This article provides information and a commentary on trials relevant to the pathophysiology, prevention, and treatment of heart failure presented at the annual meeting of the American Heart Association held in Orlando, Florida in 2009. Unpublished reports should be considered as preliminary, as analyses may change in the final publication. Patients with heart failure randomized to high-dose losartan treatment (150 mg) in the HEAAL study had a reduced risk of death or heart failure hospitalization compared with patients in the low-dose (50 mg) group. In FAIR-HF, patients with heart failure and concomitant iron deficiency but without severe anaemia who received iron supplementation therapy demonstrated an improvement in symptoms at 24 weeks compared with placebo. The J-CHF study was too small and was stopped too early to provide definitive evidence about the optimal dose of carvedilol for Japanese patients with heart failure. Results from the HeartMate II study suggest that continuous-flow left ventricular assist devices may offer benefits over pulsatile-flow devices for long-term support in patients with advanced heart failure. In the PACE study, atrial synchronized right ventricular pacing induced adverse effects on left ventricular function compared with atrial synchronized biventricular pacing in patients with standard pacing indications and a normal ejection fraction.