congestive heart failure
Meaning of congestive heart failure: The word failure misleads, since the heart keeps beating; what fails is the match between its output and what the body needs.
Definition of congestive heart failure
Congestive heart failure is a condition in which the heart cannot move blood forward well enough to meet the body's needs, so fluid backs up into the lungs, the legs or the abdomen. The heart does not stop. It works less efficiently, and the body's own attempts to compensate eventually make the problem worse.
What goes wrong with the pump?
Two mechanical faults produce the same syndrome, and telling them apart shapes how the condition is monitored.
| Type | What the heart does | Common background |
|---|---|---|
| Reduced pumping strength | The muscle contracts weakly and ejects a smaller share of the blood in the chamber with each beat | A previous heart attack, coronary artery disease, a virus or a toxin that damaged the muscle |
| Preserved pumping strength | The muscle squeezes normally but is stiff and fills poorly between beats, so less blood is there to eject | Long standing high blood pressure, aging, diabetes, obesity |
Valve disease, an abnormal rhythm and heavy alcohol use can produce either, and some cancer treatments damage heart muscle in the same way.
Why does fluid collect where it does?
Blood returning to a chamber that cannot clear it backs up along the path that fed it. When the left side is failing, the backup extends into the lungs, producing breathlessness that is worse lying flat and, in severe cases, the sensation of drowning. When the right side is failing, the backup extends into the veins of the body, producing swollen ankles and legs, a distended vein in the neck, an enlarged liver and fluid in the abdomen. Left sided failure is the usual cause of right sided failure, so most people eventually have features of both, which is what the word congestive refers to.
Why does compensation make it worse?
Faced with reduced output, the body responds as though blood had been lost. Hormone systems shared with the kidneys tell the body to retain salt and water and to tighten blood vessels, and the nervous system drives the heart faster and harder. Each response raises blood pressure and volume briefly, which helps in an emergency and is counterproductive in a failing heart: more volume to shift, more resistance to push against, and a heart muscle driven harder while already struggling. That cycle drives the gradual worsening, and it explains why the condition is closely linked with kidney failure, since the two organs share the same regulating systems.
Also known as
Used in a sentence
The patient's worsening shortness of breath and leg swelling were attributed to an exacerbation of congestive heart failure.
Good to know
Congestive heart failure can involve reduced pumping strength, impaired filling of a stiffened heart muscle, or both, a distinction that affects how the condition is classified and monitored.