COR TRIATRIATUM: A DIAGNOSTIC SURGICAL ENIGMA

COR TRIATRIATUM: A DIAGNOSTIC SURGICAL ENIGMA

COR TRIATRIATUM: A D I A G N O S T I C SURGICAL E N I G M A Claude Grondin, M.D. (by invitation), invitation), Ray C. Anderson, (by invitation), Ar...

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COR TRIATRIATUM: A D I A G N O S T I C SURGICAL E N I G M A Claude Grondin, M.D. (by invitation), invitation),

Ray C. Anderson,

(by invitation),

Arnold S. Leonard, M.D.

M.D. (by invitation),

Jesse E. Edwards, M.D. (by invitation),

(by

Kurt A. Amplatz,

M.D.

and

Richard L. Varco, M.D., Minneapolis and St. Paul, Minn.

C

is a rare cardiac anomaly wherein the pulmonary veins enter an accessory chamber which, in turn, joins the left atrium through a nar­ row opening. This condition often presents a challenging diagnostic problem, especially in variants of the classical form. In the classical form, the simplicity of surgical correction makes prompt diagnosis of this anomaly imperative. The condition was first clearly described in 1868 by Church 1 and later classified by Loemer in 1949.2 In a recent review of the literature, Niwayama 3 reported the cases of 38 patients and noted five instances in which successful surgical repair had been accomplished. The first two reports of surgical correction of this condition appeared but a few weeks apart and were presented by Lewis4 and by Vineberg 5 and their respective associates. Since earlier reports from the University of Minnesota Hospitals, 4 ' 6 we have had the opportunity to operate upon 3 additional patients and, addi­ tionally, have encountered 2 non-surgical cases at necropsy. These cases serve to demonstrate that other anomalies of the pulmonary veins may be associated with cor triatriatum, and this association creates complicated diagnostic and therapeutic problems. Before entering into a consideration of the details in our cases, a descrip­ tion of cor triatriatum and its variants, together with its developmental anatomy, will be given. OR TRIATRIATUM

PATHOLOGIC AND DEVELOPMENTAL CONSIDERATIONS

In its simplest form, cor triatriatum is a clear-cut entity in which all the pulmonary veins join an accessory atrial chamber which lies posterior and suFrom the Departments of Surgery, Pediatrics, Radiology, and Pathology, University of Minnesota, Minneapolis, Minn., and the Department of Pathology, The Charles T. Miller Hospi­ tal, St. Paul, Minn. This study was supported by Research Grant No. HE-5694 of the National Heart Institute, U. S. Public Health Service. Read at the Forty-fourth Annual Meeting of The American Association for Thoracic Surgery, Montreal, Canada, April 27, 28, and 29, 1964.

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Left

Fig. 1.—Classic cor triatriatum as observed in necropsy of Case 2. a. Photograph of speci­ men. 6. Drawing from same perspective as a. The pulmonary veins join an accessory left atrial chamber which, in turn, communicates with the true left atrium (L.A.) through a stenotie opening. The mitral valve and left ventricle (L.V.) are normal.

perior to the left atrium. The accessory chamber, in turn, joins the left atrium through a narrow opening. The latter represents the stenotie focus in the chan­ nel leading from the pulmonary veins to the left side of the heart (Fig. 1). The secondary effects of stenosis in this pathway are similar to those of mitral ste­ nosis, that is, an elevation of pressure in all segments of the pulmonary vascular system and in the right ventricle. While classic cor triatriatum forms a clearly denned entity, there are varia­ tions from this state, and a review of the development of the pulmonary veins gives insight into the basis for those variations that occur.7 The lungs are derived from the alimentary canal which obtains its blood supply from the splanchnic plexus. Hence, the initial blood supply of the pul­ monary primordium is from this source. Morever, the primordium of the two lungs is one tissue mass and thus the blood supply of this primordium has one vascular unit. Therefore, in the fully developed state, a blood vessel, either artery or vein, from one lung may cross the midline and join a blood vessel of similar class from the other lung. The initial venous drainage of the pulmonary primordium is the same as that of the alimentary canal. Two classes of veins serve to receive blood from the developing lungs. These are, first, the parietal veins which form the cardi­ nal venous systems of the embryo and, second, the visceral veins of the abdomen. The latter collectively may be called the umbilico-vitelline system. At the earliest stage in development of the lungs, the drainage of blood is into these two sys­ tems and there is no direct connection between the developing pulmonary veins and the heart. A comparatively late structure to develop is the diverticulum,

