DNAH8 and Myocardial fibrosis: In addition, TAC caused myocardial fibrosis, apoptosis, upregulation of βMHC expression and downregulation of αMHC (αMHC/βMHC switch) which collectively resulted in contractile dysfunction (i.e., reduction of myofibrillar ATPase activity, cardiac myofiber shortening and velocity of shortening), overt heart failure and significant mortality (Figures 1 and 4 and Table 1).