Aneurysm of the Mitral Valve in Subacute Bacterial Endocarditis

The commonest form of cardiac valvular aneurysm is the thrombo-aneurysm of Ribbert (1924), which arises by perforation of an ulcer of the valve cusp into a hollow thrombotic mass and by organization undergoes fibrosis of varying degree. Reports of such aneurysms are not infrequent in the early reports of bacterial endocarditis, but aneurysms having well-organized, smooth, fibrous walls are rare; Saphir and Leroy (1945) believe that some of them are true aneurysms resulting from the action of intra-ventricular pressure upon a portion of valve cusp weakened by valvulitis. The aneurysms affect the aortic valve more commonly than the mitral (Pelvet, 1867; Osler, 1908; Horder, 1909; von Arx, 1914; Soulie and Porge, 1937), and involve the anterior (aortic or right) cusp of the mitral valve much more often than the posterior. Habershon in 1855 described a smooth-walled aneurysm, 1P9 cm. in diameter, affecting the aortic cusp of the mitral valve, and Ogle (1858 a and b) described two smaller examples. Of the 23 cardiac valvular aneurysms collected by Pelvet, 9 affected the mitral valve. More recent instances of mitral valvular aneurysms are those of Horder