Some people with dilated cardiomyopathy don't have any signs or symptoms in the early stages of the disease. Signs and symptoms of dilated cardiomyopathy may include: Fatigue Shortness of breath (dyspnea) during activity or while lying down Reduced ability to exercise Swelling (edema) in the legs, ankles, feet or belly (abdomen) Chest pain or discomfort Fast, fluttering or pounding heartbeat (palpitations)