MYH6 and Myocardial fibrosis: This is manifested by increased cardiomyocyte size; myofibrillar disarray; altered LV geometry, including diminished LV chamber diameter; myocardial fibrosis; enhanced expression of fetal genes encoding atrial (Nppa) and brain (Nppb) natriuretic factor, α-myosin heavy chain (Myh6, or in rodents, Mhy7) and α-skeletal actin (Acta1); and an altered myocardial vasculature6,11–14.