Congestive heart failure (CHF) can result from either a reduced ability of the heart muscle to contract or from a mechanical problem that limits the ability of the heart's chambers to fill with blood. When weakened, the heart is unable to keep up with the demands placed upon it; blood returns to the heart faster than it can be pumped out so that it gets backed up or congested.
The heart attempts to compensate for the congestion, or backup, of blood in a number of ways. It beats faster and expands somewhat more than usual as it fills with blood, so that when it contracts, more blood is forced out to the body. In addition, the decreased volume of blood reaching the kidneys causes them to start a hormonal cascade, which causes them to retain sodium and water, resulting in swelling or edema. These efforts help meet the body's demands in the short term, but they ultimately have very harmful long-term effects. Faster beating allows less time for the heart to refill after contraction, so less blood ends up being circulated. The increased effort means the heart muscle needs more oxygen, and if this need isn't met, it can be fatal.
Heart failure symptoms include:
•Shortness of breath and wheezing after limited physical exertion. In advanced cases shortness of breath occurs even at rest, and attacks of severe breathlessness disturb sleep (left-sided failure).
•Severe fatigue and weakness.
•Dry cough or cough that produces frothy or bloody sputum (left-sided failure).
•Frequent urination during the night (right-sided failure).
•Swelling of the ankles and feet
•Rapid weight gain due to fluid retention (right-sided failure).
•Abdominal pain and a feeling of fullness (right-sided failure).
•Swollen neck veins (right-sided failure).
•Loss of appetite (anorexia); nausea and/or vomiting.
•Irregular or rapid heartbeat.
•Anxiety; in severe cases irritability, restlessness, and mental confusion may occur.