Hypertrophic cardiomyopathy with cor triatriatum

This is a case of asymmetric hypertrophic cardiomyopathy with associated systolic anterior motion (SAM) of the anterior mitral leaflet, which contribute to left ventricular outflow tract (LVOT) obstruction. 

Hypertrophic cardiomyopathy is a heterogeneous group of diseases related to sarcomere gene mutations. It affects one of every 500 adults and and is the most common cause of sudden death in young athletes. Asymmetric hypertrophic cardiomyopathy is the most common morphologic variant of this disease.

Cor triatriatum is also seendemonstrated in this case. It is a rare congenital anomaly known to be associated with other inherited cardiac diseases. To the best of our knowledge, only few cases of cor triatriatum coexisting with hypertrophic cardiomyopathy has been reported.

There is wall thickening of the left ventricle with disproportionately enlarged ventricular septum, most pronounced at the anteroseptal myocardium consistent with asymmetric hypertrophic cardiomyopathy. Maximum wall thickening is measured 42 mm at the mid anterior septum. Small left ventricular cavity size is demonstrated.

Systolic anterior motion of the chord and anterior mitral leaflet with elevated flow velocity and pressure gradient across theresulting to left ventricular outflow tract suggestive of dynamic outflow obstruction wereis also demonstrated.  

There is also wall thickening involving the apical wall of the right ventricle extending to the anterior wall of the right ventricular outflow tract with a maximum wall thickness measuring 11.4 mm.

The left atrium is top normal in size. There is a linear structure (membrane) traversing the left atrial cavity attached to the secundum interatrial septum and the junction of the left inferior pulmonary vein and apical side of the left atrial wall (best seen in the 4-chamber view). This membrane divides the left atrium into a proximal chamber, containing the pulmonary venous confluence, and a distal left atrium, which may represent acontains the left atrial appendage. The left atrial findings are consistent with cor triatriatum.