Clinical History
A 26 year old asymptomatic male incidentally diagnosed with AF during a casual check up. He was hospitalized in the department of cardiology for further examinations. An anomalous structure was found in the cardiac echo examination. Patient was sent to our radiology department for cardiac CT and MR.
Imaging Findings
The patient had no history of heart disease or other complaints.
ECG: AF with a heart frequency of averagely 90 bpm.
CARDIAC ECHO: Dilated LV with decreased systolic function (EF 42%). The LA was dilated and with turbulent flow. An abnormal structure was visualized in the left atrium with the same echogenity. No communication was found between the lesion and the atrium.
CARDIAC MR examination (Avanto, Siemens) demonstrated dilated LA with a membrane separating the left atrium into two chambers; the bigger one was posteriorly located and received the pulmonary veins, and the smaller one anteriorly located contained the atrial appendage and mitral valve.
These two chambers communicated with each other through a defect in the anteromedial segment of the membrane creating a turbulent flow through the membrane and inside the atrium in the gradient echo cine images.
Cardiac CT examination (Somatom Sensation, Siemens) showed the membrane with mild calcifications especially in the level of communication of two chambers. No other cardiac anomalies were found.
Discussion
Cor triatriatum is a heart with 3 atria (triatrial heart), and is a congenital anomaly in which the left atrium (cor triatriatum sinistrum) or right atrium (cor triatriatum dextrum) is divided into 2 parts by a fold of tissue, a membrane, or a fibromuscular band. Classically, the proximal (upper or superior) portion of the corresponding atrium receives venous blood, whereas the distal (lower or inferior) portion is in contact with the atrioventricular valve and contains the atrial appendage and the true atrial septum that bears the fossa ovalis. The membrane that separates the atrium into 2 parts varies significantly in size and shape. It may appear similar to a diaphragm or be funnel-shaped, band-like, entirely intact (imperforate) or contain 1 or more openings (fenestrations) ranging from small, restrictive-type to large and widely open.
In the pediatric population, this anomaly may be associated with major congenital cardiac lesions such as tetralogy of Fallot, double outlet right ventricle, co-arctation of the aorta, partial anomalous pulmonary venous connection, persistent left superior vena cava with unroofed coronary sinus, ventricular septal defect, atrioventricular septal (endocardial cushion) defect, and common atrioventricular canal.
In the adult, cor triatriatum is frequently an isolated finding.
In our patient the large size of the defect between two chambers approximately 10mm likely accounted for the late onset of symptoms that allowed this patient to survive into adulthood without previous diagnosis or surgical intervention (which is usually required in childhood).
Differential Diagnosis List
Isolated Cor triatriatum sin.
Final Diagnosis
Isolated Cor triatriatum sin.
