Pediatr Cardiol 13:85-88, 1992
Pediatric Cardiology 9 Springer-VerlagNewYorkInc. 1992
C o r T r i a t r i a t u m Sinistrum: O n e Institution's 2 8 - Y e a r E x p e r i e n c e Ali G h e i s s a r i ] J a m e s R. M a l m ] F r e d e r i c k O. B o w m a n , Jr., ~ a n d F r e d r i c k Z. B i e r m a n 2 Department of Surgery, Division of Thoracic and Cardiac Surgery, and 2 Department of Pediatrics, Division of Pediatric Cardiology, The Columbia Fresbyterian Medical Center, Columbia University College of Physicians & Surgeons, New York, New York, USA S U M M A R Y . Twelve patients with cor triatriatum sinistrum were treated over a 28-year period. Their ages ranged from 1 month to 7.5 years. Congestive heart failure was the most common presentation. Cardiac catheterization was performed on six of the 12 patients and a correct diagnosis of cor triatriatum was made on angiography in only four of the six. Of the remaining six patients, three were diagnosed as having cor triatriatum by echocardiography and three by autopsy. Echocardiography is now considered to be the diagnostic modality of choice in our institution. Seven patients were operated on and five died prior to diagnosis or treatment. Associated cardiac anomalies included persistent left superior vena cava, atrial septal defects, coarctation of the aorta, and total anomalous pulmonary venous drainage. A right atrial, transseptal approach to the common pulmonary chamber and excision of the left atrial membrane was found to be the treatment of choice and was used in six of the seven patients operated on. One patient died in the postoperative period. Thus, cor triatriatum sinistrum, a rare and potentially lethal congential cardiac anomaly, can be diagnosed by echocardiography and successfully treated surgically with a low operative mortality.
KEY WORDS: Cor triatriatum - - Congenital heart disease - - Pulmonary vascular disease - Left atrial membrane
Cor t r i a t r i a t u m s i n i s t r u m ( s u b d i v i d e d left atrium) is a n u n c o m m o n c o n g e n i t a l c a r d i a c a n o m a l y charact e r i z e d b y the a b n o r m a l d i v i s i o n of the left a t r i u m into t w o c h a m b e r s , a c o m m o n p u l m o n a r y c h a m b e r , a n d the t r u e left atrial c h a m b e r s e p a r a t e d b y a fibrom u s c u l a r m e m b r a n e in w h i c h o n e or m o r e restrictive ostia are p r e s e n t . T h e p u l m o n a r y v e i n s d r a i n into the p u l m o n a r y c h a m b e r , a n d the left atrial c h a m b e r c o n t a i n s the mitral w~lve a n d the atrial app e n d a g e . T h e d i a g n o s i s o f this a n o m a l y is a n indication for surgical i n t e r v e n t i o n , since 75% of unt r e a t e d p a t i e n t s die in i n f a n c y . W e r e p o r t h e r e i n o u r e x p e r i e n c e with c o r t r i a t r i a t u m s i n i s t r u m t h r o u g h a d e t a i l e d clinical a n d a n a t o m i c a n a l y s i s of 12 cases of this a n o m a l y .
Materials and Methods From 1960-1988, 12 patients with cor triatriatum sinistrum (seven female and five male) were seen at Columbia-Presbyterian Address offprint requests to: Dr. Ali Gheissari, St. Vincent Med-
ical Center, 201 South Alvarado Street, Suite #626, Los Angeles, CA 90057, USA.
