As discussed in  Chap. 66, the surgical treatment of valvular heart disease that leads to LV dysfunction or heart failure is now widely accepted. However, patients who have valvular dysfunction secondary to a primary cardiomyopathy pose a much more difficult management problem. The following section focuses on the impact and outcome of valve repair or replacement for patients with a dilated cardiomyopathy and secondary mitral regurgitation. The indications for valve replacement in ischemic mitral regurgitation are discussed in  Chap. 66.