Lorena Doctor MD, Sabahat Bokhari MD, Yasmin S Hamirani MD
Division of Cardiovascular Disease and Hypertension. Department of Medicine. Rutgers Robert Wood Johnson University Hospital, New Brunswick, NJ, 08901
Clinical History
A 50 year-old male with a history of hypertension (HTN) and hyperlipidemia presented with intermittent but multiple episodes of recurrent sharp chest pain with intermittent diaphoresis. He denied any precipitating events or other associated symptoms. He had initially presented 2 months before with similar symptoms. At that time, a chest x-ray was performed which was noted to be normal. A twelve-lead electrocardiogram (ECG) revealed normal sinus rhythm with no acute ST segment or T wave changes. However, left ventricular hypertrophy (LVH) was noted by Cornell’s criteria (Figure 1).
 Figure 1. ECG revealing normal sinus rhythm, no acute ST changes and LVH. |
He then completed an exercise stress test using Bruce protocol in which he exercised for 13 minutes and 2 seconds without any symptoms of chest pain. However, 1.5-2.0 mm horizontal ST depression was noted at peak stress in the inferior leads. Before his follow up in cardiology clinic he continued to have “a dozen” episodes of sharp chest pain with diaphoresis. He denied any precipitating events or other associated symptoms. At the time of his second presentation, he reported frequently exercising 3 days/week to include running and swimming regularly and specifically denied any precipitation of chest pain with exercise. The only exception to this had occurred in a single episode that occurred after a four mile run. He described this pain as soreness that he experienced only after having pushed down on the anterior chest wall. An exercise sestamibi stress test was then completed at an adequate workload on Bruce protocol (>85% age predicted heart rate). ECG findings were unchanged, and perfusion images revealed a small area of anteroseptal ischemia, and mild inferior septal ischemia. The left ventricle (LV) was dilated, the LV wall motion was normal, and the reported post stress LV ejection fraction (LVEF) was 53%. An echocardiogram revealed a LVEF of 55-60%, mild mitral valve thickening, but was otherwise unremarkable (Movie 1).
Movie 1. Transthoracic echocardiogram 2- and 4-chamber shows possible membrane in the left atrium (LA). However, it was not clearly visualized.
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After having presented with recurrent chest pain in the presence of an unchanged ECG in the presence of a persistently normal exam, and an unremarkable echocardiogram, a left heart catheterization (LHC) was discussed and recommended. He refused as he didn’t desire any invasive procedures. Subsequently, he underwent a coronary computed tomography (CT) angiogram (CCTA) scan. This revealed the following: Mild coronary artery disease with no evidence of obstructive stenosis, and a branching linear defect dividing the left atrium (LA), possibly representative of cor triatriatum (Figure 2).
 Figure 2. Coronary CT angiogram (A-E) revealing presence of membrane in the LA (red arrows). The membrane is dividing LA into two quadrants with all four pulmonary veins draining into the superior chamber. |
As a result of the CCTA that was suggestive but not definitively diagnostic of cor triatriatum, a cardiovascular magnetic resonance (CMR) was then completed.
CMR Findings
CMR was performed with and without contrast on a 1.5 T GE 450 W scanner (GE Healthcare, Chicago, IL, USA). Steady state free precession images (SSFP) localizer as well as cine images were performed. Pre contrast T1 and T2 images were acquired followed by injection of gadobutrol (Bayer Pharma AG, Berlin Germany) and late gadolinium enhanced images were acquired 10 min after contrast injection. On CMR examination normal LV size, and borderline basal septal hypertrophy was noted (basal septum 1.1 cm) with normal LV systolic function (quantitative LVEF of 57%). Normal right ventricular (RV) function was also detected (right ventricular ejection fraction of 49%). No evidence of interstitial fibrosis on T1 mapping images using modified Look-Locker (MOLLI 5,3,3) sequence (T1 value of 970 msec- normal on our scanner 975 +/- 25 msec) and extracellular volume (ECV) of 29.1% (Normal 25 +/- 4%). No evidence of myocardial edema on T2 maps. Resting myocardial perfusion was normal. Delayed enhancement imaging did not reveal any evidence of LV or RV scar except possible nonspecific inferior RV insertion site fibrosis. Right atrium was mildly dilated while LA was moderately dilated with normal pulmonary venous return into the left atrium. CMR examination confirmed the presence of a membrane (cor triatriatum sinistrum) dividing the LA cavity with all four pulmonary veins draining into the superior chamber. The membrane appeared to be partial and visualized on the inter-atrial septum side. No evidence of atrial septal defect (ASD) or ventricular septal defect (VSD) noted (Figure 3 and Movie 2).