Medical Center. Their ages at the time of diagnosis or death ranged from 1 month to 7.5 years, with a mean age of 11 months (Table 1). Five patients died prior to diagnosis or treatment, and seven patients were operated on, of which one died postoperatively. An autopsy was performed on all patients who died. The most common presenting signs and symptoms were those of congestive heart failure, such as respiratory distress, episodic cyanosis, and easy fatiguability (Table 2). On physical examination a systolic murmur was present in the majority of the patients. The electrocardiogram (ECG) was normal in two patients but revealed evidence of right axis deviation and right ventricular hypertrophy in the remaining 10. The chest x-ray revealed cardiomegaly and pulmonary venous congestion in all patients. Cardiac catheterization was performed on six of 12 patients (only two patients since 1979). Of the remaining six patients, three had echocardiographic diagnosis of cor triatriatum and an angiogram was felt to be unnecessary, and three died prior to cardiac catheterization and their diagnosis was made at autopsy. The hemodynamic data revealed pulmonary hypertension in most cases, but cor triatriatum was recognized by angiography in only four of the six patients. Associated congenital anomalies were present in nine of the 12 patients (Table 3), and included persistent left superior vena cava, atrial septal defects, coarctation of the aorta, and total anomalous pulmonary venous drainage. Surgical correction was performed in seven patients using moderate hypothermia and cardiopulmonary bypass. A right
86
Pediatric Cardiology Vol. 13, No. 2, 1992
Table 1. Summary of patients with cor triatriatum sinistrum
Table 3. Associated cardiovascular defects among 12 patients
with cor triatriatum sinistrum Number of patients: 12 Male: 5 Female: 7 Mean age at operation or death: I 1 months Surgical cases: 7 (1 death, 1963) Autopsy cases: 5 (4 prior to 1967)
Table 2, Presenting signs and symptoms in 12 patients with cot
triatriatum sinistrum Signs or symptoms
No. of patients
Easy fatiguability Episodic cyanosis Dyspnea & tachypnea Near syncope Systolic murmur Failure to thrive Pneumonia
5 6 10 1 7 4 2
atrial approach was chosen in all but one child. After entering the right atrium through an oblique atriotomy incision, the atrial septurn was incised at the level of the foramen ovale, or, when present, the atrial septa[ defect was enlarged. The common pup monary chamber was identified by the location of the pulmonary vein orifices above the subdividing membrane. The left atrial membrane was incised by first enlarging its orifice toward the atrial appendage and then excising as much of it as possible without injury to the mitral valve or the posterior wall of the left atrium. A complete excision of the membrane was not necessary. The atrial septum was then repaired primarily or patched with Dacron or pericardium. An approach through the posterior aspect of the common pulmonary chamber was used in one older child in whom a large common pulmonary chamber extending to the right side of the heart was present with no other associated anomalies. There was one postoperative death. This occurred in a 3-year-old child with a sudden cardiac arrest 3 h postoperatively. An autopsy was performed which revealed a complete repair and did not clarify the cause of the arrest. In the other patients, postoperative care typically required ventilatory support and the use of inotropic agents for a short period of time. Recovery was usually rapid and without complications.
Discussion
C o r triatriatum sinistrum (subdivided left atrium) is a rare congenital a n o m a l y w h i c h was first described in 1868 b y C h u r c h [2]. This a n o m a l y consists o f an a b n o r m a l f i b r o m u s c u l a r m e m b r a n e which divides the left atrium into t w o c h a m b e r s . T h e right-sided, posterior, superior, and a n o m a l o u s c h a m b e r receives the p u l m o n a r y veins. A n t e r i o r and inferior to it is the true left atrial c h a m b e r w h i c h contains the left atrial a p p e n d a g e and empties into the left ventri-
Associated defects
No. of patients
Left superior vena cava Primum ASD Coarctation of aorta AV canal Secundum ASD Single ventricle, TAPVD
3 2 2 1 1 I
ASD, atrial septal defect; AV, atrioventricular; TAPVD, total anomalous pulmonary venous drainage.
