A method of treating regurgitation of a mitral valve in a patient's heart. The method includes the steps of: delivering a tissue shaping device to the coronary sinus; and deploying the tissue shaping device to reduce mitral valve regurgitation, the deploying step comprising applying a force through the coronary sinus wall toward the mitral valve solely proximal to a crossover point where a coronary artery passes between a coronary sinus and the mitral valve. The invention is also a set of devices for use in treating mitral valve regurgitation. The set includes a plurality of tissue shaping devices having different lengths, each of the tissue shaping devices being configured to be deliverable to a coronary sinus of a patient within a catheter having an outer diameter no greater than ten french.