Heart • Learn
What Is Heart Failure?
Heart failure does not mean your heart has stopped. It means your heart is not pumping or filling as well as your body needs, which can reduce blood flow and cause fluid buildup.
It is serious, but many people live better and more stable lives when it is monitored, treated, and managed consistently.
Plain English
Heart failure means the heart is having trouble keeping up with the body's need for blood and oxygen. The heart muscle may be too weak to pump strongly, too stiff to fill properly, or both. It does not mean the heart has stopped beating.
Why it matters
Heart failure can reduce oxygen delivery and cause fluid to back up into the lungs, legs, ankles, abdomen, or other areas. Over time it can affect energy, breathing, kidney function, exercise ability, and quality of life.
What ejection fraction means
Ejection fraction (EF) is the percentage of blood the left ventricle pumps out each beat, usually measured on an echocardiogram. Normal is about 55–70%. Preserved EF is 50% or higher, mildly reduced EF is 41–49%, and reduced EF is 40% or lower. Heart failure can occur with preserved, mildly reduced, or reduced EF (HFpEF, HFmrEF, HFrEF).
How it can progress
AHA/ACC stages describe progression: Stage A (at risk), Stage B (pre-heart failure with structural changes), Stage C (symptomatic), and Stage D (advanced). Early detection, treatment, lifestyle changes, and monitoring can help slow worsening.
How diet and exercise help
Reducing sodium, following any fluid guidance, choosing heart-healthy foods, limiting ultra-processed foods, watching weight changes, and consistent safe activity can support heart failure management alongside medical care.
Metrics to monitor
Home metrics include daily weight, blood pressure, heart rate, shortness of breath, swelling, activity tolerance, sodium and fluid intake, medication timing, and sleep position. Report-based metrics include ejection fraction, chamber size, valve findings, diastolic function, pulmonary pressure, BNP or NT-proBNP, kidney function, electrolytes, hemoglobin, A1C, cholesterol, blood pressure trends, and EKG findings.
Common questions
What is heart failure?
Heart failure means the heart is not pumping or filling as well as the body needs. It does not mean the heart has stopped beating.
What is a normal ejection fraction?
The American Heart Association describes a normal ejection fraction as generally between 55% and 70%.
Can you have heart failure with normal ejection fraction?
Yes. Some people have heart failure with preserved ejection fraction, where the heart may squeeze normally but has trouble relaxing or filling properly.
What are the stages of heart failure?
The AHA/ACC staging system includes Stage A (at risk), Stage B (pre-heart failure), Stage C (symptomatic), and Stage D (advanced heart failure).