Initially you may not feel any symptoms of dilated cardiomyopathy, or symptoms such as fatigue or weakness may be mild.

Eventually, you will develop heart failure. Symptoms of heart failure can develop gradually, over months or years. In other instances, heart failure may develop suddenly, such as after a viral infection or pregnancy.

Symptoms of gradual heart failure

Typically, symptoms of heart failure develop gradually and may include:

• Weakness and fatigue.
• Difficulty breathing and/or wheezing during normal activities or exercise that did not cause breathing problems in the past.
• Shortness of breath.
• A dry, hacking cough, especially when lying down.
• Fluid buildup (edema), especially in the legs, ankles, and feet.
• Dizziness, fainting, or feeling tired or weak.
• Heart palpitations.
• Rapid weight gain caused by water retention.
• Increased urination at night.
• Abdominal swelling, tenderness, or pain, which may result from a buildup of fluid in the body (ascites) and blood that backs up in the liver.

Symptoms of sudden heart failure

In sudden heart failure, rapid fluid buildup in the lungs may cause symptoms of pulmonary edema, such as:

• Severe shortness of breath.
• Irregular or rapid heartbeat.
• Coughing up foamy, pink mucus.

Sudden heart failure is an emergency medical situation and requires immediate care.

Complications of dilated cardiomyopathy

Complications of dilated cardiomyopathy may include:

• Pulmonary edema, which is rapid fluid buildup in the lungs.
• Arrhythmias, which are abnormal heart rhythms that can cause loss of consciousness or sudden death.
• Blood clots inside the heart, which can lead to a stroke or heart attack.

Dilated cardiomyopathy is the most common type of cardiomyopathy. Other forms of cardiomyopathy include restrictive cardiomyopathy, in which the heart muscle gets stiff, and hypertrophic cardiomyopathy, in which the heart muscle is thickened and can't relax. For more information, see the topics Hypertrophic Cardiomyopathy and Restrictive Cardiomyopathy.