A type of heart disease in which the heart no longer pumps sufficient blood to meet the body’s needs. Diabetes is a risk factor for heart failure, but a number of measures, including tight blood glucose control, can greatly reduce this risk.
The heart is essentially a muscular pump that circulates about 2,000 gallons of blood throughout the body every day. It has four chambers: two upper chambers called atria, which receive blood, and two lower chambers called ventricles, which pump blood out. The chambers are separated by four heart valves that open and close in such a way that blood flows only in the proper direction.
Each heartbeat involves a series of expansions and contractions of the heart muscle, as the heart receives oxygen-depleted blood from the body, sends it to the lungs to release carbon dioxide and receive oxygen, and delivers the oxygen-rich blood to the heart and the rest of the body. A healthy heart adjusts its output of blood based on the body’s changing needs, pumping more blood when a person is active and less blood when he is at rest.
In congestive heart failure, the heart does not actually stop beating, but one or both of the ventricles become weak and unable to pump vigorously. As blood flow slows down, blood and fluid build up, or congest, in parts of the body. If the left ventricle is not pumping properly, blood and fluid collect in the lungs or heart; if the right ventricle is weak, fluid builds up in the legs and feet. If CHF continues untreated, the heart muscle may thicken or enlarge to compensate for its diminished pumping capacity, a change that further weakens the heart muscle.
Heart failure usually develops gradually over many years, most often as the result of underlying coronary artery disease, damage to the heart muscle from a previous heart attack, or a defective heart valve. Symptoms of heart failure include shortness of breath, persistent coughing, fatigue, chest pain, weight gain, or swelling of the feet, ankles, and legs.
It is estimated that close to 6 million Americans have heart failure. Two of the most prominent risk factors for heart failure are hypertension (high blood pressure) and diabetes. Not only do people with diabetes tend to have a cluster of risk factors for heart diseases, including hypertension, obesity, insulin resistance, and abnormal blood lipid levels, but diabetes itself is also an independent risk factor for the condition. People with diabetes are two to eight times more likely to develop heart disease than the general population.
Everyone can minimize his risk of heart failure by controlling behaviors that can lead to heart disease. Lifestyle measures that reduce heart disease risks include not smoking, maintaining a healthy weight, limiting alcohol intake or abstaining from alcohol, reducing salt and fat in the diet, exercising regularly, and taking drugs as needed to control high blood pressure or abnormal blood lipid levels.
For people with diabetes, there is growing evidence that controlling blood glucose levels is critical to preventing heart disease. A 2001 study reported in the medical journal Circulation followed 48,858 men and women with diabetes and no known history of heart failure who were enrolled in a health maintenance organization in California. Over a period of roughly two years, 935 of them (close to 2%) developed heart failure that led to hospitalization or death. While this may seem like a relatively small percentage, the researchers also found that for every 1% increase in glycosylated hemoglobin (HbAlc), the risk of heart failure increased by 8%.
Heart failure cannot be cured, but it can be successfully managed. A number of effective drug treatments are available to keep heart failure in check, including the following:
- Angiotensin-converting enzyme (ACE) inhibitors. Often the main treatment for CHF, these drugs inhibit narrowing of blood vessels and lower blood pressure so the heart doesn’t have to work as hard to pump blood.
- Digitalis. A drug that makes the heart pump blood more effectively by increasing the force of the contractions and slightly slowing the heartbeats.
- Diuretics. Sometimes called water pills, they reduce the body’s retention of salt and fluid by stimulating more frequent urination. Diuretics are prescribed for high blood pressure as well as for CHF.
- Hydralazine. Another blood pressure drug, hydralazine widens blood vessels to ease the flow of blood and oxygen to the heart.
- Nitrates. These drugs widen blood vessels, reduce blood pressure, and treat chest pain associated with heart failure.
A person with mild heart failure can continue to perform most activities without difficulty, but severe CHF may require a heart transplant. Early diagnosis is the key to slowing the progression of the disease. Often, a doctor can diagnose heart failure by taking a person’s medical history and blood pressure and performing a physical exam with a stethoscope. To determine the cause and extent of the symptoms and the best treatment, the doctor may also recommend x-rays; blood tests; an electrocardiogram (ECG) test, which records the electrical activity of the heart; or an echocardiogram test, which uses sound waves to produce a video image of the heart.