Left ventricular pseudo aneurysm (LVPA) (or false aneurysm) is a rare condition and forms when cardiac rapture is contained by pericardial adhesions or fiber tissue. The most common cause of LV pseudoaneurysm is myocardial infarction (MI) (over 50%) followed by previous heart surgery (about 1/3 of the cases), trauma (over 5%) and infection (about 5%). Post-infraction pseudo aneurysms (PIPA) are characterized as acute when they are diagnosed within the first two weeks from the infraction and as chronic when they are discovered later than a 14-day period from the event. The clinical presentation may vary depending upon congestive heart failure, mitral regurgitation, ventricular tachy-arrhythmia, systemic thrombo-embolism and cardiac rupture [1, 2]. In general, patients do not have specific symptoms pertaining to pseudo aneurysm , hence the diagnosis may be delayed. Wall stress, which is related to LV pressure and radius, and loss of myocardial integrity, because of the infraction, are the most probable reasons of cardiac rapture. Pathologically, LVPA have a narrow neck [3, 4] that connects the heart chamber with a large aneurismal sac, which contains blood and thrombus and is lined by fibrous pericardial tissue with no myocardial elements. On the contrary, true post-infraction aneurysms have a larger point of entry caused by scar formation which results in thinning of the myocardium . Angiography, transthoracic or transoesophageal echocardiography, CT-scan and MRI are the imaging modalities which are used in the diagnostic process of LVPA, with the first two being the most reliable and frequently used [3, 5, 6].
When a LVPA is discovered, surgical repair is performed in most cases. Surgery is the recommended treatment for PIPAs diagnosed within the first sixty to ninety days after the myocardial infarction, because there is high possibility of rupture. On the other hand, when the discovery of a LVPA is made months or even years after the infarction, surgery is not the treatment of choice [3, 4]. Left ventricular pseudo aneurysms can be repaired with various techniques depending on the time interval between the infarction and LVPA’s diagnosis. Chronic pseudo aneurysms can be repaired by direct suturing of the neck with horizontal mattress sutures buttressed with Teflon felt strips and a patch secured over the repair. In acute cases, epicardial repair can be performed by placement of a patch of pericardium, Dacron, or polytetrafluoroethylene (PTFE) over the ventricular defect; the patch is sutured to healthy myocardium along the periphery of the infarct. In the case discussed here the LVPA occurred as a result of rupture of the LV and the wall was composed of only the epicardium along with clots and fibrin. Thus the treatment of choice was the exclusion and synthetic patch replacement as in Dor procedure. Direct over sewing with buttress sutures was not an option due to tissue friability. False aneurismal wall can either be removed or sewn over the patch .
Giant LV pseudo aneurysm has been reported to cause mitral regurgitation and compression of adjacent vascular structures [7–9]. However, in the present case the aneurysm was actually mistaken for an insufficient mitral valve with vegetations. This impression is by all means uncommon and to our knowledge unique in the relevant literature. The febrile and septic status of the patient might have been a potential misleading factor; the position of the false lumen another. The second TTE along with the TOE revealed the actual LVPA and excluded the initial impression of the infected mitral valve (MV). Thus, in such cases of suspected MV endocarditis the additional confirmation with the TOE should always be encouraged. In the present case, relying on the first TTE for planning of the operation would have had catastrophic consequences for the patient. Once the diagnosis of LVPA is confirmed, further delineation can be obtained via CT scanning.