Clinical Pharmacology of Drugs Used in Heart Failure

CLINICAL PHARMACOLOGY OF DRUGS USED IN HEART FAILURE

The American College of Cardiology/American Heart Association (ACC/AHA) guidelines for management of chronic heart failure specify four stages in the development of heart failure (Table 13–3). Patients in stage A are at high risk because of other disease but have no signs or symptoms of heart failure. Stage B patients have evidence of structural heart disease but no symptoms of heart failure. Stage C patients have structural heart disease and symp-toms of failure, and symptoms are responsive to ordinary therapy. Stage D patients have heart failure refractory to ordinary therapy, and special interventions (resynchronization therapy, transplant) are required.

Once stage C is reached, the severity of heart failure is usually described according to a scale devised by the New York Heart Association. Class I failure is associated with no limitations on ordinary activities, and symptoms that occur only with greater than ordinary exercise. Class II is characterized by slight limitation of activities, and results in fatigue and palpitations with ordinary physical activity. Class III failure results in no symptoms at rest, but fatigue, shortness of breath, and tachycardia occur with less than ordinary physical activity. Class IV is associated with symp-toms even when the patient is at rest.