Heart failure is a chronic condition in which the heart is unable to pump a sufficient quantity of blood to meet the needs of peripheral tissues.1,2 Essentially, the heart’s pumping ability has been compromised by some form of myocardial disease or dysfunction. The congestive aspect of heart failure arises from the tendency for fluid to accumulate (backs up) in the lungs and peripheral tissues because the heart is unable to maintain forward movement of blood flow.
The primary symptoms associated with congestive heart failure are peripheral edema and a decreased tolerance for physical activity.3,4 Dyspnea and shortness of breath are also common, especially if the left heart is failing and pulmonary congestion is present. In severe cases, cyanosis develops because the heart cannot deliver oxygen to peripheral tissues.
In the United States, approximately 5 million people have been diagnosed with this disease,3 and the incidence of heart failure (number of new cases each year) approaches 700,000.2 The prevalence of heart failure also increases in older adults, and the number of people with heart failure will undoubtedly increase as a larger percentage of our population reaches advanced age.6 This disease is also associated with serious consequences, and the prognosis for congestive heart failure is often poor.2,4 Despite recent advances in medical treatment, approximately 50 percent of patients die within 5 years after they are diagnosed with heart failure.3
Consequently, effective treatment of congestive heart failure is a critical and challenging task. Pharmacotherapy represents one of the primary methods of treating congestive heart failure, and the drugs discussed in this chapter play a vital role in the optimal management of this disease. As with other cardiac problems, the prevalence of congestive heart failure necessitates that members of the health-care team be aware of the pharmacological management of this disease. You will often treat patients with heart failure, and you should be aware of the drugs used to manage this problem. These drugs can, for example, increase contractility and myocardial pumping ability, thus allowing the patient to participate more actively in exercise and the ability to perform activities of daily living.
Drug therapy can likewise have a positive influence on exercise therapy, and vice versa. If drug therapy helps improve myocardial function, that patient will be able to exercise more effectively, which can further strengthen cardiac function, and so forth. Certain heart failure drugs, however, can cause potentially severe side effects that adversely affect the patient’s well-being, and you must be alert for these, especially during exercise sessions. This chapter begins with a brief overview of the pathophysiological changes and characteristics of heart failure. The remainder of the chapter then explores the primary drug strategies used to improve cardiac pumping ability or decrease cardiac workload in patients with heart failure.
PATHOPHYSIOLOGY OF CONGESTIVE HEART FAILURE