HEART FAILURE
What Is Heart Failure? Heart failure occurs when the heart is unable to pump sufficient blood to meet the body's demand. It is not a single disease entity, but rather the end result of a variety of cardiovascular problems. When heart tissue is damaged and the function of the heart is compromised, the body initiates compensatory responses such as increased heart rate and thickening of the heart's muscular wall. Although these changes initially help to maintain blood flow, ultimately they put the heart under extra strain. It is the combination of the initial heart damage plus the compensatory responses that results in heart failure.
What Causes Heart Failure? The five most common causes of heart failure are coronary artery disease (due to atherosclerosis), valvular heart disease, high blood pressure, alcohol, and a disease of heart muscle known as dilated cardiomyopathy. Coronary artery disease accounts for 60 to 70% of all cases of heart failure. Each of these five conditions can cause heart failure by damaging heart muscle and therefore increasing the workload on the remainder of the heart. Consequently, the muscle thickens with increased work, like any other muscle, and the heart beats faster. This is problematic as the heart is likely to outgrow its own blood supply. As the functional capacity of the heart declines, blood pressure drops, and special pressure sensors cause the blood vessels to constrict and cause the kidneys to retain salt and water. These alterations are intended to maintain blood flow to all parts of the body, but also increase the workload of the heart, leading to further damage; thus a vicious cycle begins.
What Are The Signs And Symptoms Of Heart Failure? The signs and symptoms of heart failure are due to a backlog of pressure in the blood vessels as the heart is unable to maintain adequate forward flow. Consequently, heart failure is often termed congestive heart failure. Shortness of breath and dry cough occur due to accumulation of fluid in the lungs. If heart failure develops over time, the person will first experience trouble breathing upon exertion; as the disease progresses, the person may become short of breath at rest or during the night. (Awakening from sleep due to difficulty in breathing is known as "paroxysmal nocturnal dyspnea.") The backup of fluid elsewhere in the circulation results in swelling of the feet and ankles (edema) and an increase in abdominal girth due to fluid in the abdominal cavity (ascites). The person may notice an increased heart rate and palpitations (awareness of the heart beat). Other symptoms of heart failure are dependent upon the original cause of damage to the heart.
With What Might Heart Failure Be Confused? There is no specific diagnostic test for heart failure; investigations will be conducted based on the patient's cardiac history. Most patients with heart failure have a history of heart problems, leaving little doubt as to the cause of their symptoms. That said, respiratory symptoms may be mistaken for lung disease such as adult respiratory distress syndrome or pneumonia. Swelling of the feet, ankles, and abdomen occurs in nephrotic syndrome (a kidney disease characterized by protein loss in the urine), cirrhosis of the liver (found most commonly but not exclusively in alcoholics), and severe venous disease in which fluid leaks from the veins into the surrounding tissues.
What Is The Treatment For Heart Failure? Ideally, heart failure is treated by correcting the underlying cause; however this is not often possible. Therefore the goals of therapy are to relieve symptoms and to minimize the burden on the heart. The person may receive oxygen by nasal prongs or mask to ease the effort of breathing. Bed rest is usually prescribed. The use of drugs called ACE inhibitors is considered standard care in heart failure: these act to dilate the blood vessels and thereby lower the resistance against which the heart pumps. ACE inhibitors also decrease salt and water retention by the kidneys and thus reduce swelling due to fluid retention. To the same end, the person will be encouraged to minimize dietary salt intake and may be given diuretics to further relieve fluid retention. Many other drugs may be prescribed, depending for the most part on the patient's original heart condition. In severe cases of heart failure resistant to medical therapy, a heart transplant is indicated; however, many of the conditions that predispose a person to developing heart disease in the first place (obesity, diabetes) are also contra-indications for transplant surgery!
The Bottom Line: Heart failure is a very serious condition, with a high recurrence rate and a low survival rate. According to one recent study, more than 75% of newly diagnosed people will be readmitted to hospital twice or more within one year; 17% will be readmitted within one month.
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