 Figure 3. Cine SSFP images at end-diastole in four chamber (A-D), short axis (E,F), two chamber (G), and three chamber (H) revealing presence of membrane in the LA (red arrows). The membrane is dividing the LA into two quadrants with the upper quadrant receiving blood from the pulmonary veins. |
 Movie 2. 4-chamber SSFP Cine revealing presence of membrane in the left atrium. |
Conclusion
This patient had earlier rejected a LHC due to his aversion to any invasive procedure unless proven absolutely necessary. For the same reason, he rejected any idea of possible surgical intervention regarding cor triatriatum sinustrum, particularly since we are not sure if his symptoms and this finding are truly related. When last contacted and seen in follow-up visit, he was doing well, continues to exercise, and is relieved that he has no critical coronary disease causing his symptoms. He has been made aware of the long-term potential risk of possible atrial fibrillation (AF) due to possible atrial remodeling, as well as the possible development of congestive heart failure (CHF) subsequent to the pathophysiology of cor triatriatum sinustrum. He continues to experience intermittent chest pain, the character of which is unchanged. He continues to be physically active and experiences no pain with exercise. He denies any palpitations, shortness of breath, or dizziness/presyncope. He opts only for continued monitoring in close regular follow-up. He has been cleared by his primary cardiologist for exercise with no physical restrictions.
This patient has cor triatriatum sinustrum with a membranous division in the LA. This congenital heart disease (CHD), although rare, is becoming more frequently recognized in adults. This case is interesting for the following reasons: First, he presented with CHD that had not been previously recognized and/or diagnosed. Second, he did not present with typical symptoms of dyspnea, CHF, atrial arrhythmia (often AF), or exertional chest discomfort. Third, the persistence of intermittent symptoms led to additional testing which then ultimately led to the definitive diagnosis in this patient.
Perspective
Cor triatriatum is a rare condition present in 0.01-.0.4 % of all infants with CHD. In this congenital disorder, the LA (cor triatriatum sinustrum/sinister, most common) or right atrium (cor triatriatum dexter/dextrum, rare) is subdivided by a thin fibromuscular membrane resulting in 3 atrial chambers. Cor triatriaum dextrum is extremely rare.[1,2,4,10] In classic cor triatriatum (cor triatiatum sinustrum), there is abnormal incorporation of pulmonary venous structures in the LA with a fibromuscular membranous subdivision throughout the atrial chamber.[2,3,9]
Clinical presentation depends on at least three variables: the degree of stenosis in the fibromuscular membrane, the integrity of the interatrial septum (IAS), and the presence of associated cardiovascular malformations.[1,2] In the adult, cor triatriatum sinustrum may manifest as follows: Asymptomatic (found incidentally on cardiac imaging), an isolated finding with a large nonrestrictive communication between the superior and inferior LA chambers, or in association with minor congenital defects such as patent foramen ovale (PFO), ASD, or persistent left superior vena cava (SVC).[2] Other complications of cor triatriatum may include unexplained pulmonary HTN, and right sided heart failure. Systemic pulmonary embolism, and ischemic cerebrovascular accident are uncommon complications of cor triatriatum that have been reported. In infants, untreated cor triatriatum may result in failure to thrive or death.[2] An echocardiogram typically demonstrates a linear density subdividing the atrium into proximal (inferior) and distal (superior) chambers. The membrane extends from the posteroinferior to the anterosuperior wall. The proximal chamber typically receives the pulmonary venous drainage. The distal chamber usually liaises with the mitral valve and the atrial appendage.[1,2].
