Cor triatriatum dexter: antemortem diagnosis inan adult by cross sectional echocardiography

Anatole Trakhtenbroit, Pirzada Majid, Roxann Rokey

Br Heart J 1990;63:314-6

AbstractCor triatriatum dexter is a rare cardiacabnormality in which the right atrium issubdivided into two distinct chambers.This anomaly is generally attributed tothe persistence of the right sinus venosus

valve and it is frequently associated withsevere malformations ofother right heartstructures. The antemortem diagnosis ofthe membrane may be difficult and itspresence is often only established atnecropsy. ;n a woman of 56 with Ebstein'sanomaly the echocardiographic featuresof cor triatriatum dexter were examinedbefore and during cardiac catheterisa-tion. These investigations showed theposition of the membrane, that there wasno gradient between the two atrial cham-bers, and that there were perforations inthe centre of the membrane.

Cor triatriatum dexter or septation of the rightatrium to form a triatrial heart is a rare cardiaccondition caused by persistence of the embry-onic right valve of the sinus venosus."2 It iscommonly associated with important abnor-malities of other right heart structures. Onlythose with less severe involvement of the rightheart survive childhood.25 Usually the abnor-mal membrane is first discovered at necropsy,but recent reports suggest the diagnosis can beestablished antemortem by cross sectionalechocardiography.67 We describe a middleaged woman with echocardiographic findingsof cor triatriatum dexter and Ebstein'sanomaly. The anatomical location of the mem-brane and its physiological effects were estab-lished during a combined echocardiographicand cardiac catheterisation procedure and theseresults were confirmed at surgery.

Department ofInternal Medicine,Section of Cardiology,Baylor College ofMedicine, Houston,Texas, USAA TrakhtenbroitP MajidR RokeyCorrespondence toDr Roxann Rokey, TheMethodist Hospital, 6565Fannin, MS 941-A,Houston, Texas, 77030,USA.

Case reportA 56 year old woman was admitted for assess-

ment of frank cyanosis and clubbing of alldigits; these had been progressing slowly for 15years. She sought medical attention whendyspnoea on exertion and fatigue increased inthe two weeks before admission. She did nothave palpitation, orthopnoea, chest pain, or

oedematous feet.The jugular venous pressure was elevated

and a prominent CV wave of tricuspid regur-gitation was noted. A right ventricular impulsewas absent. The first heart sound was widelysplit and soft. The second heart sound was

narrowed but not paradoxically split and the

pulmonary component was soft. A right ven-tricular third heart sound was audible as was aII/VI early decrescendo systolic murmur overthe lower left sternal border which increasedwith inspiration. The liver was enlarged andpulsatile.The chest radiograph showed clear lung

fields and a small aortic root. The atria andright ventricle were enlarged. An electrocar-diogram showed normal sinus rhythm with anormal PR interval (200 ms), a right ventricularconduction defect without QRS prolongation,and a Q wave in VI and an S wave in V5 and V6.The left atrium was enlarged (fig 1).

CROSS SECTIONAL AND DOPPLERECHOCARDIOGRAMSThe situs of the atria and viscera was solituswith concordant atrioventricular and ventric-uloarterial connections. A membrane measur-

ing 7 cm in length divided the right atriumdiagonally into two chambers forming asuperomedial and inferolateral compartment.The membrane was very mobile during thecardiac cycle. During ventricular systole thecentral portion of the structure invertedtowards the roof of the right atrium and duringdiastole it everted towards the right ventricle(fig 2). The tricuspid valve leaflets were dis-placed downward into the right ventricular

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Cor triatriatum dexter in an adult

Figure 2 Apicalfour chamber echocardiogram of the heart during systole (left) and diastole (right). There was alarge mobile membrane dividing the right atrium into two chambers (large arrow). The membrane inverted toward theroof of the right atrium during systole and everted toward the right ventricle during diastole. Displacement of thetricuspid valve consistent with Ebstein's anomaly was also apparent (small arrows). IAS, interatrial septum; LA, leftatrium; LV, left ventricle; RA, right atrium; R V, right ventricle.

cavity. No significant obstruction of flow be-tween the two right atrial chambers was detec-ted on the Doppler echocardiographic examin-ation.On the basis of the physical examination and

echocardiographic findings, Ebstein's anomalyand cor triatriatum dexter with no significantobstruction to venous flow was diagnosed.

