment The 2 cases described were similar in that a diverticulum of the right ventricle was located at the right basal aspect of the chamber. In Case 1, angiographic studies were inadequate to determine whether the diverticulum contracted in concert with the rest of the right ventricle. Since the wall of the diverticulum was formed by normal myocardium as thick as that of the main body of the right ventricle, one is led to the assumption that the diverticulum contracted during systole. In Case 2, angiocardiographic studies showed paradoxical motion of the diverticulum during ventricular systole. The basis for this phenomenon is understandable, in view of the extensive fibrosis of the wall of the diverticulum. In spite of the presence of fibrosis of the wall in Case 2 and absence of this change in Case 1, we consider the structure to be a congenital anomaly in each instance. The basis for formation of the diverticulum is not clear; nevertheless, one recalls that the normal right ventricle develops as an
outpouching of the primitive ventricle. If an extra focus of growth were present in the portion that is to form the right ventricle, a diverticulum could develop, in a sense, as an accessory ventricle. Indications for surgery: Since the material is limited, one is constrained from making generalizations as to therapy. Nevertheless, at this stage in our knowledge, it seems reasonable that the decision to resect the diverticulum should depend upon angiocardiographic demonstration of its functional characteristics. If paradoxical motion were demonstrated, resection would be as reasonable a procedure in preventing ventricular failure as resection of acquired left ventricular aneurysms. If good systolic contraction were demonstrated, it could be reasonable not to disturb the particular type of diverticulum described. With regard to operative considerations, it is well to recall that, in our Case 1, the right coronary artery followed an abnormal course, lying between the diverticulum and the body of the right ventricle rather than in its normal course along the atrioventricular sulcus.
References 1. Skauinker S: Diverticulum of the left ventricle of the heart. Review of literature and report of successful removal of diverticulum. Arch Surg (Chicago) 63:629-634, 1951 2. Edgett JW, Nelson WP, Hall RJ, et al: Diverticulum of the heart. Part of the syndrome of congenital cardiac and midline thoracic and abdominal defects. Amer J Cardiol 24: 580-583, 1969
482
3.
4
Mulder DG. Crittenden IH. Adams FH: Comolete reoair of a syndrome of congenitaidefects involving the abdominal wall, sternum, diaphragm, pericardium, and heart; excision of left ventricular divetticulum. Ann Surg 151:113122, 1960 Cumming GR: Congenital diverticulum of the right ventricle. Amer J Cardiol 23:294-297, 1969
The Amerkan
Journal
of CARDIOLOGY
Congenital Diverticulum of the Right Ventricle Association with Pulmonary
JOHN B. CARTER, MD ROBERT A. VAN TASSEL, JAMES H. MOLLER, MD KURT AMPLATZ, MD JESSE E. EDWARDS, MD St. Paul
and
Minneapolis,
MD
Minnesota
From the Department of Pathology, the Charles T. Miller Hospital, St. Paul, Minn. and the Departments of Pathology, Medicine, Pediatrics and Radiology, the University of Minnesota, Minneapolis, Minn. This study was supported by Public Health Service Research Grant 5 ROl HE05694 and Research Training Grant 5 TO1 HE05570 from the National Heart and Lung Institute. Manuscript received June 26, 1970, accepted September 9, 1970. Address for reprints: John 6. Carter, MD, Department of Pathology, Charles T. Miller Hospital, 125 West College Ave., St. Paul, Minn. 55102.
478
Stenosis and Ventricular
Septal Defect
Two cases of congenital diverticulum of the right ventricle are presented. In each case, the diverticulum was demonstrated by angiocardiography (venous in one and selective in the other). In the single case with selective right ventriculograms, pulsation of paradoxical nature was evident in the diverticulum. Fibrosis of the wall of the diverticulum was present in this case. In the other case, the wall contained normal myocardial tissue. In this case, venous angiocardiography was not adequate to demonstrate pulsation. In both cases the clinical features were like those of tetralogy of Mot and the anatomic features like those of ventricular septal defect and pulmonary stenosis. One case was typical anatomically for tetralogy of Fallot; the other was classified as double outlet right ventricle with pulmonary stenosis.
