CONGESTIVE HEART FAILURE
Peter J. Sharis, MD
What is congestive heart failure?
If you have congestive heart failure it means your heart does not work as well as it should, which leads to high pressure inside the chambers of the heart. This can be the result of weak and/or stiff heart muscle. Symptoms of congestive heart failure include shortness of breath with activity, problems breathing when lying down, waking up at night short of breath or coughing, going to the bathroom many times at night, swollen feet or ankles, and general weakness or fatigue.
What causes congestive heart failure?
Congestive heart failure typically occurs when another problem makes the heart muscle weak. Coronary artery disease, which is due to cholesterol buildup (atherosclerosis) in the heart's own blood vessels, is a common cause of congestive heart failure. This buildup can lead to severe narrowings that reduce blood flow to the heart and make it pump weakly. When cholesterol plaques crack or rupture, the resulting turbulent blood flow can lead to clot formation and near complete or complete occlusion of the blood vessel, which results in a heart attack. A heart attack causes permanent scarring or damage to the heart, thus decreasing overall heart function and making congestive heart failure more likely to occur.
Another condition that contributes to congestive heart failure is high blood pressure. Individuals with high blood pressure often have a thick, muscular left ventricle, which is the main pumping chamber of the heart. When the muscle gets too thick, it starts to fail to relax adequately between heartbeats (during diastole). This can lead to congestive heart failure from diastolic dysfunction. About one-third of congestive heart failure cases have a diastolic dysfunction component.
Problems with the heart's valves also can lead to congestive heart failure. For example, if the aortic valve, which regulates blood flow from the left ventricle into the aorta, becomes severely narrowed, the left ventricle has to pump harder to squeeze the same amount of blood through a smaller hole (see Figure 1). Eventually, the ventricle can become overwhelmed with this increasing load and begin to fail, which leads to congestive heart failure. Other valve disorders in which a valve does not close properly—resulting in a "leaky" valve, where large amounts of blood essentially go backward during portions of the cardiac cycle—also can lead to congestive heart failure.
Finally, damage to heart muscle from causes other than artery or blood flow problems is known as cardiomyopathy and can cause congestive heart failure. Cardiomyopathy can result from infections (myocarditis), alcohol abuse, diabetes, high blood pressure, muscle degeneration, and the toxic effects of certain drugs (such as cancer drugs and cocaine).
What signs of congestive heart failure are present on physical examination?
A damaged and weak heart muscle often can be discovered when the doctor feels for or palpates the area of the chest overlying the heart. When the physician listens to or auscultates the heart, murmurs, extra heart sounds, or arrhythmias may be present, which indicate a particular underlying cause of congestive heart failure. Auscultation of the lungs may reveal "crackles" due to the presence of fluid in the lungs, which is a common finding in acute congestive heart failure. Swelling (edema) may be present in the ankles and feet or, in severe cases, may extend into the thighs and belly region.
Which types of noninvasive tests can be performed to help diagnose the cause of congestive heart failure?
A chest x-ray can provide information about the heart's shape and size. Abnormalities can suggest underlying weak heart function or the presence of significant valvular abnormalities. An electrocardiogram (ECG) shows the pattern of the heartbeat and also reveals data about the size of the heart chambers and whether a prior heart attack occurred. An ultrasound of the heart (called an echocardiogram) can provide detailed information about the size, structure, and movement of the heart muscle and valves. Two types of stress tests can be performed to determine the heart's response to exercise and can help detect narrowed and/or clogged heart vessels: exercise-based and pharmacologic. Pharmacologic tests are employed in people who cannot exercise easily on a treadmill; these tests utilize medications like adenosine and dobutamine that stress the heart. Nuclear scans are often done in conjunction with stress tests; these pictures can help localize areas of the heart that have abnormal blood flow.
What information can cardiac catheterization provide about the cause and prognosis of congestive heart failure?
Cardiac catheterization, Cardiac catheterization, is often performed to determine the problem(s) that led to the development of congestive heart failure. The procedure is done under local anesthesia. A large intravenous line is placed in the groin or arm area. Catheters are then guided up into the heart using x-ray guidance. Pressures can be measured within the heart's main pumping chamber, and the squeezing power of the heart can be evaluated. A special kind of x-ray, called an angiogram, is then taken of the heart's arteries by injecting x-ray contrast fluid directly into the main vessels that supply the heart. The angiogram pictures reveal any clogged arteries or narrowings that can often be the primary cause of congestive heart failure.
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