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TRIATEIATUM

F i g . 2 . — D i a g r a m m a t i c p o r t r a y a l of s t a g e s in t h e n o r m a l d e v e l o p m e n t of t h e p u l m o n a r y veins. I n i t i a l l y , t h e blood s u p p l y of t h e developing l u n g s is t h e s p l a n c h n i c p l e x u s ( S P ) . T h e initial v e n o u s d r a i n a g e is to t h e c a r d i n a l ( C V ) a n d umbilico-vitelline s y s t e m ( U V ) of veins. Secondarily, a connection b e t w e e n t h e h e a r t a n d t h e s p l a n c h n i c v a s c u l a r s y s t e m is m a d e in t h e form of t h e c o m m o n p u l m o n a r y vein ( C P V ) . L a t e r , t h e c o n n e c t i o n s w i t h t h e c a r d i n a l a n d umbilico-vitelline v e i n s is lost a n d finally t h e c o m m o n p u l m o n a r y vein is a b s o r b e d into t h e left a t r i u m . ( D r a w i n g modified from L u c a s a n d a s s o c i a t e s : P e d i a t . Clin. N o r t h A m e r i c a 1 0 : 781, 1963.)

known as the common pulmonary vein, from that part of the sino-atrial region of the heart which later is to become the left atrium. The common pulmonary vein unites with the splanchnic plexus of the de­ veloping lung. That union provides, for the first time, a direct route for the return of blood from the developing lungs to the heart. Subsequently, the con­ nections between the splanchnic plexus, on one hand, and the two primitive venous systems—the cardinal and umbilico-vitelline—on the other, undergo atrophy and are lost as effective channels. Then the common pulmonary vein is absorbed, by differential growth, into the left atrial wall. This results in the definitive stage in which the four pul­ monary veins join the left atrium directly (Fig. 2).

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Fig-. 3.—Developmental basis for certain pulmonary venous anomalies, including cor triatriatum. a and b, Earliest and latest stages in normal development of pulmonary veins, as shown in Fig. 2. c, Cor triatriatum results from faulty incorporation of common pulmonary vein (C.P.V.) into wall of left atrium (L.A.). Dilatation of obstructed common pulmonary vein represents accessory left atrial chamber, d, Cor triatriatum and anomalous pulmonary venous connection. The latter process results from retention of connections between the splanchnic plexus and the cardinal venous system, e, Total anomalous pulmonary venous connection with atretic strand between pulmonary venous system and left atrium. The fundamental process is like that in d but with the exception that the connection between the common pulmonary vein and the left atrium is atretic.

Cor triatriatum appears to result from faulty absorption of the common pulmonary vein into the left atrium. The common pulmonary vein remains as an identifiable structure represented by the accessory atrial chamber of this anomaly (Fig. 3). Classically, in this malformation, no anomalous pulmonary venous connec­ tions are present. However, variants of the classic form exist and include those states in which an accessory atrial chamber communicates with the true left atrium in the usual manner of cor triatriatum, and, in addition, an anomalous vein runs from the accessory chamber to a systemic vein (Fig. 3, d). The exis­ tence of this latter condition is readily explained. Since the obstructive nature of the communication between the accessory atrial chamber and the true left atrium may be present at an early developmental stage, when some of the primitive connections between the splanchnic plexus and the cardinal and umbilico-vitelline veins are still present and functional, one or more of these primi­ tive venous channels remains as a patent vessel. Pathologically, the vein functioning as an "overflow" from the pulmonary to the systemic venous system is termed an anomalous pulmonary venous connection.

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Fig. 4.—Partial cor triatriatum and subtotal anomalous pulmonary venus connection as observed in Case 6. (From Shone et. al.: The American Journal of Cardiology 11:525, 1963. Published by The Reuben H. Donnelley Corporation.)

