In a video originally posted on TheHeart.org | Medscape Cardiology, Naveen L. Pereira, M.D., interviews Barry A. Borlaug, M.D., and Margaret M. Redfield, M.D., on the background, results and implications of the unequivocal results in the Improve Clinical Status and Exercise Capacity in Diastolic Heart Failure (RELAX) trial. The results seem to question the role of PDE-5 inhibition in the treatment of HF-PEF and will inform future research in the area.