Congenital diverticula of the cardiac ventricles have been reported as arising either from the left ventricle or, rarely, from both ventric1es.l Such anomalies may occur as isolated lesions or as part of a syndrome including midline thoracic and abdominal defects2 and a defect of the diaphragm.3 According to Cumming4 a diverticulum arising from the right ventricle alone is very rare. He reported the single case. known to him. The prominence, which was walled by muscle, involved the right ventricular apex in a 9 year old boy with an atria1 septal defect. In the combined pathologic collections of the University of Minnesota and the Cardiovascular Registry of the Charles T. Miller Hospi8tal,there are 2 ‘examples of a diverticulum involving the lateral aspect of the base of the right ventricle. One case was associated with ,the classic features of tetralogy of Fallot. In the second case, the associated anatomic characteristics were those of origin of both great vessels from the right ventricle with infundibular and pulmonary valvular stenosis. The rarity of right ventricular diverticulum prompts us to report these 2 cases with emphasis upon the anatomic features. Antemortem angiocardiographic studies will be correlated with the anatomic findings. In each ‘case, the clinical picture was that of tetralogy of Fall& with cyanosis. Case 1 was from an infant who died at 2 months of age. Cardiac surgery had not been attempted. Case 2 involved a 4 year old girl in whom the classic anatomic features of tetralogy of Fallot were corrected operatively. In this case, the right ventricular diverticulum had been identified angiocardiographitally and was partially resected at the time of operation. Death ensued in the early postoperative period. In each case, the electrocardiogram was characteristic of that frequently present in Patients with tetralogy of Fallot.
The American Journal of CARDIOLOGY
CONGENITAL
DIVERTICULUM
OF RIGHT VENTRICLE
Figure 1. Case K. Origin of both great vessels from right ventricle with pulmonary stenosis. a, exterior of heart viewed from in front. The anterior aspect of the heart is occupied in part by the left ventricle (L.V.), the main portion of the right ventricle (R.V.) and the diverticulum (Div.) of the right ventricle. The latter lies inferior to the right atrial appendage. The right coronary artery (R.C.) courses between the diverticulum, above, and the main body of the right ventricle, below. In keeping with the presence of pulmonary stenosis, the pulmonary trunk (P.T.) is narrower than the aorta (A.). b, sagittal section of heart exposing the posterior aspect of the ventricular chambers and the aorta. (The infundibulum and pulmonary trunk were in the anterior portion of the specimen and do not appear in this illustration.) The aorta arises from the right ventricle near a subjacent ventricular septal defect (D.). The aortic and mitral valves (M.V.), although near each other, do not possess continuity. The diverticulum of the right ventricle shows a wide mouth lined by smooth endocardium. The tricuspid valve (T.V.) lies at a more posterior level than the ostium of the diverticulum.
Pathologic Features Case 1: Externally, the heart showed normally related great vessels and a narrow pulmonary trunk (Fig. 1). The right ventricle appeared to be of normal size but showed a prominent bulge extending from the lateral basal aspect of the chamber. The prominence lay inferior to the right atria1 appendage. From the outside, the space of the bulge appeared to occupy about three-fifths of that occupied by the right ventricle. The right coronary artery pursued an abnormal course. Instead of occupying the right atrioventricular sulcus, it lay in a groove between the prominence and the body of the right ventricle. The aorta arose from the right ventricle immediately above and to the right of a basal ventricular septal defect. A narrow infundibular channel led from the cavity of the right ventricle to the pulmonary trunk. The pulmonary valve was bicuspid and stenotic. Although, in general, the anatomic features resembled those of tetralogy of Fallot (with “extreme dextroposition”), lack of continuity between the mitral and aortic valves dictated an anatomic diagnosis of origin of both great vessels from the right ventricle with pulmonary stenosis (Fig. lb). Arising from the base of the right ventricle anterior to the tricuspid orifice was a large muscular-walled outpouching or diverticulum. The cavity of the diverticulum measured 1.7 cm in width and 1.3 cm in height. The mouth of the diverticulum was lined by smooth endocardium and measured 1.3 cm in diameter. It lay between a broad and flattened peripheral part of the parietal branch of the crista supraventricularis and a muscular protrusion arising from the lateral wall of the right ventricle. The interior aspect of the diver-