cle t h r o u g h the mitral valve. T h e two c h a m b e r s c o m m u n i c a t e with e a c h o t h e r t h r o u g h one or several restrictive fenestrations in the m e m b r a n e . A n atrial septal defect or patent f o r a m e n ovale is present in 7 0 - 8 0 % o f cases (Fig. 1) with an intact atrial s e p t u m in the r e m a i n d e r [6, 10]. This atrial septal d e f e c t can c o n n e c t the right atrium with the p r o x i m a l p u l m o n a r y v e n o u s c h a m b e r and can physiologically simulate total a n o m a l o u s p u l m o n a r y venous drainage with a left-to-right shunt at the atrial level, o r m a y be located b e t w e e n the true left atrial c h a m b e r and the right atrium. In this c a s e the pup m o n a r y veins m a y b e c o m e severely o b s t r u c t e d mimicking mitral stenosis or atresia [8]. Clinically, m o s t patients present with signs and s y m p t o m s o f c o n g e s t i v e heart failure. T h e severity o f these s y m p t o m s is usually d e p e n d e n t on the size o f the fenestration in the obstructing m e m b r a n e , the integrity o f the atrial s e p t u m , and the p r e s e n c e o f associated congenital defects. In general, it has b e e n noted that if the o p e n i n g in the m e m b r a n e is less than 3 m m in diameter, s y m p t o m s o c c u r in infancy. If the o p e n i n g is greater than 3 m m in diameter, the a n o m a l y m a y be u n d e t e c t e d for m o n t h s prior to the d e v e l o p m e n t o f s y m p t o m s [3]. T h e maj o r i t y o f o u r patients did h a v e early signs and s y m p t o m s o f c o n g e s t i v e heart failure with resultant fatiguability, d y s p n e a , and t a c h y p n e a . Episodic c y a n o s i s w a s also c o m m o n , p r e s e n t in 50% o f o u r patients. It is usually a sign o f central p u l m o n a r y v e n o u s o b s t r u c t i o n and an indication for e m e r g e n c y surgery. B e f o r e the a d v e n t o f e c h o c a r d i o g r a p h y , the diagnosis o f c o r triatriatum relied on c i n e a n g i o g r a p h y and h e m o d y n a m i c data f r o m cardiac catheterization. C a r d i a c c a t h e t e r i z a t i o n has often b e e n unsuccessful in establishing a c o r r e c t diagnosis. T h e m o s t c o m m o n p r o b l e m has b e e n discrimination o f c o r triatriatum f r o m total a n o m a l o u s p u l m o n a r y v e n o u s drainage or conditions causing p u l m o n a r y v e n o u s o b s t r u c t i o n , s u c h as p u l m o n a r y vein stenosis, su-
Gheissari et al.: Cor Triatriatum Sinistrum
87
RightpulmonaryveinsLeftpulmonaryveins | ~ Atrialseptum-~.~ ~ | ~ I I~ A 1~
~
~Obstructing membrane ~ll~k~"Leftatrial ~ appendage -Mitralvalve B
Fig. 1. Schematic depiction of cor triatriatum sinistrum with an intact atrial septum (A), an atrial septal defect located above the membrane (B), and an atrial septal defect located between the right and " t r u e " left atria (C).
Pig. 2. Apical four-chamber echocardiographic projection of cor triatriatum sinistrum at (A) end-systole with the mitral valve closed and (B) end-diastole with the mitral valve open in a patient with cor triatriatum sinistrum. The pulmonary venous chamber is separated from the anatomic left atrium by the obstructing membrane. Fig. 3. Postoperative apical four-chamber projection at (A) end-systole and (B) end-diastole. The pulmonary venous chamber is now continuous with the anatomic left atrmm. Anterior, A; posterior, B; left, L; right, R; left ventricular inflow, LVI; right ventricular inflow, RV1; left atrium, LA; right atrium, RA; pulmonary venous chamber, PVnC.
pramitral membrane, mitral stenosis, or double-outlet right atrium [7-9]. Anatomic definition of the pulmonary veins, left atrium, and mitral valve apparatus with cardiac ultrasound expedites the diagno-
sis of cor triatriatum and obviates the need for preoperative cardiac catheterization. Apical fourchamber and subxiphoid atrial long-axis projections can visualize the obstructing membrane (Figs. 2 and
88
3). The issue of anomalous pulmonary venous return is readily resolved by direct visualization of venous confluence with the common pulmonary chamber. Similarly, the anatomy of the mitral valve apparatus is displayed. The echocardiographic diagnosis of cor triatriatum focuses on the presence of the obstructing membrane and its relationship to the foramen ovale and the left atrial appendage [7]. Cardiac ultrasound also reveals secondary features of pulmonary venous obstruction, and quantitates the gradient across the membrane ostia. In our institution, all patients with cor triatriatum who were treated since 1979 had the correct diagnosis made by transthoracic echocardiography. Fifty percent of these patients, therefore, did not undergo cardiac catheterization and were successfully treated based on the echo diagnosis. There has recently been an increased use of transesophageal echocardiography in the diagnosis of congenital cardiac anomalies, including cor triatriatum. This technique appears to be superior to transthoracic echocardiography in its clarity and ability to provide more detailed imaging of cardiac structures [5]. Our experience with transesophageal echocardiography, however, is limited to adults and older children, and this modality was not used to diagnose cot triatriatum in this series of 12 patients. The mortality for untreated cases of cor triatriatum is as high as 70% in the first year of life. Surgical excision of the obstructing membrane through the right atrium is the treatment of choice for cor triatriatum [1]. This approach provides excellent visualization of the left atrial membrane allowing for its excision, exposure for repair of any coexisting atrial septal defect, and protection of the mitral valve. The operative mortality for repair of cot triatriatum is very low [1, 4] and should approach zero with further improvement in diagnostic and surgical techniques. Early, accurate identification of cot
Pediatric Cardiology Vol. 13, No. 2, 1992
triatriatum permits timely surgical intervention as emphasized by the results reported here. In summary, cor triatriatum sinistrum represents a rare but surgically treatable congenital cardiac defect. The diagnosis can be made by echocardiography. Successful surgical resection of the obstructing membrane and correction of any associated cardiac defects can result in lasting improvement of the patient's condition.
