TRIM63 and myocardial infarction: In further support of this notion, elevated levels of MAFbx/atrogin-1 and MuRF1 mRNA have been observed in the myocardium following chronic heart failure induced via the ligation of the left coronary artery, a condition where reduced contractile activity of the myocardium is observed [36] and, more importantly, regular exercise training has been shown to be sufficient to significantly reduce myocardial MAFbx/atrogin-1 and MuRF1 mRNA levels following experimental myocardial infarction in rats [37].