abnormal muscle morphology abnormal cardiac muscle tissue morphology 2010-10-07T10:28:22Z Do not confuse cardiac muscle tissue with the myocardium. Myocardium consists primarily of cardiac muscle but these structures are not identical. Cardiac muscle tissue also exists outside the heart so this term has not been made a child of heart myocardial layer directly. MP:0010630 MPheno.ontology abnormal cardiac muscle morphology abnormal heart muscle morphology any structural anomaly of the involuntary muscle comprising the myocardium of the heart and the walls of the pulmonary veins and superior vena cava; cardiac muscle is striated and multinucleate, and the cardiomyocytes branch and are joined to one another via intercalated discs cardiac muscle abnormalities cardiac muscle dysplasia csmith