Beta-blockers in heart failure--the evidence from clinical trials.

There are good theoretical reasons for supposing that long-term treatment with a beta-blocker would improve symptoms and survival in patients with heart failure. A series of small studies have shown that beta-blockers improve haemodynamic parameters, but it is well known that these correlate poorly with symptoms. There is some evidence that exercise tolerance is also improved. Although there is so far no convincing evidence that beta-blockers prolong survival in patients with heart failure the development of a new generation of these drugs with additional vasodilating properties makes further large studies essential.