Thrombosed aneurysm of the left sinus of valsalva presenting as an intramyocardial mass.

Aneurysms of the sinuses of Valsalva are uncommon in clinical practice. Most are congenital, but secondary causes are also recognized. Congenital aneurysms of the left sinus of Valsalva are particularly rare. The authors report a fatal case in which a nonruptured aneurysm of the left sinus of Valsalva dissected into the interventricular septum and presented as heart failure. The concurrent presence of dilated cardiomyopathy and the mechanisms that may have led to it are discussed on the basis of the anatomic and histologic features found at autopsy.