In another condition, all the pulmonary veins enter a chamber resembling the accessory atrial chamber of cor triatriatum. The latter chamber, however, fails to communicate with the left atrium except by an atretic strand. Prom the accessory chamber a vein runs to a derivative either of the cardinal or the umbilico-vitelline systems (Fig. 3, e). This condition is classified, not as cor tria­ triatum, but as total anomalous pulmonary venous connection. Developmentally, the latter condition is clearly related to cor triatriatum with anomalous pul­ monary venous connection. In cor triatriatum with anomalous pulmonary venous connection, an opening, however narrow, is present between the common pul­ monary vein and the left atrium. In the other variant, the junction of the common pulmonary vein and the left atrium is atretic and is represented by a strand between the two chambers. Still another variant of cor triatriatum with anomalous pulmonary venous connection is represented by the condition found in our Case 6. In these in­ stances, some of the pulmonary veins join an accessory left atrial chamber (cor triatriatum) while the remaining veins are connected with a systemic vein (Pig. 4). Our explanation for this complicated arrangement lies in understanding the developing pulmonary venous system, where more than one focus of obstruc­ tion can be present. At such points of obstruction, continuity of developing chan­ nels may be lost and primitive connections are retained as routes for the flow of pulmonary venous blood.

Fig. 5.—Cor triatriatum in which accessory atrial chamber (C.A.V.) joins right atrium (R.A.). The anomaly appears to result from a combination of the fundamental process which causes cor triatriatum and anomalous position of the atrial septum, a, Each of the pulmonary veins joins the accessory atrial chamber, b, Only the right pulmonary veins join the accessory atrial chamber (A.C.) while the left pulmonary veins join the left atrium (L.A.) normally. c, The condition in Case 5 in which situs inversus was present. The condition is a mirror image of that shown in b. The left pulmonary veins join the venous atrium (V.A.) while the veins of the right lung join the arterial atrium (A.A.) which is on the right side. A.V. = arterial ven­ tricle ; V.V. = venous ventricle.

Of additional interest are rare instances in which an accessory atrial cham­ ber receives all or some of the pulmonary veins but empties into the right, rather than the left, atrium (Pig. 5, a and b). This variant of cor triatriatum might be explained by two coexisting abnormalities. One would be a faulty position of the atrial septum, so that it would be farther toward the left than normal and hence to the left of the site of origin of the common pulmonary vein. This ab­ normality, depending upon its degree, could serve to direct all, or only the right, pulmonary veins into the right atrium. Secondly, the accessory chamber would develop as it does in classic cor triatriatum; that is, faulty incorporation of the common pulmonary vein into the atrial wall. An anomaly fundamentally of this type was encountered in one of our cases (Case 5) (Fig. 5, c). This patient also exhibited situs inversus, so that a mirror-image pattern of this variant was observed. As only part of the pulmonary venous system connected with the accessory chamber, the left, rather than the right, pulmonary veins (because of situs inversus) joined the accessory chamber. Yet another variation in cor triatriatum is that in which a defect lies be­ tween the right atrium, on one hand, and either the true left atrium or the accessory left atrial chamber, on the other (Fig. 6). If the opening lies be­ tween the two true atria, it may be considered a coincidental atrial septal de­ fect. If, however, the aperture is present between the right atrium and the accessory chamber, an unequivocal explanation for the opening is not forth­ coming. One possibility is that the opening, in fact, represents a form of anoma­ lous pulmonary venous connection to the right atrium. An alternate explanation is that the opening is a secondary rupture of the accessory chamber into the adjacent right atrium.

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Fig. 6.—Cor triatriatum in which a communication is present between the left side of the heart and the right atrium, a, Communication between accessory atrial chamber (C.P.V.) and the right atrium (R.A.). b, Communication between the true left atrium (L.A.) and the right atrium.

REPORT OF CASES ( T a b l e I ) CASE 1.-—(Case previously included in report of Lewis and associates.^) A 24-year-old man was admitted for investigation of a cardiac murmur and dyspnea. The electrocardiographie and roentgenographic findings were compatible with those found in atrial septal defect. Cardiac catheterization revealed only mild pulmonary hypertension. At operation, in 1955, the atrial septum was found to be intact. A bulging, tense chamber was observed over the posterior and superior aspects of the left atrium. Exploration of this revealed a stenosed, moderately calcined, communication between the tense accessory atrial chamber and the true left atrium. Under hypothermia and inflow stasis, the septum between the acces­ sory left atrial chamber and the true left atrium was excised. When last seen, in 1962, the patient was asymptomatic. CASE 2.—A 3-year-old girl was admitted to the hospital in a state of severe congestive. cardiac failure and died 3 days later. At necropsy, a classical example of cor triatriatum was found in which the opening between the accessory left atrial chamber and the true left atrium measured only 1.5 mm. in diameter (see Fig. 1 ) . CASE 3.—(Case previously reported by Anderson and Varco. 6 ) A second 3-year-old child entered the hospital for evaluation of a cardiac murmur and moderately severe congestive heart failure. Roentgenographic study revealed moderate cardiomegaly and prominent vascular markings. The electrocardiogram indicated right ventricular hypertrophy. Cardiac catheteri­ zation showed severe pulmonary hypertension and marked elevation of the pulmonary arterial ' ' w e d g e ' ' pressure. Selective angiography demonstrated that the pulmonary veins entered the left atrium more medially and superiorly than usual. At operation, an accessory left atrial chamber with a 5 mm. opening into the left atrium was found. The opening between the two chambers was enlarged. Cardiac catheterization and electrocardiography, one year later, revealed a normal pulmonary arterial ' ' w e d g e ' ' pressure and lesser degree of right ventricular hypertension. CASE 4.—The fourth case was that of an 8-month-old infant who died 48 hours follow­ ing admission to the hospital for investigation of a cardiac murmur and convulsive disorders. A t necropsy, the following anomalies were present: cor triatriatum, incomplete variety of

