ATM and myocardial infarction: Moreover, ROS also stimulate inflammatory cytokine production and extracellular matrix degradation, promoting left ventricular dilation and heart failure.19, 37 It is known that ATM is an important sensor of ROS17 that also maintains ROS balance.38 Our present study showed that ATM haplodeficiency increases the expansion index and worsened heart failure, which may be attributed to an ROS imbalance after MI (Figures 3 and 4).