This article provides information and a commentary on landmark trials presented at the European Society of Cardiology Congress in August 2004, relevant to the pathophysiology, prevention or treatment of heart failure. The SENIORS trial suggests that nebivolol is well tolerated and effective in older patients with heart failure, even if left ventricular systolic function is not markedly depressed. However, patients aged >75 years appeared to gain less benefit. Further data on the effects of nebivolol on symptoms and quality of life are awaited. Two new trials of long-term antibiotic prophylaxis after myocardial infarction (ACES and PROVE-IT) showed no benefit. The ACTION trial showed no reduction in serious cardiovascular events with nifedipine GITS in patients with chronic stable angina, despite a substantial reduction in blood pressure. The HF-ACTION trial announced that the first 700 patients of a projected 3000 had been randomised to either an exercise program or encouragement to exercise but without a formal program. The primary outcome measure is death or hospitalisation for any reason.