Cor triatriatum sinister.

C triatriatum is a very rare congenital cardiac anomaly with no known associated genetic abnormalities. Cor triatriatum is generally an isolated anomaly but may be associated with anomalous pulmonary venous return in approximately 10% of patients, patent ductus arteriosus, left superior vena cava, ventricular septal defects, Shone syndrome, tricuspid atresia, Ebstein malformation, atrioventricular canal, and tetralogy of fallot.1 Here, we describe a male with cor triatriatum who presented with progressive dyspnea upon exertion. A 24-year-old active male presented with progressive dyspnea upon exertion and palpitation from 2 months ago (Functional Class 2 late, New York Heart Association). There were no significant symptoms earlier in life. He had a history of severe common cold one month ago that resolved spontaneously without any treatment. Upon physical examination, he had sinus tachycardia, normal blood pressure, clear lung, accentuation of second heart sound, apical holosystolic murmur grade 2/6 with radiation to the axilla, and no central cyanosis. Other systems were normal. Electrocardiogram showed left atrial enlargement with nonspecific ST-T changes. Chest xray showed mild increase in cardiac size with pulmonary venous congestion, left atrial and left atrial appendage enlargement. Transthoracic echocardiography showed mild left ventricular enlargement, mildly reduced ejection fraction, and discrete membrane in the left atrium that subdivided this chamber to 2 separate parts. Mitral valve and left atrial appendage were in the distal chamber and foramen ovale and pulmonary veins in the proximal chamber. There was mild mitral valve thickening and regurgitation and tricuspid regurgitation in echocardiography (Figure 1). Doppler study showed a typical turbulent flow across the membrane with a 20 mm Hg gradient and a systolic pulmonary artery pressure of approximately 55 mm Hg. Transesophageal echocardiography was refused by the patient. Cardiac catheterization showed moderate pulmonary hypertension with 20 mm Hg gradient between wedge pressure and left ventricular end diastolic pressure. Dye injection in the pulmonary artery with late opacification (Levophase) showed no abnormalities in pulmonary venous return, and a delicate and discrete membrane inside the left atrium with 2 separate chambers. No other associated congenital cardiac anomalies were found. Left ventricular size was enlarged mildly with good ejection fraction and mild mitral regurgitation (one degree). Surgery was planned. Median sternotomy was performed. Open correction was performed on cardiopulmonary bypass through atrial incision with complete resection of the diaphragm. This was a single perforation in the center of the diaphragm. There was no significant residual regurgitation on mitral valve. Foramen ovale was in the proximal chamber, but the left atrial appendage was in the distal. Tissue sample was sent for pathological evaluation. He was disconnected from the pump easily with satisfactory homodynamic. After 6 days, he was discharged from the hospital in good condition. Echocardiography, one month after surgery exhibited normal left ventricular size with a good ejection fraction, disappearance of stenotic diaphragm, mild mitral regurgitation and normal pulmonic pressure. Currently, he is in good condition without any problem. The membrane is composed of a histological structure similar to the wall of pulmonary vein (bases). The membrane contains an outer thin endothelial lining (smooth wall) with its sub endothelial layer of loose connective tissue. Below this membrane, there are myocardial muscle fibers running in isolated but parallel direction. The nuclei were shrunken in size, but there is no evidence of myocardial fiber degeneration and infiltration of inflammatory cells. Cor triatriatum is a very rare congenital malformation, occurring in 4% of patients with cardiac defects. There are no known risk factors or associated genetic abnormalities. This anomaly is generally considered to be a result of faulty incorporation of the common pulmonary vein into the left atrium so that pulmonary veins do not directly join to the left atrium. The foramen ovale and the left atrial appendage usually communicate with the distal left atrium (true Clinical Notes