Herein, we present evidence in male rats that chronic AT1R blockade up-regulates AT1R/PKCδ and alters miR expression profiles in the left ventricle, leading to increased cardiac vulnerability to acute onset of myocardial ischemia and reperfusion injury and decreased recovery of left ventricular function immediately after ischemic injury. This evidence concerns the gene AGTR1 and myocardial ischemia.