Summary

The phosphodiesterase type 5 (PDE-5) inhibitor sildenafil failed to improve peak exercise capacity in patients with diastolic heart failure (HF) in a double-blind, placebo-controlled, randomized clinical trial. Results from the Evaluating the Effectiveness of Sildenafil at Improving Health Outcomes and Exercise Ability in People With Diastolic Heart Failure trial [RELAX; Redfield MM et al. JAMA 2013] did not replicate the cardiovascular benefits of PDE-5 inhibition obtained in studies of experimental HF and small clinical studies.