Mitral valve aneurysm and infective endocarditis: report of four cases.

From March 1992 to March 1994, four cases of mitral valve aneurysm were diagnosed at National Taiwan University Hospital. Mitral valve infective endocarditis was documented in three patients, while aortic valve infective endocarditis was found in the other. The diagnosis of mitral valve aneurysm was based on characteristic echocardiographic findings. The mitral valve aneurysms in these four cases were all visualized by transesophageal but not transthoracic echocardiography. At the time of diagnosis, three patients with a history of mitral valve endocarditis had perforated mitral valve aneurysms and severe mitral regurgitation. Although not found before surgery, the remaining patient with a history of aortic valve endocarditis was noted to have an unperforated mitral valve aneurysm one month after aortic valve replacement. All three patients with severe mitral regurgitation underwent mitral valve replacement and the patient with an unperforated mitral valve aneurysm was managed conservatively and obtained a stable clinical condition. In conclusion, mitral valve aneurysm usually appears to be associated with infective endocarditis and transesophageal echocardiography is more helpful in the diagnosis of mitral valve aneurysm than transthoracic echocardiography. Furthermore, unperforated mitral valve aneurysms may be managed conservatively with careful follow-up.