Cor Triatriatum Sinistrum Presenting as Cyanotic Congenital Heart Disease: A Rare Case Report

Cor Triatriatum Sinistrum Presenting as Cyanotic Congenital Heart Disease Gokhroo R et al J Cardiothorac Med. 2015; 3(1):278-280. 279 Figure 1. 2 D echo subcostal 4 chamber view showing RA, RV, LV; upward pointing arrow denotes the membrane dividing left atrium into two chambers visualised as a linear echogenic structure with a stenotic opening. Horizontal arrow denotes ASD with atrial septal aneurysm. (*) distal LA compartmentLA proper, (◊) proximal LA compartmentvenous chamber, RAright atrium, RVright ventricle, LVleft ventricle dilated. Afterwards, the right atrium and the right ventricle were enlarged. The LA and the cardiac valves were normal. Mild tricuspid regurgitation with severe pulmonary artery hypertension (RVSP = 94 mm Hg) was present as well. On the Doppler color flow imaging, a turbulent, continuous flow from the proximal LA chamber to the distal left atrial chamber was detected (Figure 2). The main cause of the respiratory distress was still unknown to us. Reviewing the background of the cyanotic infant, we suspected that there might be a case of intracardiac right-to-left shunt. To confirm the right-to-left shunt, Saline Contrast Echocardiography was performed through the left antecubital vein revealing the appearance of bubbles: first, in the right atrium followed by the LA. Then, there was an almost simultaneous appearance of the bubbles in both of the ventricular chambers suggesting a communication from the right atrium to the distal left atrial chamber while Figure 3. Saline contrast echo demonstrating opacified RA, RV, distal LA compartment and LV and non opacified proximal LA compartment with negative contrast effect into distal LA chamber (*) Figure 2. Colour flow imaging subcostal 4 chamber view showing proximal to distal LA compartment colour flow via stenotic opening (arrow) the proximal compartment of the LA was not opacified (Figure 3). The failure of contrast opacification of coronary sinus (Figure 4) during this maneuver ruled out the possibility of persistent left superior vena cava. Furthermore, the Saline Contrast Echo appeared as negative in the distal left atrial compartment which was indicative of an inflow from the proximal left atrial chamber. Discussion Cor triatriatum sinistrum is a rare congenital anomaly in which a fibromuscular membrane divides the left atrium into two chambers. In the process, the accessory (proximal) chamber communicates with the distal chamber, the true left atrium which includes the left atrial appendage, through one or more openings (2). These openings could be classified into the three following types: diaphragmatic, hourglass or tubular. In the diaphragmatic type, the membrane is oriented horizontally and it does not alter the anatomy of the chambers. This is the most prevalent of all types and it is the one detected in the present case. Figure 4. Saline contrast echo demonstrating dilated coronary sinus with absent contrast bubbles (*) Gokhroo R et alCor Triatriatum Sinistrum Presenting as Cyanotic Congenital Heart Disease 280J Cardiothorac Med. 2015; 3(1):278-280.With reference to the hourglass type, thejunction between the accessory chamber and thetrue left atrium is constricted externally while inthe tubular type, the confluence of the pulmonaryveins communicates with the left atrium througha channel.Generally, around 70-80% of cor triatriatumcases are associated with other cardiacanomalies. The most frequent association (50-60% of all cases) is either patent foramen ovaleor Ostium Secundum Atrial Septal Defect, whichis usually between the right atrium and the distalchamber (3). Other associated defects are notproven to be as prevalent (4, 5).In the classic cor triatriatum where there isno alternative pathway for the pulmonary venousblood, the stenotic opening in the membraneresults in the supravalvular mitral stenosis withall the features of the elevated pulmonary venouspressure which are transmitted to the lungscausing pulmonary edema; the features thatdetermine the condition of the patient. If theopening is 3 mm in diameter or less, thesymptoms emerge in infancy and are similar tothose of the total anomalous pulmonary venousreturning with obstruction. If the opening islarger, the symptoms manifest later in infancy,childhood or occasionally later in life (6).Most patients with this anomaly succumbwithin the first few months of life. Nonetheless,there is the exception of those patients with anadequate size of orifice in the membrane whomight survive until their teens and even intoadulthood. Death is likely to occur with pulmonaryoedema, pneumonia or right-sided failure.Predominantly, cor triatriatum sinistrumrepresents as an acyanotic congenital heartdisease. Our patient had a rare cyanoticpresentation of the disease. She had persistentpulmonary arterial hypertension of newbornleading to the right-to-left atrial shunt through anatrial septal defect, hence the systemicdesaturation and cyanosis. On the other hand, thepulmonary venous hypertension caused by thestenotic left atrial inflow was regarded as apossible mechanism for the failure in the naturalregression of the high pulmonary vascularresistance of the newborn.The differential diagnosis of this diseaseinclude the total anomalous pulmonary venousconnection to the coronary sinus or the rightatrium, pulmonary vein stenosis and partialanomalous pulmonary venous connection whichare all effectively discriminated on Routine 2Dand Contrast Echocardiography obviating theneed for more cumbersome and sophisticateddiagnostic modalities.ConclusionTo the best of our knowledge, cor triatriatumpresenting as a cyanotic heart disease is quite ararity. This case report underscores the diagnosticvalue of echocardiography. The diagnosis of cortriatriatum sinistrum is commonly made onTransthoracic Echocardiography and SalineContrast 2D Echocardiography is also known to beuseful in delineating various chambers, flow andshunts which may avoid the need for moresophisticated imaging modalities in unstablepatients.Conflict of interestsThe author has no conflict of interests.References1. Krabil KA, Lucas RV Jr. Moss and Adams HeartDisease in infants, children and Adolescentsincluding the fetus and young adult. 5th ed. Vol 1.Philadelphia: Lippinkott William and Wilkins;1995. Abnormal pulmonary connections; pp. 863-8.2. Jacobstein MD, Hirschfeld SS. Concealed left atrialmembrane: pitfalls in the diagnosis of cortriatriatum and supravalve mitral ring. Am JCardiol. 1982; 49:780-6.3. Van Praagh R, Corsini I. Cor triatriatum: Pathologicanatomy and a consideration of morphogenesisbased on 13 postmortem cases and a study ofnormal development of the pulmonary vein andatrial septum in 83 human embryos. 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