(A) The number of LC3B dots was elevated in the failing hearts, while treatment with AICAR significantly reduced the number of LC3B dots, suggesting decreased autophagy in the failing hearts following AMPK activation. Moreover, in mice treated with AICAR, remarkable inhibition of autophagosome formation was detected using electron microscopy (B). However, in hearts that did not undergo AB surgery, AICAR markedly increased autophagy (A,B).