References 1. Arciniegas E, Farooki ZQ, Hakimi M, Perry BL, Green EW (1981) Surgical treatment of cor triatriatum. Ann Thorac Surg 32:571-577 2. Church WS (1868) Congenital malformations of the heart. Abnormal septum of the left auricle. Trans Pathol Soc London 19:188-199 3. Hammon JW Jr, Bender WH (1983) Major anomalies of pulmonary and thoracic systemic veins. In: Sabiston DC Jr, Spencer FC (ed) Surgery o f the chest, 4th edn. WB Saunders, Philadelphia, pp 1027-1050 4. Kirklin JW, Barratt-Boyes BG (1986) Cardiac surgery, 1st edn. Wiley & Sons, New York, pp 525-531 5. Ludomirsky A, Erickson C, Vick GW III, Cooley DA (1990) Transesophageal color flow Doppler evaluation of cor triatriatum in an adult. A m Heart J 120:451-455 6. Marin-Garcia J, Tandon R, Lucas RV Jr, Edwards JE (1975) Cor triatriatum. Study of 20 cases. Am J Cardiol 35:59-66 7. Ostman-Smith I, Silverman NH, Oldershaw P, Lincoln C, Shinebourne EA (1984) Cor triatriatum sinistrum: diagnostic features on cross sectional echocardiography. Br Heart J 51:211-219 8. Richardson JV, Doty DB, Siewers RD, Zuberbuhler JR (1981) Cor triatriatum (subdivided left atrium). J Thorac Cardiovasc Surg 81:232-238 9. Starc TJ, Bierman FZ, Bowman FO, Steeg CN, Wang NK, Krongrad E (1987) Pulmonary venous obstruction and atrioventricular canal anomalies: role of cor triatriatum and double outlet right atrium. J A m Coll Cardiol 9:830-833 10. Thelenius OG, Bharati S, Lev M (1976) Subdivided left atrium. An expanded concept of cor triatriatum sinistrum. A m J Cardio137:743-752
Pediatric Cardiology 9 Springer-VerlagNewYorkInc. 1992
C o r T r i a t r i a t u m Sinistrum: O n e Institution's 2 8 - Y e a r E x p e r i e n c e Ali G h e i s s a r i ] J a m e s R. M a l m ] F r e d e r i c k O. B o w m a n , Jr., ~ a n d F r e d r i c k Z. B i e r m a n 2 Department of Surgery, Division of Thoracic and Cardiac Surgery, and 2 Department of Pediatrics, Division of Pediatric Cardiology, The Columbia Fresbyterian Medical Center, Columbia University College of Physicians & Surgeons, New York, New York, USA S U M M A R Y . Twelve patients with cor triatriatum sinistrum were treated over a 28-year period. Their ages ranged from 1 month to 7.5 years. Congestive heart failure was the most common presentation. Cardiac catheterization was performed on six of the 12 patients and a correct diagnosis of cor triatriatum was made on angiography in only four of the six. Of the remaining six patients, three were diagnosed as having cor triatriatum by echocardiography and three by autopsy. Echocardiography is now considered to be the diagnostic modality of choice in our institution. Seven patients were operated on and five died prior to diagnosis or treatment. Associated cardiac anomalies included persistent left superior vena cava, atrial septal defects, coarctation of the aorta, and total anomalous pulmonary venous drainage. A right atrial, transseptal approach to the common pulmonary chamber and excision of the left atrial membrane was found to be the treatment of choice and was used in six of the seven patients operated on. One patient died in the postoperative period. Thus, cor triatriatum sinistrum, a rare and potentially lethal congential cardiac anomaly, can be diagnosed by echocardiography and successfully treated surgically with a low operative mortality.
