Cardiomyopathy is a group of primary diseases of the heart muscle.[1] Early on there may be few or no symptoms.[1] As the disease worsens, shortness of breath, feeling tired, and swelling of the legs may occur, due to the onset of heart failure.[1] An irregular heart beat and fainting may occur.[1] Those affected are at an increased risk of sudden cardiac death.[2]

Reference
Wiki: Ischemic myocardium