CARDIAC CATHETERISATION ANDANGIOCARDIOGRAPHYA combined cardiac catheterisation andechocardiographic procedure was performed.The right femoral artery, right femoral vein,and right internal jugular vein were cannu-lated. The venous catheters were advanced intothe superior and inferior venae cavae. Echocar-diography of agitated saline injected into theinferior vena cava showed opacification of thesuperomedial right atrial compartment andshunting of contrast across the mid-interatrialseptum into the left atrium. The contrast alsostreamed anterogradely into the lateral com-partment through multiple areas in the centralportion of the right atrial membrane. Whencontrast was injected in the superior vena cava,the inferolateral right atrial compartmentopacified before the superomedial compart-ment. Retrograde filling through the centralportion of the membrane resulted in completeopacification of the medial chamber within twocardiac cycles (fig 3).

The superior vena cava catheter entered theright ventricle through the lateral right atrialcompartment. The inferior vena cava catheterwas seen in the medial right atrial chamber andeasily passed through the mid-interatrial sep-tum into the left atrium. Despite repeatedattempts, neither catheter could be passedacross the right atrial membrane to enter theopposite atrial compartment. Though the cath-eters could not be placed through the mem-brane, as predicted by the earlier Dopplerexamination, no significant gradient betweenthe two compartments was detected. The rightventricular, pulmonary artery, and left atrialpressures were normal. A bidirectional shunt atthe mid-atrial level of 3-25 1/min (right to left)and 0-25 1/min (left to right) was calculatedfrom oximetric measurements and oxygen con-sumption.

Angiocardiography of the right heart showedthe displaced tricuspid valve leaflets, enlargedright atrium and right ventricle, and tricuspidregurgitation. Despite multiple projections,the membrane seen by echocardiography couldnot be shown during angiography. There wereno atherosclerotic lesions of the coronaryarteries.

FURTHER COURSESurgical intervention for tricuspid valve repairor replacement, closure of the atrial septaldefect, and resection of the membrane was

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Figure 3 Modified apicalfour chamber echocardiograms obtained during cardiac catheterisation after injection ofcontrast through the inferior vena cava (left) and the superior vena cava (right). Injection of contrast through theinferior vena cava showed the initial opacification of the superomedial right atrial chamber and streaming of contrastthrough the central portion of the membrane into the inferolateral chamber. Injection of contrast through the superiorvena cava showed opacification of the inferolateral right atrial chamber. LA, left atrium; LV, left ventricle; RA, rightatrium; R V, right ventricle.

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Trakhtenbroit, Majid, Rokey

recommended. At surgery, a large redundantfibrous membrane with multiple small cen-trally located fenestrations was found dividingthe right atrium into two compartments. Themembrane was attached inferiorly from thecristae terminalis to the inferior limbus of theinteratrial septum. Anteriorly, the membranewas connected to the right atrium in a similarcourse. The coronary sinus and inferior venacava were located to the left of the membraneand the superior vena cava to the right. Theseptal and lateral tricuspid valve leaflets wereadherent to the right ventricular wall. Therewas an atrial septal defect of the patent foramenovale type. Primary closure of the atrial septaldefect, resection of the right atrial membrane,and insertion ofa prosthetic tricuspid valve wasperformed. After operation the patient's cyan-osis resolved and tricuspid regurgitation wasno longer present.

