This condition may develop years before it is diagnosed. Most patients will experience no symptoms and will enjoy normal activity and life expectancy. However, in many individuals the left heart dysfunction will be progressive, with significant symptoms. There is a risk of sudden death with severe heart dysfunction. Therefore, regular monitoring by a cardiologist after diagnosis is necessary.

The prognosis for adult patients with more serious forms of this defect has improved dramatically in recent years, thanks largely to innovations in drug therapy. These medications (e.g. diuretics, digitalis, anti-coagulants, ACE inhibitors) are designed to forestall life-threatening congestive heart failure and the development of ventricular arrhythmias.

Patients with dilated cardiomyopathy should avoid the consumption of alcohol and excessive salt. If arrhythmias develop, they may be treated through the implantation of pacemakers or ICDs (implantable cardioverter defibrillators). Because of the possibility that a cardiac transplant may become necessary, the patient should remain in contact with a transplantation center.