RESUMO
Although chronic sympathetic activation provides inotropic and chronotropic support to the failing heart, such activation may also have deleterious effects, including the direct cardiotoxic effects of catecholamines, activation of the renin-angiotensin-adosterone system and an increase in myocordial oxygen demand. These observations indicate that beta-blockade might be beneficial in the treatment of heart failure. This suggestion is receiving growing support from clinical trials, which show that beta-blockade improves the clinical and functional status of patients with heart failure resulting from dilated cardiomyopathy or ischaemic heart disease. These trials have also indicated beta blocking agents are much safer in patients with heart failure than was previously thought, provided that they are introduced at a low dose and titrated carefully. Newer beta blocking agents have ancillary properties that may be important in the treatment of heart failure. Bucindolol and carvedilol have vasodilating effects that may upload the failing heart, and carvedilol also has antiproliferative and antioxidant properties not shared by other beta blocking agents. Carvedilol is the only beta blocking agent that has reduced overall mortality in patients with heart failure in controlled clinical trials, and it also reduces hospitalization and improves the global assessment of patients. A large comparative trial against other beta blocking agents to confirm that these benefits are unique to carvedilol is about to be launched. Further clinical experience is required to determine the optimum use of carvedilol in the treatment of heart failure. The results obtained so far with carvedilol suggest that the management of heart failure is about to undergo a significant change(AU)