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persistent common atrioventricular canal, partial anomalous pulmonary venous connection of the right upper pulmonary vein to the superior vena cava, and patent ductus arteriosus. CASE 5.—A 12-year-old girl with situs inversus was admitted to the hospital for evalua­ tion of a cardiac murmur. A " l e f t - t o - r i g h t " (arteriovenous) shunt into the venous atrium was indicated by the results of cardiac catheterization. At operation, the atrial septum was found to be intact. The left pulmonary veins joined an accessory chamber which, in turn, communicated with the venous atrium through a narrow opening (Fig. 5, c ) . Surgically, this ostium was diverted into the arterial atrium by creating an atrial septal defect and walling off the new channel from the venous atrium. Cardiac catheterization was done a year after operation and, apart from revealing persistent and unexplained elevated right ventricular pressure, the data were within normal limits. The patient was asymptomatic at that time. CASE 6.— (Case previously reported by Shone and associates. 8 ) The last case is that of a 19-month-old boy admitted to the hospital for progressive dyspnea one year subsequent to an admission in which coarctation of the aorta was corrected surgically. During the second admission, the electrocardiogram revealed right ventricular hypertrophy, and cardiac cathe­ terization demonstrated a gradient of 18 mm. H g between the pulmonary arterial " w e d g e " and the left atrial pressures. A left-to-right shunt at the atrial level was also demonstrated. The late phase of a selective angiographic study revealed that pulmonary veins joined into a small accessory atrial chamber ( K g . 7 ) . Based on these findings, a preoperative diagnosis of cor triatriatum was made. At operation, the diagnosis was confirmed to the extent that a small accessory atrial chamber was found. I t communicated with the right atrium through a patent foramen ovale and with the left atrium through a very small opening. The latter opening was enlarged. Immediately after the operation, the child developed severe pulmonary edema and, in spite of temporary improvement, died 24 hours later. The necropsy (see Fig. 4) revealed that the right upper and one of the two lower pulmonary veins joined a small accessory left atrial chamber. The second right lower pul­ monary vein made two interesting connections. I t received a venous bridge from that right lower pulmonary vein which joined the accessory atrial chamber and, from it, a collateral channel crossed the midline to join the left upper pulmonary vein. The two left pulmonary veins became confluent and, from this confluence, a vein ascended to terminate in the left innominate vein. TABLE I.

SUMMARY OF THE

DATA

DATA OP AGE (YR.)

PRESSURE RA

RV

1

Classic CT

24

5

35/2

36/15

2

Classic CT

3

-

-

-

3

Classic CT

3 4

10/5 7/4

85/0 39/0

85/34 34/12

4

CT, PDA, ASD, APVC

8/12

-

-

-

5

Partial CT, dextrocardia

8 12

6

37/5 40/2

25/ 5 19/ 6

ANOMALY

NO.

|

MPA

|

PW

|

LA

35

Partial CT, APVC 1-7/12 65/0 90/30 34/28 10 ¥ eoarc. This summary includes data of cardiac catheterization in the 4 cases in which this study was Pressures in millimeters of mercury. Oxygen (O2) saturation in percentages. CT, cor triatriatum. L + pulmonary venous connection. RV, right ventricle. MPA, main pulmonary artery. PW, pulmonary heart failure. 6

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Fig. 7.—Late phase of right ventriculogram in Case 6 in which part of the pulmonary venous supply joined a small accessory left atrial chamber (arrows) while the remainder of the pulmonary venous termination was to the left innominate vein. Latter feature not evident in study and was responsible for an incomplete clinical diagnosis. Anatomic condition shown in Fig. 4.

