Myocardial noncompaction (MN) is a rare form of cardiomyopathy due to an arrest in endomyocardial embryogenesis. It is characterized by multiple prominent trabeculations with deep intertrabecular recesses in ventricular walls. The disease usually affects the left ventricle and may cause cardiac failure, arrhythmias, and systemic embolism. We would like to present two rare cases of MN with a poor long-term prognosis. The first case is an unique case in the literature having bioprosthetic valve implantation and associated with a recovery of heart failure after the operation, the second case is another interesting case because of the association of A-V complete block, and multiple structural cardiac abnormalities.