DiscussionThe membrane seen in the reported cases ofcortriatriatum dexter is generally attributed to apersistence of the right sinus venosus valve.'28This valve forms during atrial developmentwhen the sinus venosus and other structuresare progressively incorporated into the devel-oping atria. By 12 weeks' development, thesuperior portion of the valve is absorbed intothe cristae terminalis. The remainder of theright valve typically disappears. However,small remnants of the mid and inferior aspectsof the valve occasionally persist, forming theeustachian valve of the inferior vena cava or thethebesian valve of the coronary sinus respec-tively. Failure of the membrane to regressnormally, with subdivision of the right atriuminto two distinct chambers, and no separatelyidentifiable eustachian valve is called cortriatriatum dexter.Necropsy data indicate a high incidence of

congenital abnormalities, particularly of theright heart, in patients with cor triatriatumdexter.25 These findings are attributed to thesubstantial redirection of blood by the rightvenous valve away from the right ventricle andinto the left atrium during embryogenesis.257The most common malformations include anabnormal or underdeveloped right ventricleand pulmonary artery stenosis or atresia.Abnormalities of the tricuspid valve also occur,including Ebstein's anomaly.910To our knowledge the attachment of the

membrane left of the superior vena cava but

right of the inferior vena cava and coronarysinus seen in our patient has not been describedbefore. In a review by Doucette and Knoblichthe most common location of the membranewas to the right of the superior vena cava,coronary sinus, and inferior vena cava and thesecond most common pattern found was whenthe membrane was to the left of the coronarysinus but to the right of the other two venousvessels.2 Although the mid and inferior portionof the membrane in our patient most certainlyarose entirely from the right sinus venosusvalve, the superior aspect may have arisen fromthe persistence of a skewed septum secundumand the right sinus venosus valve.2

Typical findings of cor triatriatum dexter atcross sectional echocardiography were con-firmed at necropsy in a neonate.7 In thatpatient, there were also two right atrial com-partments divided by an extensive membranewith superoinferior attachment. Contrastinjection through the inferior vena cava showedcomplete right to left shunting ofblood across apatent foramen ovale. In our patient, echocar-diography was also valuable in detecting themembrane and in further defining the presenceof Ebstein's anomaly. Using this imaging tech-nique during the catheterisation, we were ableto determine the position of the membrane inrelation to the great vessels whereas angio-graphy did not show its presence. The echocar-diographic procedure before and during cath-eterisation showed that there was no gradientbetween the two chambers on the Dopplerexamination and that there were perforations inthe centre of the membrane on the contraststudy.

1 Yater WM. Variations and anomalies of the venous valves ofthe right atrium of the human heart. Arch Pathol1929;7:418-41.

2 Doucette J, Knoblich R. Persistent right valve of the sinusvenosus. Arch Pathol 1963;75:105-12.

3 Folger GM. Supravalvular tricuspid stenosis. Am J Cardiol1968;21:81-7.

4 Jones RN, Niles NR. Spinnaker formation of sinus venosusvalve. Circulation 1968;38:468-73.

5 Hansing CE, Young WP, Rowe GG. Cor triatriatum dexter:persistent right sinus venosus valve. Am J Cardiol 1972;30:559-64.

6 Battle-Diaz J, Stanley P, Kratz C, Fouron JC, Guerin R,Davignon A. Echocardiographic manifestations of persis-tence of the right sinus venosus valve. Am J Cardiol 1979;43:850-3.

7 Alboliras ET, Edwards WD, Driscoll DJ, Seward JB. Cortriatriatum dexter: two-dimensional echocardiographicdiagnosis. J Am Coll Cardiol 1987;9:334-7.

8 Moore KL. The developing human: clinically orientedembryology. Philadelphia: WB Saunders, 1974:248-9.

9 Verel D, Pilcher J, Hynes DM. Cor triatrium dexter. BrHeart J 1970;32:714-6.

10 Gerlis LM, Anderson RH. Cor triatriatum dexter withimperforate Ebstein's anomaly. Br Heart J 1976;38:108-11.

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