IN THE 6 REPORTED C A S E S * CATHETERIZATION 0 2 SATURATION VC

64(8)

|

RA

73

1

RV

72

1

i MPA

RBA

76

95

1

W

REMARKS

Died prior to cardiac catheterization, 69(1) 63(8)

69 73





75(1)

79

79(1)

66

L + "W

64 78

65 73

100

~"

~

_

Died prior to cardiac catheterization

84

84

96

L + W

66

50

97

Died postop. of C H F

done. In Cases 3 and 5 the first readings were made preoperatively and the second postoperatively. W, living and well. PDA, patent ductus arteriosus. ASD, atrial septal defect. APVC, anomalous arterial wedge pressure. LA, left atrium. VC, vena cava. RBA, right brachial artery. CHF, congestive

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CLINICAL P I C T U R E AND DIAGNOSIS

The onset of clinical manifestations in cor triatriatum depend on the de­ gree of pulmonary venous obstruction. Symptoms may be experienced as early as the first few days of life, or may be delayed until childhood or adult life. Dyspnea, cyanosis, signs of congestive heart failure, and failure to thrive are among the clinical manifestations. When symptoms occur in infancy, death may occur at this time in life unless surgical correction is promptly instituted. In the older child, the first clue to diagnosis of cor triatriatum may be derived from the conventional thoracic roentgenogram in the form of right ventricular hypertrophy, prominent pulmonary arteries, and evidence of long standing pulmonary venous obstruction. In this age period, a discrepancy be­ tween the size of the left atrium and the pulmonary features of pulmonary venous obstruction is helpful in differentiating cor triatriatum from mitral stenosis. In the infant, however, there is usually no cardiomegaly. The pulmonary fields are likely to exhibit a peculiar picture of diffuse haziness related to dila­ tation of the pulmonary venous channels, a so-called ground-glass appearance. The combination of normal cardiac size and a reticular pattern in the lungs is strongly suggestive of pulmonary venous obstruction. This combination is, however, not specific for cor triatriatum, as other conditions which also cause pulmonary venous obstruction may yield similar clinical findings. These con­ ditions may be located either proximal or distal to the mitral orifice. Electro­ cardiograph^ patterns, however, may prove most helpful in differentiating cor triatriatum from certain other anatomic entities that share pulmonary venous obstruction with cor triatriatum. A normal electrocardiogram is usually present in pulmonary parenchymal disease in this younger age group, but is rare in instances of pulmonary venous obstruction. On the other hand, the absence of left ventricular hypertrophy in a child with congestive heart failure, in most instances, rules out aortic ste­ nosis, primary myocardial sclerosis, coarctation of the aorta, and other obstruc­ tive lesions distal to the mitral valve. There remains, therefore, those obstructive lesions proximal to the mitral valve, which demonstrate electrocardiographic and radiologic signs of hyper­ trophy of the right cardiac chambers. This group includes mitral stenosis or atresia, stenosis of the individual pulmonary veins,8 atresia of the common pul­ monary vein,9 total anomalous pulmonary venous connection,10 and cor triatria­ tum. A precise anatomic diagnosis of these entities is desirable and should be attempted since some are now amenable to surgical correction. Angiographic studies and cardiac catheterization are most informative in separating these conditions. In congenital mitral stenosis, evidence of a pressure gradient across the mitral valve, accompanied by delayed emptying of an enlarged left atrium, is usually diagnostic of this anomaly. In mitral atresia, the latter angiographic sign is absent, but, in a rare instance of this anomaly, opacification of a levoatrio-cardinal vein carrying the pulmonary venous blood to a systemic vein may be observed, as well as evidence of a right-to-left shunt at the ventricular level.