KEY WORDS: Cor triatriatum - - Congenital heart disease - - Pulmonary vascular disease - Left atrial membrane
Cor t r i a t r i a t u m s i n i s t r u m ( s u b d i v i d e d left atrium) is a n u n c o m m o n c o n g e n i t a l c a r d i a c a n o m a l y charact e r i z e d b y the a b n o r m a l d i v i s i o n of the left a t r i u m into t w o c h a m b e r s , a c o m m o n p u l m o n a r y c h a m b e r , a n d the t r u e left atrial c h a m b e r s e p a r a t e d b y a fibrom u s c u l a r m e m b r a n e in w h i c h o n e or m o r e restrictive ostia are p r e s e n t . T h e p u l m o n a r y v e i n s d r a i n into the p u l m o n a r y c h a m b e r , a n d the left atrial c h a m b e r c o n t a i n s the mitral w~lve a n d the atrial app e n d a g e . T h e d i a g n o s i s o f this a n o m a l y is a n indication for surgical i n t e r v e n t i o n , since 75% of unt r e a t e d p a t i e n t s die in i n f a n c y . W e r e p o r t h e r e i n o u r e x p e r i e n c e with c o r t r i a t r i a t u m s i n i s t r u m t h r o u g h a d e t a i l e d clinical a n d a n a t o m i c a n a l y s i s of 12 cases of this a n o m a l y .
Materials and Methods From 1960-1988, 12 patients with cor triatriatum sinistrum (seven female and five male) were seen at Columbia-Presbyterian Address offprint requests to: Dr. Ali Gheissari, St. Vincent Med-
ical Center, 201 South Alvarado Street, Suite #626, Los Angeles, CA 90057, USA.
Medical Center. Their ages at the time of diagnosis or death ranged from 1 month to 7.5 years, with a mean age of 11 months (Table 1). Five patients died prior to diagnosis or treatment, and seven patients were operated on, of which one died postoperatively. An autopsy was performed on all patients who died. The most common presenting signs and symptoms were those of congestive heart failure, such as respiratory distress, episodic cyanosis, and easy fatiguability (Table 2). On physical examination a systolic murmur was present in the majority of the patients. The electrocardiogram (ECG) was normal in two patients but revealed evidence of right axis deviation and right ventricular hypertrophy in the remaining 10. The chest x-ray revealed cardiomegaly and pulmonary venous congestion in all patients. Cardiac catheterization was performed on six of 12 patients (only two patients since 1979). Of the remaining six patients, three had echocardiographic diagnosis of cor triatriatum and an angiogram was felt to be unnecessary, and three died prior to cardiac catheterization and their diagnosis was made at autopsy. The hemodynamic data revealed pulmonary hypertension in most cases, but cor triatriatum was recognized by angiography in only four of the six patients. Associated congenital anomalies were present in nine of the 12 patients (Table 3), and included persistent left superior vena cava, atrial septal defects, coarctation of the aorta, and total anomalous pulmonary venous drainage. Surgical correction was performed in seven patients using moderate hypothermia and cardiopulmonary bypass. A right
86
Pediatric Cardiology Vol. 13, No. 2, 1992
Table 1. Summary of patients with cor triatriatum sinistrum
Table 3. Associated cardiovascular defects among 12 patients
with cor triatriatum sinistrum Number of patients: 12 Male: 5 Female: 7 Mean age at operation or death: I 1 months Surgical cases: 7 (1 death, 1963) Autopsy cases: 5 (4 prior to 1967)
Table 2, Presenting signs and symptoms in 12 patients with cot
triatriatum sinistrum Signs or symptoms
No. of patients
Easy fatiguability Episodic cyanosis Dyspnea & tachypnea Near syncope Systolic murmur Failure to thrive Pneumonia
5 6 10 1 7 4 2
atrial approach was chosen in all but one child. After entering the right atrium through an oblique atriotomy incision, the atrial septurn was incised at the level of the foramen ovale, or, when present, the atrial septa[ defect was enlarged. The common pup monary chamber was identified by the location of the pulmonary vein orifices above the subdividing membrane. The left atrial membrane was incised by first enlarging its orifice toward the atrial appendage and then excising as much of it as possible without injury to the mitral valve or the posterior wall of the left atrium. A complete excision of the membrane was not necessary. The atrial septum was then repaired primarily or patched with Dacron or pericardium. An approach through the posterior aspect of the common pulmonary chamber was used in one older child in whom a large common pulmonary chamber extending to the right side of the heart was present with no other associated anomalies. There was one postoperative death. This occurred in a 3-year-old child with a sudden cardiac arrest 3 h postoperatively. An autopsy was performed which revealed a complete repair and did not clarify the cause of the arrest. In the other patients, postoperative care typically required ventilatory support and the use of inotropic agents for a short period of time. Recovery was usually rapid and without complications.
