Systems, devices and methods for securing tissue including the annulus of a mitral valve. The systems, devices and methods may employ catheter based techniques and devices to plicate tissue and perform an annuloplasty. One of the methods includes positioning at least two discrete, flat first anchor elements along a first side of a tissue of the mitral valve annulus in stacked relationship and at least two other discrete, flat first anchor elements along the second side of the tissue of the mitral valve annulus in stacked relationship.