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The specific diagnosis of congenital stenosis of the individual pulmonary veins can be established only by the angiographic demonstration of constriction of one or more pulmonary veins at the veno-atrial junction. 8 Data of cardiac catheterization, in this anomaly, indicate elevation of the pulmonary arterial "wedge" pressure in conjunction with a normal left atrial pressure, features common also to cor triatriatum, atresia of the common pulmonary vein, and total anomalous venous return with high resistance to pulmonary venous flow. Atresia of the common pulmonary vein anatomically is characterized by the absence of a connection between the pulmonary veins, on one hand, and the cardiac chambers or a major systemic vein, on the other. Contrast medium injected into the pulmonary artery will fail, in the late phase, to opacify either the left atrium or an anomalous venous return. 9 In some forms of total anomalous pulmonary venous connection, obstruc­ tion to the pulmonary venous flow is not manifest, but, rather, overloading of the right cardiac chambers and pulmonary arteries is a feature. In other forms, particularly the subdiaphragmatic variety, 10 pulmonary venous obstruc­ tion is a prominent feature. A specific diagnosis of total anomalous pulmonary venous connection may be made angiocardiographically, particularly if the contrast material is injected into the pulmonary trunk. Such a study outlines the pathway of anomalous pulmonary venous flow. In cor triatriatum, cardiac catheterization usually does not reveal an intracardiac shunt, but, rather, demonstrates an elevated pulmonary arterial " w e d g e " pressure. If the left atrial pressure is obtained, this is found to be normal. This combination of findings does not, however, rule out stenosis of the individual pulmonary veins, but, rather, excludes congenital mitral stenosis. Selective angiography in triatrial heart may clinch the diagnosis by showing the accessory left atrial chamber. This is best seen on the late phase in the frontal view. In one of our cases, this small chamber was identified slightly medial and above the predicted site of the left atrium (see Fig. 5). Although rarely mentioned in the literature, cor triatriatum may be as­ sociated with partial anomalous venous return. This anomaly existed in 2 of our 6 cases and was of major functional significance in one. In essence, several conditions may be responsible for congestive heart failure in the young infant. A peculiar pattern of pulmonary venous congestion in the thoracic roentgenogram should draw the clinician's attention to the left side of the heart. Furthermore, when there are neither roentgenographic nor electrocardiographic signs of left ventricular hypertrophy, roentgenographic signs of pulmonary venous obstruction should suggest those anomalies which are either at or proximal to the mitral valve. Cardiac catheterization may be of considerable value in differentiating the various possibilities. Indeed, a rightto-left shunt is usually detectable in atresia of the common pulmonary vein and total anomalous pulmonary venous connection, whereas, a left-to-right shunt is most prevalent in atresia of the mitral valve and is seldom seen in cor tria­ triatum and stenosis of the individual pulmonary veins. A normal left atrial pressure in the presence of an elevated pulmonary arterial " w e d g e " pressure is

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suggestive of stenosis of the individual pulmonary veins, of total anomalous venous connection with high resistance to flow, and of cor triatriatum. Opacification of an enlarged left atrial chamber strongly suggests mitral stenosis, although in rare instances of cor triatriatum, the third accessory chamber may be mistaken for the true left atrium. Furthermore, stenosis of the individual pulmonary veins may, in some in­ stances, be visualized angiocardiographically, as can total anomalous venous connection. Failure to opacify the left atrium or any other route of pulmonary venous return is typical of atresia of the common pulmonary vein. On the other hand, opacification of the accessory left atrial chamber may at times be achieved in cor triatriatum. It is evident that an absolute diagnosis cannot be made clinically in each case of cor triatriatum. In some instances, the diagnosis is not established until the time of surgical exploration. SUMMARY

The rare entity, cor triatriatum, is readily amenable to surgical correction. Six cases of cor triatriatum have been presented, 4 of which were treated surgi­ cally. One patient died of cardiac failure postoperatively. In this instance, sub­ total anomalous pulmonary venous connection was overlooked both preoperatively and at operation. Catheterization studies in the 3 patients surviving operation demonstrated a tendency toward resolution of pulmonary hyperten­ sion. Some aspects of the embryologic development of the pulmonary veins have been reviewed in an attempt to understand better this anomaly and to correlate it with other congenital defects, such as atresia of the common pulmonary vein and anomalous pulmonary venous return. Early presumptive diagnosis of this uncommon congenital defect, especially in the large ntimber of infants who present with congestive heart failure, could lead to a prompt correction and increase salvage rather than termination as a pathologic curiosity. Consideration is given toward the clinical distinction of cor triatriatum from other anomalies which also cause pulmonary venous obstruction. REFERENCES

