Submitral aneurysms are infrequent and they are generally described in populations from Subsaharian Africa. The aetiology is still unclear: it has been proposed that they could be caused by congenital alterations of ventricular wall, infectious events, chest trauma, cardiac surgery or Myocardial Infarction. Submitral aneurysms can induce arrhythmias, stroke, heart failure secondary to mitral insufficiency, and can facilitate infections.
We report the case of a 39-year-old Caucasian woman who was hospitalized in our Institution after relapsing fever episodes, presenting with altered state of consciousness. The ECG showed sinus rhythm and normal morphology. When she was hospitalized, laboratory test findings included normocytic anaemia (Hb 9,8 g/dl), thrombocytopenia (94×103 platelets), neutrophilia (81% neutrophils), ESR 32 mm/h, CRP 8,84, low electolyte level, procalcitonin 11,54 ng/ml. Blood culture was positive for Candida Albicans. A transthoracic echocardiogram showed normal left ventricle dimensions and wall thickness, without abnormalities of global or segmental wall motion, thickening of mitral valve leaflets, which appeared slightly hyperechogen. It was found an aneurysmatic area in correspondence of subvalvular apparatus of mitral valve, between mitral annulus and posterior papillary muscle. Mitral annulus was shifted toward the atrial roof. These findings were confirmed by a thransesophageal echocardiogram. The aneurysm measured 33×22 mm in correspondence to the atrio-ventricular junction. A cardiac MRI confirmed these morphologic alterations without evidence of infarction areas, supposing the presence of an infectious lesion. A brain MRI showed multiple and diffuse areas of altered signal referred to stroke. The patient was referred to the Heart Surgery of our Institution. Intraoperatively, a large aneurysm arose from submitral area; moreover, the posterior leaflet of the mitral valve was characterized by some fissures. The aneurysm was excluded by a direct suturing and the mitral valve was replaced with a biological valve.
In our patient, mitral annulus dislocation was evident, supporting the hypothesis of a congenital malformation that can have promoted a mycotic infection and the formation of thrombi responsible for the cerebral disease. In patients with cardiac arrhythmias or embolic events, without other motivating factors, it’s necessary to pay attention and to make a differential diagnosis with these types of aneurysms.