Studies also now indicate that the failing heart may damage itself further by producing high levels of TNF-alpha, a substance known as a cytokine, which is released by the immune system when tissues are injured. High levels of TNF-alpha are known to cause fatigue, weight loss, shortness of breath, and weak pumping action, and experts now believe that high levels of the substance produced by heart cells can cause actual changes to the heart's architecture. Many symptoms of heart failure result from the congestion that develops as fluid backs up into the lungs and leaks into the tissues. Other symptoms result from inadequate delivery of oxygen-rich blood to the body's tissues. Since heart failure can progress rapidly, it is essential to consult a physician immediately if any of the following symptoms are detected.
Patients typically report that they feel out of breath after mild exertion.
If the failure progresses, the dyspnea may be so acute that the sufferer, unable to breathe, may awaken from sleep in panic. An asthma-like wheezing is another common symptom. Patients may also complain of a dry hacking cough that occurs a few hours after lying down but then stops after the patient sits up. Over time, patients lose muscle weight due to low cardiac output. When this happens, in addition to dyspnea, patients sometimes have a cough that produces a pinkish froth.