1. Church, W. S.: Congenital Malformation of the H e a r t : Abnormal Septum in the Left Auricle, Tr. Path. Soc. London 19: 188, 1868. 2. Loeffler, E . : Unusual Malformation of the Left Atrium: Pulmonary Sinus, Arch. Path. 48: 371, 1949. 3. Niwayama, G.: Cor triatriatum, Am. Heart J . 59: 291, 1960. 4. Lewis, F . J., Varco, R. L., Tauffic, M., and Niazi, A.: Direct Vision Repair of Triatrial Heart and Total Anomalous Pulmonary Venous Drainage, Surg. Gynec. & Obst. 102: 713, 1956. 5. Vineberg, A., and Glalloneto, O.: Report of a Successful Operation for Stenosis of the Common Pulmonary Vein (Cor Triatriatum), Canad. M. A. J . 74: 719, 1956. 6. Anderson, R. C , and Varco, R. L.: Cor Triatriatum: Successful Diagnosis and Surgical Correction in a Three Year Old Girl, Am. J . Cardiol. 7: 436, 1961. 7. Edwards, J . E . : Pathologic and Developmental Considerations in Anomalous Pulmonary Venous Connection, Proc. Staff Meet. Mayo Clin. 28: 441, 1953.

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8. Shone, J . D., Amplatz, K., Anderson, R. C , Adams, P., Jr., and Edwards, J . E . : Congeni­ tal Stenosis of Individual Pulmonary Veins, Circulation 26: 574, 1962. 9. Lucas, R. V., Jr., Woolfrey, B. F., Anderson, R. C , Lester, R. G., and Edwards, J . E . : Atresia of the Common Pulmonary Vein, Pediatrics 29: 729, 1962. 10. Lucas, R. V., Jr., Adams, P., Jr., Anderson, R. C , Varco, R. L., Edwards, J . E., and Lester, R. G.: Total Anomalous Pulmonary Venous Connection to the Portal Venous System: A Cause of Pulmonary Venous Obstruction, Am. J . Roentgenol. 86: 561, 1961. 11. Shone, J . D., Anderson, R. C , Amplatz, K., Varco, R. L., Leonard, A. S., and Edwards, J . E . : Pulmonary Venous Obstruction Prom Two Separate Coexistent Anomalies: Sub­ total Pulmonary Venous Connection to Cor Triatriatum and Subtotal Pulmonary Venous Connection to Left Innominate Vein, Am. J. Cardiol. 1 1 : 525, 1963. DISCUSSION

DR. A. ROBERT CORDELL, Winston-Salem, N. C — I would like to compliment Dr. Grondin for his very lucid discussion of cor triatriatum at least insofar as his English p a r t was concerned. The title of his abstract, which was " A Diagnostic Surgical E n i g m a , " im­ mediately brought to mind a difficult and, up to this point, almost insoluble patient with whom we have had some contact over the past 6 months. I would like to briefly present her case for his discussion, and perhaps some help from this audience. The case is that of a 7-year-old girl who was admitted to our hospital approximately 6 months ago because of recurrent upper respiratory infections. She was found to be in congestive heart failure, and she underwent right heart catheterization. [Slide] The chest x-ray films show some cardiomegaly and some pulmonary edema, and a rather prominent pulmonary artery along with some enlargement of the left atrium. [Slide] The electrocardiogram taken preoperatively shows some right ventricular hyper­ trophy, a very prominent P wave, and some so-called diphasic P-wave markings in V,. [Slide] Cardiac catheterization was carried out on the right side, and these findings, as you can see from the slide, demonstrate some elevation of pressures in the entire right side of the circulation. The capillary wedge pressure is not on this slide but was in the range of 30 mm. Hg. She underwent cineangiograms which were thought by our entire group to represent an extra septum in the atrium on the left side, and she was operated upon. [Slide] Pressures taken a t the time of operation on the left side revealed elevation of the left atrium, as you can see, and apparently there is no diastolic gradient between the atrium and the ventricle. There is no gradient across the left ventricular outflow tract. I t was difficult for us to believe, so we went ahead with some trepidation and opened the left atrium under bypass, and were amazed to find absolutely nothing wrong with the left atrium. Pulmonary veins entered normally. The septum was intact and in normal position. There was nothing wrong with the mitral valve or with the myocardium either in the atrium or ventricle. We repeated pressures and still could not explain these measurements. [Slide] Biopsy of the lung was taken and all it showed us was some interstitial fibrosis and some edema of the lung, which one might expect from the previous pulmonary hyper­ tension. This young lady survived our exploration and has been seen once since in the hospital, again with some pulmonary infection and some mild right congestive heart failure.