Discussion
C o r triatriatum sinistrum (subdivided left atrium) is a rare congenital a n o m a l y w h i c h was first described in 1868 b y C h u r c h [2]. This a n o m a l y consists o f an a b n o r m a l f i b r o m u s c u l a r m e m b r a n e which divides the left atrium into t w o c h a m b e r s . T h e right-sided, posterior, superior, and a n o m a l o u s c h a m b e r receives the p u l m o n a r y veins. A n t e r i o r and inferior to it is the true left atrial c h a m b e r w h i c h contains the left atrial a p p e n d a g e and empties into the left ventri-
Associated defects
No. of patients
Left superior vena cava Primum ASD Coarctation of aorta AV canal Secundum ASD Single ventricle, TAPVD
3 2 2 1 1 I
ASD, atrial septal defect; AV, atrioventricular; TAPVD, total anomalous pulmonary venous drainage.
cle t h r o u g h the mitral valve. T h e two c h a m b e r s c o m m u n i c a t e with e a c h o t h e r t h r o u g h one or several restrictive fenestrations in the m e m b r a n e . A n atrial septal defect or patent f o r a m e n ovale is present in 7 0 - 8 0 % o f cases (Fig. 1) with an intact atrial s e p t u m in the r e m a i n d e r [6, 10]. This atrial septal d e f e c t can c o n n e c t the right atrium with the p r o x i m a l p u l m o n a r y v e n o u s c h a m b e r and can physiologically simulate total a n o m a l o u s p u l m o n a r y venous drainage with a left-to-right shunt at the atrial level, o r m a y be located b e t w e e n the true left atrial c h a m b e r and the right atrium. In this c a s e the pup m o n a r y veins m a y b e c o m e severely o b s t r u c t e d mimicking mitral stenosis or atresia [8]. Clinically, m o s t patients present with signs and s y m p t o m s o f c o n g e s t i v e heart failure. T h e severity o f these s y m p t o m s is usually d e p e n d e n t on the size o f the fenestration in the obstructing m e m b r a n e , the integrity o f the atrial s e p t u m , and the p r e s e n c e o f associated congenital defects. In general, it has b e e n noted that if the o p e n i n g in the m e m b r a n e is less than 3 m m in diameter, s y m p t o m s o c c u r in infancy. If the o p e n i n g is greater than 3 m m in diameter, the a n o m a l y m a y be u n d e t e c t e d for m o n t h s prior to the d e v e l o p m e n t o f s y m p t o m s [3]. T h e maj o r i t y o f o u r patients did h a v e early signs and s y m p t o m s o f c o n g e s t i v e heart failure with resultant fatiguability, d y s p n e a , and t a c h y p n e a . Episodic c y a n o s i s w a s also c o m m o n , p r e s e n t in 50% o f o u r patients. It is usually a sign o f central p u l m o n a r y v e n o u s o b s t r u c t i o n and an indication for e m e r g e n c y surgery. B e f o r e the a d v e n t o f e c h o c a r d i o g r a p h y , the diagnosis o f c o r triatriatum relied on c i n e a n g i o g r a p h y and h e m o d y n a m i c data f r o m cardiac catheterization. C a r d i a c c a t h e t e r i z a t i o n has often b e e n unsuccessful in establishing a c o r r e c t diagnosis. T h e m o s t c o m m o n p r o b l e m has b e e n discrimination o f c o r triatriatum f r o m total a n o m a l o u s p u l m o n a r y v e n o u s drainage or conditions causing p u l m o n a r y v e n o u s o b s t r u c t i o n , s u c h as p u l m o n a r y vein stenosis, su-
Gheissari et al.: Cor Triatriatum Sinistrum
87
RightpulmonaryveinsLeftpulmonaryveins | ~ Atrialseptum-~.~ ~ | ~ I I~ A 1~
~
~Obstructing membrane ~ll~k~"Leftatrial ~ appendage -Mitralvalve B
Fig. 1. Schematic depiction of cor triatriatum sinistrum with an intact atrial septum (A), an atrial septal defect located above the membrane (B), and an atrial septal defect located between the right and " t r u e " left atria (C).
