Submitral Congenital Left Ventricular Aneurysm: You Recognize Only What You Know

A case of congenital left ventricular aneurysm in the submitral region has been reported in a previous issue of the Journal of Cardiovascular Echography.[1]

Unlike false aneurysm, which consists of a healed myocardial free wall rupture of a myocardial infarct,[2] congenital left ventricular submitral aneurysms are true aneurysms. As a matter of fact their wall is constituted by myocardial tissue, even if their etiology is noncoronary. Congenital submitral aneurysm is a peculiary form of left ventricular aneurysm thought to be caused by a congenital weakness in the posterior portion of the fibrous mitral annulus (immediately beneath the posterior leaflet) leading to a progressive expansion of this region of the left ventricular wall.[2] If severe, the displacement of the posterior mitral annulus results in restriction of the adjacent mitral leaflet leading to failure of leaflet coaptation and secondary mitral regurgitation. These rare aneurysms have been described predominantly in the indigenous African populations of the world,[3] although they have been reported in mixed races and Caucasian.[4]

Clinical presentation may include symptoms through diastolic overload (by virtue of their volume or by causing mitral annulus distortion and valve incompetence), thromboembolism, arrhythmias, compression of the left circumflex artery (with secondary myocardial infarction) and aneurysm rupture leading to sudden cardiac death.[5,6,7]

The case described by Raut et al. in a previous issue of the journal s a typical form of congenital left ventricular aneurysm in which mitral regurgitation is caused by distortion of the valvular ring.[1] The true incidence of submitral aneurysms is certainly underestimated, especially in the early stages when there are no clinical symptoms. Although rare, it is important that this anomaly is known and recognized by experts in cardiac imaging.[8] Surgery is the only way of treatment and should be considered in these patients to prevent major events.[9] Surgical approach is not the same in all cases depending of the extent of involvement of the posterior mitral valve annulus, aneurysm size and degree of mitral valve regurgitation; patients with involvement of the entire posterior mitral valve annulus are more likely to require mitral valve replacement.[9] Surgical failure has been reported to be related to inadequate closure of the aneurysm or to failure to identify additional aneurysm necks (50% of failures).[9] Given the different anatomic presentations, it is essential both that these rare congenital aneurysms are correctly recognized and that preoperative imaging is accurate so as to allow the surgeon to plan the best surgical strategy for each case.