Cor triatriatum sinistrum is inconclusive of approximately 0.4% of congenital heart disease at autopsy. In adults with cor triatriatum, this anatomy is associated with an increased risk of developing AF. It is present in less than 0.1% of clinically diagnosed cardiomyopathies.[1,2,3,10] It is more often identified in children and is particularly rare as a new diagnosis in adults.[1,3,4,9] An incidence of 0.2% has been found among patients undergoing transesophageal echocardiography. In high volume echocardiographic laboratories, the incidence of cor triatriatum is < 1:10,000. Notably, this is anticipated to rise with the increasing use of cardiac diagnostic studies.[2] Cor triatriatum is theorized to arise from failure to resorb components of the common pulmonary vein during embryogenesis.[7] Patients commonly present with pulmonary edema as infants, unless a sizeable opening in the membrane (fenestrations) allows for adequate drainage of the affected pulmonary vein.[4, 6] This fenestration may become obstructed later in life subsequent to fibrosis and calcification which may then lead to the development of symptoms.[6] AF has been described in as many as 30% of published cases in adults with cor triatriatum.[4,6] LA dilatation from elevated filling pressures may lead to the development of AF in a manner analogous to mitral stenosis.[4,5,6] It may also eventually lead to CHF.[4,8]
Given the rarity of the diagnosis, no known formal guidelines presently exist on the optimal timing of surgical correction. It has characteristically been offered to symptomatic adults, and outcomes after surgical repair have usually been reported as excellent.[5]
References
- Zoltowska D, Kalavakunta, JK. Cor triatriatum dexter. Clin Case Rep. 2018 April 14;6 (6):1189-1190. doi:10.1002/ccr3.1526.
- Kilkenny K, Frishman W. Cor Triatriatum: A Review. Cardiol Rev 2023 Nov 15. doi:10.1097/CRD. 0000000000000626.
- Jegier, W., Gibbons J.E., Wiglesworth F. W, Cor Triatriatum: Clinical hemodynamic and pathological studies surgical correction in early life. Pediatrics. 1963; 31:255-267.
- Hayes, C, Liu, S, Tam, JW, Kass, M. Cor Triatriatum Sinister: An Unusual Cause of Atrial Fibrillation in Adults. Case Rep Cardiol. 2018. Mar 31;2018:92452519. doi:10.1155/2018/ Mar 31;2018:9242519.doi:10.1155/2018/924519.
- Talner C.N. Report of the New England regional infant cardiac program, by Donald C. Fyler, MD, Pediatrics, 1980;65 (suppl):375-461. Pediatrics. 1988;102.
- Zepeda IA, Morcos P, Castenllanos LR. Cor Triatriatum sinister identified after new onset atrial fibrillation in an elderly man. Case Rep Med. 2014;2014:674018. doi:10.1155/2014/674018. Epub 2014 Dec29.
- Jha AK, Makhija N. Cor Triatriatum: A Review. Semin Cardiothorac Vasc Anesth. 2017 Jun; 21(2):178-185.doi:10.1177/1089253216680495
- Kokotsakis J, Anagnostakou V, Almpanis G, Paralikas I, Nenekidis I, Kratimenos T, Prapa E, Tragotsalou N, Lioulias A, Mazarakis A. Cor triatriatum presenting as heart failure with reduced ejection fraction: a case report. J Cardiothoracic Surg. 2011 Jun 14:6:83. doi:10.1186/1749-8090-6-83.
- Nassar, PN, Hamdan RH. Cor Triatriatum Sinistrum: Classification and Imaging. Modalities. Eur J Cardiovasc Med. 2011 Jan;1 (3):84-87.doi:10.5083/ejcm.20424884.21.
- Miki O, J Kitagawa T, Yoshizumi Masuda Y. Fukumara, Y, Katoh I. A case report of Lucas-Schmidt II A type Cor triatriatum in neonate. 1992 Dec; 40 (12):2212-6.
Acknowledgments: Aliaa Mousa MD, Andrew Mendoza MD, Kameswari Maganti MD, and Partho P. Sengupta MD for their contributions to this case.
Case prepared by:
Pranav Bhagirath, MD, PhD
Editorial Team, Cases of SCMR
Department of Cardiology, Amsterdam University Medical Centers, Amsterdam, The Netherlands