Pig. 2. Apical four-chamber echocardiographic projection of cor triatriatum sinistrum at (A) end-systole with the mitral valve closed and (B) end-diastole with the mitral valve open in a patient with cor triatriatum sinistrum. The pulmonary venous chamber is separated from the anatomic left atrium by the obstructing membrane. Fig. 3. Postoperative apical four-chamber projection at (A) end-systole and (B) end-diastole. The pulmonary venous chamber is now continuous with the anatomic left atrmm. Anterior, A; posterior, B; left, L; right, R; left ventricular inflow, LVI; right ventricular inflow, RV1; left atrium, LA; right atrium, RA; pulmonary venous chamber, PVnC.
pramitral membrane, mitral stenosis, or double-outlet right atrium [7-9]. Anatomic definition of the pulmonary veins, left atrium, and mitral valve apparatus with cardiac ultrasound expedites the diagno-
sis of cor triatriatum and obviates the need for preoperative cardiac catheterization. Apical fourchamber and subxiphoid atrial long-axis projections can visualize the obstructing membrane (Figs. 2 and
88
3). The issue of anomalous pulmonary venous return is readily resolved by direct visualization of venous confluence with the common pulmonary chamber. Similarly, the anatomy of the mitral valve apparatus is displayed. The echocardiographic diagnosis of cor triatriatum focuses on the presence of the obstructing membrane and its relationship to the foramen ovale and the left atrial appendage [7]. Cardiac ultrasound also reveals secondary features of pulmonary venous obstruction, and quantitates the gradient across the membrane ostia. In our institution, all patients with cor triatriatum who were treated since 1979 had the correct diagnosis made by transthoracic echocardiography. Fifty percent of these patients, therefore, did not undergo cardiac catheterization and were successfully treated based on the echo diagnosis. There has recently been an increased use of transesophageal echocardiography in the diagnosis of congenital cardiac anomalies, including cor triatriatum. This technique appears to be superior to transthoracic echocardiography in its clarity and ability to provide more detailed imaging of cardiac structures [5]. Our experience with transesophageal echocardiography, however, is limited to adults and older children, and this modality was not used to diagnose cot triatriatum in this series of 12 patients. The mortality for untreated cases of cor triatriatum is as high as 70% in the first year of life. Surgical excision of the obstructing membrane through the right atrium is the treatment of choice for cor triatriatum [1]. This approach provides excellent visualization of the left atrial membrane allowing for its excision, exposure for repair of any coexisting atrial septal defect, and protection of the mitral valve. The operative mortality for repair of cot triatriatum is very low [1, 4] and should approach zero with further improvement in diagnostic and surgical techniques. Early, accurate identification of cot
Pediatric Cardiology Vol. 13, No. 2, 1992
triatriatum permits timely surgical intervention as emphasized by the results reported here. In summary, cor triatriatum sinistrum represents a rare but surgically treatable congenital cardiac defect. The diagnosis can be made by echocardiography. Successful surgical resection of the obstructing membrane and correction of any associated cardiac defects can result in lasting improvement of the patient's condition.
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