Coronary sinus ring apparatus, including an elongated body for deployment in a coronary sinus, an aperture in a long side of the body, at least a partial lumen extending from one end of the elongated body to at least the aperture, and a guide within the elongated body positioned and shaped to guide an element inserted along the lumen to the aperture. Apparatus for treating a heart, including a delivery tube sized for and adapted for insertion into a body, a sharp tip adapted to be pushed through cardiac muscle, an elongate tensioning element, and a foldable anchor adapted to couple the elongate tension element to cardiac muscle tissue, wherein the delivery tube encloses one or both of the elongate tensioning element and the foldable anchor. Related apparatus is also described.
