Diverticulum of the left ventricle: etiology and surgical treatment.

Congenital left ventricular (LV) diverticula are rare findings, particularly when first diagnosed in adulthood. We describe successful surgical repair of an isolated congenital apical LV diverticulum associated with an abnormal submitral apparatus in a young adult who received his diagnosis following a peripheral embolism. We intraoperatively identified an abnormally originating belly of the posteromedial papillary muscle, which arose from the interventricular septum, causing partition of the LV cavity and forming an apical aneurysmal communicating chamber. This anatomy of abnormal papillary muscle bifurcation was possibly the mechanism for the development of the apical diverticulum and to the best of our knowledge has not previously been described. Reattachment of the abnormal belly to its normal position preserved mitral valve competence, and an endoventricular patch repair restored LV volume and geometry.