VOLUME 28, OCTOBER 1971
ticulum was highly trabeculated. The wall measured 0.4 cm in thickness, being equal in thickness to the wall of the main body of the right and left ventricles. Histologically, the wall of the diverticulum and of the right ventricle each showed normal myocardium with neither fibrosis nor endocardial change. The left-sided chambers and valves, as well as the right atrium and tricuspid valve, were normal. The foramen ovale showed valvular competent patency. The aortic arch was left-sided, and the ductus arteriosus was represented by a ligament. Case 2: The heart showed findings typical for the early stage after corrective operation for tetralogy of Fallot. A recent suture line was present at the lateral aspect of the base of the right ventricle which represented the site of resection of a diverticulum identified at operation. Examination of the interior of the right ventricle revealed that part of the diverticulum was still present (Fig. 2 and 3). Included in the residual material was the mouth of the diverticulum, which measured 1.0 cm in diameter. This was lined by smooth, endocardial tissue and walled by muscle. The diverticulum arose at the junction of the basal aspects of the anterior and lateral walls of ‘the right ventricle. The residual part of the main body of the diverticulum was distorted by the process of resection and repair, resulting in a tubular structure measuring about 2 by 1 cm with a thick, fibrous endocardium. In contrast to Case 1, the right coronary artery pursued a normal course in the right atrioventricular sulcus. Histologic examination of the wall of the diverticulum revealed endocardial fibroelastosis and myocardial atrophy with extensive fibrosis.
479
CARTER
ET AL.
Figure 2. Case 2. Tetralogy of Fallot. The perspective is similar to that in Figure lb. The aorta (A.) arises from both ventricles above a ventricular septal defect. The divetticulum (Div.) of the right ventricle (R.V.) is distorted by virtue of subtotal surgical resection. The endocardium of the diverticulum is thickly fibrous. The prosthetic patch surgically placed to close the communication between the right ventricle and the aorta is above point of arrow. L.V. = left ventricle.
Radiologic Observations In each case, thoracic roentgenograms were considered typical of tetralogy of Fallot except that a prominence occurred in the region normally occupied by the right atrium (Fig. 4). Retrospective study sug-, gests that, in each case, the prominence represented
Case 2. Diagrammatic portrayal of the anatomic Figure 3. situation before surgical intervention showing a diverticulum (Div.) of the right ventricle. Features of the tetralogy of Fallot are also present. I.V.C. = inferior vena cava; L.A. = left atrium; R.A. = right atrium; S.V.C. = superior vena cava. Other abbreviations as in Figure 1.
the right ventricular diverticulum. Angiocardiograms had been obtained in each case. Case 1: Venous angiocardiograms showed subdivision of the right ventricle into 2 segments. In the frontal view, the main body of the right ventricle was observed to fill early and to be the most opaque area in the mid-portion of the cardiac shadow (Fig. 5a). The diverticulum was not opacified at this stage but
Figure 4. Frontal views of roentgenograms of thorax in Case 1 (a) and in Case 2 (b). In each, there is prominence of the right margin of the heart. In Case 1, this was interpreted as part of cardiomegaly and, in Case 2, as that of a prominent right atrium. In each case, the prominence may portray the position of the diverticulum of the right ventricle.
480
The
American
Journal
of
CARDIOLOGY
CONGENITAL
DIVERTICULUM
OF RIGHT VENTRICLE
Figure 5. Case 1. Forward angiocardiograms. a, frontal view shows early filling of the right atrial appendage (R.A.A.), right ventricle (R.V.), aorta (A.) and pulmonary trunk (P.T.). Filling of the diverticulum (Div.) is delayed. The left ventricle (L.V.) is partially filled through a ventricular septal defect. View is comparable to that of gross specimen shown from this case in Figure lb. b, lateral view shows the divetticulum separated from the main body of the right ventricle by the radiolucent shadow of the muscle bundle. The less opaque left ventricle is also opacified.
