Heart failure — sometimes known as congestive heart failure — occurs when the heart muscle doesn't pump blood as well as it should. When this happens, blood often backs up and fluid can build up in the lungs, causing shortness of breath.

Certain heart conditions, such as narrowed arteries in the heart (coronary artery disease) or high blood pressure, gradually leave the heart too weak or stiff to fill and pump blood properly.

Proper treatment can improve the signs and symptoms of heart failure and may help some people live longer. Lifestyle changes — such as losing weight, exercising, reducing salt (sodium) in your diet and managing stress — can improve your quality of life. However, heart failure can be life-threatening. People with heart failure may have severe symptoms, and some may need a heart transplant or a ventricular assist device (VAD).

One way to prevent heart failure is to prevent and control conditions that can cause it, such as coronary artery disease, high blood pressure, diabetes and obesity.

Symptoms

Heart failure can be ongoing (chronic), or it may start suddenly (acute).

Heart failure signs and symptoms may include:

• Shortness of breath with activity or when lying down
• Fatigue and weakness
• Swelling in the legs, ankles and feet
• Rapid or irregular heartbeat
• Reduced ability to exercise
• Persistent cough or wheezing with white or pink blood-tinged mucus
• Swelling of the belly area (abdomen)
• Very rapid weight gain from fluid buildup
• Nausea and lack of appetite
• Difficulty concentrating or decreased alertness
• Chest pain if heart failure is caused by a heart attack

When to see a doctor

See your doctor if you think you might be experiencing signs or symptoms of heart failure. Call 911 or emergency medical help if you have any of the following:

• Chest pain
• Fainting or severe weakness
• Rapid or irregular heartbeat associated with shortness of breath, chest pain or fainting
• Sudden, severe shortness of breath and coughing up white or pink, foamy mucus

Although these signs and symptoms may be due to heart failure, there are many other possible causes, including other life-threatening heart and lung conditions. Don't try to diagnose yourself.

Emergency room doctors will try to stabilize your condition and determine if your symptoms are due to heart failure or something else.

If you have a diagnosis of heart failure and if any of the symptoms suddenly become worse or you develop a new sign or symptom, it may mean that existing heart failure is getting worse or not responding to treatment. This may also be the case if you gain 5 pounds (2.3 kilograms) or more within a few days. Contact your doctor promptly.