heart failure
Imagine a water pump that has been running for years and is starting to wear out. It still turns, but it can no longer push water through the house fast enough, so pressure backs up behind it and the taps upstairs run weak. Heart failure is that situation in the body: the heart still beats, but it cannot move enough blood forward to meet the body's needs without pressures rising behind it.
More precisely, heart failure is a clinical syndrome — a recognizable pattern of symptoms and signs — caused by any structural or functional problem that impairs the heart's ability to fill with blood or to eject it. Typical features include breathlessness, fatigue, and fluid retention causing swelling. It is the end stage of many different heart diseases, including coronary artery disease, long-standing high blood pressure, valve disease, and cardiomyopathy.
A common misconception is that heart failure means the heart has stopped or is about to stop. It does not. The word ‘failure’ describes failing performance under load, not an arrest. Many people live for years with treated heart failure, and modern therapy can substantially improve both symptoms and survival. The body also fights back through compensatory mechanisms, which help in the short term but often worsen the disease over time.
A 68-year-old reports climbing one flight of stairs now leaves her gasping, her ankles swell by evening, and she sleeps propped on three pillows. An echocardiogram shows a weakened pump, and a blood test for natriuretic peptide is high — together pointing to heart failure.
Symptoms, imaging, and a blood marker together establish the diagnosis.
Heart failure is classified in several overlapping ways: by ejection fraction (reduced vs preserved), by which side fails first (left vs right), and by speed of onset (acute vs chronic). These labels guide treatment, so clinicians often combine them.