Controlled and uncontrolled studies suggested that beta-blockade improves ventricular function in congestive heart failure. Several trials suggested that beta-blockers may also reduce mortality. In the Beta-Blocker Heart Attack Trial, patients with a history of heart failure had less cardiac and sudden-death mortality than those who did not. Patients with a low ejection fraction in the Cardiac Arrhythmia Suppression Trial who were treated with beta-blockade also had a reduction in mortality. The Metoprolol in Dilated Cardiomyopathy trial randomized patients with dilated cardiomyopathies to treatment with metoprolol or placebo. There was a trend toward reduction in a morbidity and mortality endpoint in patients treated with metoprolol, but this was due entirely to a reduction in the need for cardiac transplantation. Thus, despite a reasonable theoretical basis and suggestive clinical studies, the concept that beta-blockers reduced mortality in congestive heart failure patients was unproved.