As first reported by our group in 1975, severe heart failure due to idiopathic dilated cardiomyopathy could be improved in patients receiving beta-blocker therapy starting at a very low dose and followed by a stepwise increase. Since then, these results have been confirmed by our own group and by others, and similar results were also obtained in patients with other forms of cardiomyopathy, including ischaemic cardiomyopathy. In 13 separate studies involving a total of 651 patients with idiopathic dilated cardiomyopathy, beta-blockade for 2 to 19 months (in addition to conventional treatment of heart failure, including angiotensin converting enzyme inhibitor therapy), significantly improved cardiac function. These studies were performed using metoprolol, bucindolol, labetalol and practolol. Eight studies investigated the effects of long term beta-blocker treatment in patients with heart failure and cardiomyopathy due to coronary artery disease, valvular heart disease, diabetes and doxorubicin therapy. A total of 128 patients were treated with metoprolol, carvedilol or bucindolol for periods of 2 to 12 months. All studies reported a significant improvement in cardiac function. Three studies reported results on survival and the need for cardiac transplantation. The first study published by our group reported improved survival in patients with idiopathic dilated cardiomyopathy treated with metoprolol plus digitalis and diuretics compared with a matched control group. In the more recent Metoprolol in Dilated Cardiomyopathy trial, metoprolol treatment in patients with idiopathic dilated cardiomyopathy resulted in an estimated 34% reduction in the number of primary end-points, total number of deaths, and the need for cardiac transplantation compared with placebo treatment. Recently, it was reported that bisoprolol in patients with heart failure due to various forms of cardiomyopathy caused a nonsignificant 21% reduction in mortality compared with placebo. However, larger studies are needed to further study the effects of beta-blockers on the prognosis for patients with Various forms of cardiomyopathy.