became opaque later in the sequence. The left ventricle showed partial filling through the ventricular septal defect. Lateral views showed the diverticulum as the most anterior structure of the heart (Fig. 5b). The muscular bundle separating the diverticulum from the opaque main body of the right ventricle appeared as a lucent band between the main body of the right ventricle and its diverticulum. Case 2: Selective right and left ventriculograms had been obtained. The right ventriculogram showed,
in addition to findings typical for tetralogy of Fallot, a diverticulum at its base. The latter structure, which was clearly defined in the lateral view (Fig. 6a), was overshadowed by the aorta in frontal view (Fig. 6b). The left ventriculogram showed opacification of both ventricles. In lateral views, the right ventricular diverticulum was clearly visible protruding upward from the base of the right ventricle. During ventricular systole the diverticulum was larger than during diastole, although it remained opacified throughout the cardiac cycle (Fig. ‘7).
Figure 6. Case 2. Selective right ventriculograms. a, frontal view. The aorta (A.) and the left ventricle are opacified. The pulmonary trunk (P.T.) is narrow. The shadow of the diverticulum is superimposed upon that of the aorta and is not readily identifiable. b, in lateral view, features typical for the tetralogy of Fallot are apparent and, in addition, the diverticulum (Div.) projecting upward from the base of the right ventricle (R.V.) is readily apparent. A. = aorta; L.V. = left ventricle.
VOLUME
28, OCTOBER
1971
481
CARTER ET AL.
Figure 7. Case 2. Left ventriculograms in lateral views in diastolic (a) and in systolic (b) phases. In each, both ventricles, as well as the right ventricular diverticulum and the aorta, are opacified. In the diastolic phase (a) the diverticulum is less wide than in the systolic phase (b), indicating paradoxical motion of the wall of the diverticulum.
Comment The 2 cases described were similar in that a diverticulum of the right ventricle was located at the right basal aspect of the chamber. In Case 1, angiographic studies were inadequate to determine whether the diverticulum contracted in concert with the rest of the right ventricle. Since the wall of the diverticulum was formed by normal myocardium as thick as that of the main body of the right ventricle, one is led to the assumption that the diverticulum contracted during systole. In Case 2, angiocardiographic studies showed paradoxical motion of the diverticulum during ventricular systole. The basis for this phenomenon is understandable, in view of the extensive fibrosis of the wall of the diverticulum. In spite of the presence of fibrosis of the wall in Case 2 and absence of this change in Case 1, we consider the structure to be a congenital anomaly in each instance. The basis for formation of the diverticulum is not clear; nevertheless, one recalls that the normal right ventricle develops as an
outpouching of the primitive ventricle. If an extra focus of growth were present in the portion that is to form the right ventricle, a diverticulum could develop, in a sense, as an accessory ventricle. Indications for surgery: Since the material is limited, one is constrained from making generalizations as to therapy. Nevertheless, at this stage in our knowledge, it seems reasonable that the decision to resect the diverticulum should depend upon angiocardiographic demonstration of its functional characteristics. If paradoxical motion were demonstrated, resection would be as reasonable a procedure in preventing ventricular failure as resection of acquired left ventricular aneurysms. If good systolic contraction were demonstrated, it could be reasonable not to disturb the particular type of diverticulum described. With regard to operative considerations, it is well to recall that, in our Case 1, the right coronary artery followed an abnormal course, lying between the diverticulum and the body of the right ventricle rather than in its normal course along the atrioventricular sulcus.
References 1. Skauinker S: Diverticulum of the left ventricle of the heart. Review of literature and report of successful removal of diverticulum. Arch Surg (Chicago) 63:629-634, 1951 2. Edgett JW, Nelson WP, Hall RJ, et al: Diverticulum of the heart. Part of the syndrome of congenital cardiac and midline thoracic and abdominal defects. Amer J Cardiol 24: 580-583, 1969
482
3.
4
Mulder DG. Crittenden IH. Adams FH: Comolete reoair of a syndrome of congenitaidefects involving the abdominal wall, sternum, diaphragm, pericardium, and heart; excision of left ventricular divetticulum. Ann Surg 151:113122, 1960 Cumming GR: Congenital diverticulum of the right ventricle. Amer J Cardiol 23:294-297, 1969
The Amerkan
Journal
of CARDIOLOGY