Several lines of evidence have suggested that Advanced Glycation End-products (AGEs) play a role in the development and progression of heart failure. The AGE-crosslink breaker Alagebrium improved cardiac function and symptoms in experimental preclinical and small human heart failure studies. These results have not yet been confirmed in a randomized controlled clinical trial. Objective: to evaluate the safety and efficacy of alagebrium in subjects diagnosed with heart failure. This is a randomized, double-blind, placebo-controlled trial to assess the effects of 400 mg (2 x 100 mg bid) of alagebrium versus placebo over 9 months. 100 subjects will be studied (50 per treatment group) in approximately 6 centers. Procedures: exercise testing (VO2 max; the primary variable), ECGs and blood sampling.