This study focuses on individuals living with Pulmonary Hypertension, a condition where the blood pressure in the arteries of the lungs is too high, specifically in those who also have Heart Failure with Preserved Ejection Fraction. This type of heart failure occurs when the heart muscle becomes stiff and cannot relax properly to fill with blood between beats, even though the heart’s ability to pump blood out remains relatively normal. The purpose of the study is to evaluate the effectiveness and safety of a medication called levosimendan compared to a placebo.

Participants in the study will be assigned to receive either the active medication, levosimendan, or a placebo, which is an inactive substance, through an oral hard gelatin capsule. This assignment is done through a randomized process, meaning it is determined by chance, and a double-blind method, where neither the participants nor the researchers know which substance is being administered. The treatment period lasts for 26 weeks, during which the effects on physical activity and general health are monitored.