None — Heart Failure
Heart failure occurs when the heart becomes too weak to adequately pump blood through the circulatory system. In left-sided heart failure, the heart has difficulty pumping oxygenated blood to the organs and tissues. In right-sided heart failure, the heart is unable to adequately pump deoxygenated blood back to the lungs, where carbon dioxide is released and exchanged for oxygen.
In the early stages of heart failure, the heart enlarges so it can pump more strongly. The heart may also pump faster to increase the amount of blood it sends to the body. Eventually, those methods of compensation slowly stop working. Fluid can build up in the lungs, causing shortness of breath, and in other parts of the body (especially in the feet, ankles, legs and abdomen). Patients may also develop a chronic cough, wheezing, fatigue, rapid or irregular heartbeat, chest pain (angina), loss of appetite, nausea and confusion or mental impairment.
According to the American Heart Association, about 5.8 million people in the U.S. have heart failure. The condition was listed as the cause of death for more than 282,750 Americans in 2006. Risk increases with age. Heart failure is more common in people 65 and older, with risk doubling every decade of life. Heart failure is also more prevalent in African-Americans, people who are overweight, those with prior heart attack or disease affecting the heart muscle or valves, and patients with high blood pressure, arrhythmias, diabetes, lung disease, anemia and kidney disease.
Treating Heart Failure
Initially, treatment for heart failure may involve a healthy diet, weight loss, monitoring fluid intake, a prescribed exercise program, rest and smoking cessation. Medications may also be prescribed to reduce fluid build-up, reduce strain on the heart and improve the heart's pumping ability.
When patients have severe heart failure, doctors may recommend cardiac resynchronization therapy (CRT). This treatment involves the surgical implantation of a special pacemaker. Standard pacemakers use two wires, one attached to each chamber (upper and lower) on the right side of the heart. The pacemaker monitors the heart beat and delivers a small electrical shock when the heartbeat becomes too slow, stimulating the heart back into a normal beat. The CRT uses a third wire that connects to the left ventricle (the lower, main pumping chamber). This enables the heart to be stimulated on both the right and left sides. The advantage of the system is that the heart can be stimulated to contract in a coordinated fashion, leading to a stronger and more effective heart beat.
Researchers have found CRT therapy is very beneficial for patients with severe heart failure. A recent study found death rates among patients receiving CRT were 31 percent lower than among those receiving standard therapy.
A New Device Option
Researchers theorized that since CRT is so beneficial for patients with severe heart failure, those with significant heart disease may benefit as well. Arthur Moss, M.D. Researcher with the University of Rochester Medical Center in Rochester, NY, explains patients with severe heart disease are at high risk for heart failure and have a five-fold increased risk of death.
In the MADIT-CRT study, 60 percent of the patients were randomly assigned to receive CRT-D (a CRT and defibrillator) and 40 percent received an Implantable Cardioverter Defibrillator (ICD). Both groups also received other standard treatments for their heart symptoms. Average follow-up time was 2.4 years.
The investigators found those who received the CRT-D had a 34 percent reduction in development of serious heart failure or death compared to those who received only the ICD. The results were most impressive for women. Researchers report women with mild heart disease who received CRT-D had a 70 percent reduction in heart failure and 72 percent reduction in death.
The MADIT-CRT study is still ongoing, but no longer seeking participants. For information on the trial, click here, then type the trial identification number in the search box: NCT00180271.
For general information on heart failure:
American Heart Association Heart Failure Online Heart Rhythm Society National Heart, Lung and Blood Institute
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