Medical management of congestive heart failure

Congestive heart failure (CHF) results from cardiac dysfunction due to multiple causes; it is characterized by low cardiac output (insufficient pumping of blood) and congestion of blood and fluid throughout the body. Pulmonary symptoms are particularly important. Between two and three million people in the US are affected by CHF. A discussion is provided of recent developments in the treatment of one type of chronic CHF, which is caused by left ventricular myocardial dysfunction (impairment of function of the left ventricle, the chamber of the heart that pumps blood to the body). Abnormalities in both the pumping phase (systole) and the filling phase (diastole) are described; CHF can result from failure during either phase, but the two kinds of dysfunction require different treatment approaches. Many compensatory mechanisms of the circulatory system are ultimately detrimental to cardiac function. For instance, the levels of catecholamines (substances that cause blood vessel constriction) increase to compensate for heart failure, an adaptation that facilitates return of blood to the heart. Over prolonged periods, high concentrations of catecholamines can damage the heart muscle. CHF patients have a generally poor prognosis; one-year survival rates range between 34 and 70 percent. Therapy should begin with a diagnosis of the left ventricular dysfunction and should attempt to identify the effect of compensatory mechanisms. Some causes of CHF can be treated: these include noncompliance with medications or dietary recommendations, uncontrolled high blood pressure, and uncontrolled cardiac arrhythmias (irregularities in the heartbeat). Therapy with diuretics (drugs that increase salt and water excretion), digitalis (a drug to normalize cardiac rhythm), and vasodilating agents such as angiotensin-converting enzyme inhibitors, which dilate the blood vessels, are described and evaluated. Treatment for CHF is most effective if the disease is diagnosed early and the underlying causes are addressed. (Consumer Summary produced by Reliance Medical Information, Inc.)