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 College of Cardiology held in March 2010. Unpublished reports should be considered as preliminary, since analyses may change in the final publication. Results from DOSE suggest that giving diuretics using a high-dose, bolus strategy may be better than using lower doses or a continuous infusion for patients with acute decompensated heart failure. In the ASPIRE study, addition of aliskiren to standard therapy failed to attenuate left ventricular remodelling in post-MI patients and was associated with more adverse events. In CONNECT, remote monitoring reduced the time from CRT-D- or ICD-detected events to clinical decision and this was associated with fewer clinic visits and shorter hospitalizations. An analysis from STICH testing the effects of surgical ventricular reconstruction showed no benefit in the sub-group of patients who achieved a greater reduction in LV volume. STOP-AF and CABANA did not provide convincing evidence of the effectiveness or safety of catheter ablation for the treatment of AF. RACE II suggests that lenient heart rate control might be as effective as strict rate control in patients with permanent atrial fibrillation. In EVEREST II, a catheter-based mitral valve repair procedure using the MitraClip system had similar efficacy to traditional surgery but with fewer short-term adverse effects. Valsartan reduced progression to diabetes in patients with impaired glucose tolerance but had no effect on cardiovascular events in NAVIGATOR. In ACCORD, strict blood pressure control failed to reduce the risk of overall cardiovascular events in high-risk diabetic patients.